keytool
You use the keytool
command and options to manage a keystore (database) of cryptographic keys, X.509 certificate chains, and trusted certificates.
Synopsis
keytool [commands]
-
commands
-
Commands for
keytool
include the following:-
-certreq
: Generates a certificate request -
-changealias
: Changes an entry's alias -
-delete
: Deletes an entry -
-exportcert
: Exports certificate -
-genkeypair
: Generates a key pair -
-genseckey
: Generates a secret key -
-gencert
: Generates a certificate from a certificate request -
-importcert
: Imports a certificate or a certificate chain -
-importpass
: Imports a password -
-importkeystore
: Imports one or all entries from another keystore -
-keypasswd
: Changes the key password of an entry -
-list
: Lists entries in a keystore -
-printcert
: Prints the content of a certificate -
-printcertreq
: Prints the content of a certificate request -
-printcrl
: Prints the content of a Certificate Revocation List (CRL) file -
-storepasswd
: Changes the store password of a keystore
See Commands and Options for a description of these commands with their options.
-
Description
The keytool
command is a key and certificate management utility. It enables users to administer their own public/private key pairs and associated certificates for use in self-authentication (where a user authenticates themselves to other users and services) or data integrity and authentication services, by using digital signatures. The keytool
command also enables users to cache the public keys (in the form of certificates) of their communicating peers.
A certificate is a digitally signed statement from one entity (person, company, and so on), which says that the public key (and some other information) of some other entity has a particular value. When data is digitally signed, the signature can be verified to check the data integrity and authenticity. Integrity means that the data hasn’t been modified or tampered with, and authenticity means that the data comes from the individual who claims to have created and signed it.
The keytool
command also enables users to administer secret keys and passphrases used in symmetric encryption and decryption (Data Encryption Standard).
The keytool
command stores the keys and certificates in a keystore.
Command and Option Notes
The following notes apply to the descriptions in Commands and Options:
-
All command and option names are preceded by a hyphen sign (
-
). -
Options for each command can be provided in any order.
-
All items not italicized or in braces ({ }) or brackets ([ ]) are required to appear as is.
-
Braces surrounding an option signify that a default value is used when the option isn’t specified on the command line. Braces are also used around the
-v
,-rfc
, and-J
options, which have meaning only when they appear on the command line. They don’t have any default values. -
Brackets surrounding an option signify that the user is prompted for the values when the option isn’t specified on the command line. For the
-keypass
option, if you don’t specify the option on the command line, then thekeytool
command first attempts to use the keystore password to recover the private/secret key. If this attempt fails, then thekeytool
command prompts you for the private/secret key password. -
Items in italics (option values) represent the actual values that must be supplied. For example, here is the format of the
-printcert
command:keytool -printcert {-file cert_file} {-v}
When you specify a
-printcert
command, replacecert_file
with the actual file name, such as:keytool -printcert -file VScert.cer
-
Option values must be enclosed in quotation marks when they contain a blank (space).
-
The
-help
command is the default. Runningkeytool
without options is the same as runningkeytool -help
. -
If multiple commands are specified, only the last one is recognized. The only exception is that if
-help
is provided along with another command, thekeytool
command will print detailed help for that command. -
There are two kinds of options. One kind of option is single-valued and should be only provided once. If a single-valued option is provided multiple times, the value of the last one is used. The other type of option is multiple-valued and can be provided multiple times and all values are used. The only multiple-valued option supported now is the
-ext
option used to generate X.509v3 certificate extensions.
Commands and Options
The keytool commands and their options can be grouped by the tasks that they perform.
Commands for Creating or Adding Data to the Keystore:
-
-gencert
-
-genkeypair
-
-genseckey
-
-importcert
-
-importpass
Commands for Importing Contents from Another Keystore:
-
-importkeystore
Commands for Generating a Certificate Request:
-
-certreq
-
-exportcert
Commands for Displaying Data :
-
-list
-
-printcert
-
-printcertreq
-
-printcrl
Commands for Managing the Keystore:
-
-storepasswd
-
-keypasswd
-
-delete
-
-changealias
Commands for Creating or Adding Data to the Keystore
-
-gencert
-
The following are the available options for the
-gencert
command:-
{
-rfc
}: Output in RFC (Request For Comment) style -
{
-infile infile
}: Input file name -
{
-outfile outfile
}: Output file name -
{
-alias alias
}: Alias name of the entry to process -
{
-sigalg sigalg
}: Signature algorithm name -
{
-dname dname
}: Distinguished name -
{
-startdate startdate
}: Certificate validity start date and time -
{
-ext ext
}*: X.509 extension -
{
-validity days
}: Validity number of days -
[
-keypass arg
]: Key password -
{
-keystore keystore
}: Keystore name -
[
-storepass arg
]: Keystore password -
{
-storetype type
}: Keystore type -
{
-providername name
}: Provider name -
{
-addprovider name
[-providerarg arg
]}: Adds a security provider by name (such as SunPKCS11) with an optional configure argument. The value of the security provider is the name of a security provider that is defined in a module.For example,
keytool -addprovider SunPKCS11 -providerarg some.cfg ...
Note:
For compatibility reasons, the SunPKCS11 and OracleUcrypto providers can still be loaded with
-providerclass sun.security.pkcs11.SunPKCS11
and-providerclass com.oracle.security.crypto.UcryptoProvider
even if they are now defined in modules. These are the only modules included in JDK that need a configuration, and therefore the most widely used with the-providerclass
option. For legacy security providers located on classpath and loaded by reflection,-providerclass
should still be used. - {
-providerclass class
[-providerarg arg
]}: Add security provider by fully qualified class name with an optional configure argument. For example, ifMyProvider
is a legacy provider loaded via reflection,keytool -providerclass com.example.MyProvider ...
-
{
-providerpath list
}: Provider classpath -
{
-v
}: Verbose output -
{
-protected
}: Password provided through a protected mechanism
Use the
-gencert
command to generate a certificate as a response to a certificate request file (which can be created by thekeytool -certreq
command). The command reads the request either frominfile
or, if omitted, from the standard input, then signs it by using the alias's private key, and outputs the X.509 certificate into eitheroutfile
or, if omitted, to the standard output. When-rfc
is specified, the output format is Base64-encoded PEM; otherwise, a binary DER is created.The
-sigalg
value specifies the algorithm that should be used to sign the certificate. Thestartdate
argument is the start time and date that the certificate is valid. Thedays
argument tells the number of days for which the certificate should be considered valid.When
dname
is provided, it is used as the subject of the generated certificate. Otherwise, the one from the certificate request is used.The
-ext
value shows what X.509 extensions will be embedded in the certificate. Read Common Command Options for the grammar of-ext
.The
-gencert
option enables you to create certificate chains. The following example creates a certificate,e1
, that contains three certificates in its certificate chain.The following commands create four key pairs named
ca
,ca1
,ca2
, ande1
:keytool -alias ca -dname CN=CA -genkeypair keytool -alias ca1 -dname CN=CA -genkeypair keytool -alias ca2 -dname CN=CA -genkeypair keytool -alias e1 -dname CN=E1 -genkeypair
The following two commands create a chain of signed certificates;
ca
signsca1
andca1
signsca2
, all of which are self-issued:keytool -alias ca1 -certreq | keytool -alias ca -gencert -ext san=dns:ca1 | keytool -alias ca1 -importcert keytool -alias ca2 -certreq | keytool -alias ca1 -gencert -ext san=dns:ca2 | keytool -alias ca2 -importcert
The following command creates the certificate
e1
and stores it in thee1.cert
file, which is signed byca2
. As a result,e1
should containca
,ca1
, andca2
in its certificate chain:keytool -alias e1 -certreq | keytool -alias ca2 -gencert > e1.cert
-
-
-genkeypair
-
The following are the available options for the
-genkeypair
command:-
{
-alias alias
}: Alias name of the entry to process -
{
-keyalg alg
}: Key algorithm name -
{
-keysize size
}: Key bit size - {
-groupname name
}: Group name. For example, an Elliptic Curve name. -
{
-sigalg alg
}: Signature algorithm name -
[
-dname name
]: Distinguished name -
{
-startdate date
}: Certificate validity start date and time -
[
-ext value
]*: X.509 extension -
{
-validity days
}: Validity number of days -
[
-keypass arg
]: Key password -
{
-keystore keystore
}: Keystore name -
[
-storepass arg
]: Keystore password -
{
-storetype type
}: Keystore type -
{
-providername name
}: Provider name -
{
-addprovider name
[-providerarg arg
]}: Add security provider by name (such as SunPKCS11) with an optional configure argument. -
{
-providerclass class
[-providerarg arg
]}: Add security provider by fully qualified class name with an optional configure argument. -
{
-providerpath list
}: Provider classpath -
{
-v
}: Verbose output -
{
-protected
}: Password provided through a protected mechanism
Use the
-genkeypair
command to generate a key pair (a public key and associated private key). Wraps the public key in an X.509 v3 self-signed certificate, which is stored as a single-element certificate chain. This certificate chain and the private key are stored in a new keystore entry that is identified by its alias.The
-keyalg
value specifies the algorithm to be used to generate the key pair, and the-keysize
value specifies the size of each key to be generated. The-sigalg
value specifies the algorithm that should be used to sign the self-signed certificate. This algorithm must be compatible with the-keyalg
value.The
-groupname
value specifies the named group (for example, the standard or predefined name of an Elliptic Curve) of the key to be generated. Only one of-groupname
and-keysize
can be specified.The
-dname
value specifies the X.500 Distinguished Name to be associated with the value of-alias
, and is used as the issuer and subject fields in the self-signed certificate. If a distinguished name is not provided at the command line, then the user is prompted for one.The value of
-keypass
is a password used to protect the private key of the generated key pair. If a password is not provided, then the user is prompted for it. If you press the Return key at the prompt, then the key password is set to the same password as the keystore password. The-keypass
value must have at least six characters.The value of
-startdate
specifies the issue time of the certificate, also known as the "Not Before" value of the X.509 certificate's Validity field.The option value can be set in one of these two forms:
-
([+-]nnn[ymdHMS])+
-
[yyyy/mm/dd] [HH:MM:SS]
With the first form, the issue time is shifted by the specified value from the current time. The value is a concatenation of a sequence of subvalues. Inside each subvalue, the plus sign (+) means shift forward, and the minus sign (-) means shift backward. The time to be shifted is
nnn
units of years, months, days, hours, minutes, or seconds (denoted by a single character ofy
,m
,d
,H
,M
, orS
respectively). The exact value of the issue time is calculated by using thejava.util.GregorianCalendar.add(int field, int amount)
method on each subvalue, from left to right. For example, the issue time can be specified by:Calendar c = new GregorianCalendar(); c.add(Calendar.YEAR, -1); c.add(Calendar.MONTH, 1); c.add(Calendar.DATE, -1); return c.getTime()
With the second form, the user sets the exact issue time in two parts, year/month/day and hour:minute:second (using the local time zone). The user can provide only one part, which means the other part is the same as the current date (or time). The user must provide the exact number of digits shown in the format definition (padding with 0 when shorter). When both date and time are provided, there is one (and only one) space character between the two parts. The hour should always be provided in 24–hour format.
When the option isn’t provided, the start date is the current time. The option can only be provided one time.
The value of
date
specifies the number of days (starting at the date specified by-startdate
, or the current date when-startdate
isn’t specified) for which the certificate should be considered valid. -
-
-genseckey
-
The following are the available options for the
-genseckey
command:-
{
-alias alias
}: Alias name of the entry to process -
[
-keypass arg
] : Key password -
{
-keyalg alg
}: Key algorithm name -
{
-keysize size
}: Key bit size -
{
-keystore keystore
}: Keystore name -
[
-storepass arg
]: Keystore password -
{
-storetype type
}: Keystore type -
{
-providername name
}: Provider name -
{
-addprovider name
[-providerarg arg
]}: Add security provider by name (such as SunPKCS11) with an optional configure argument. -
{
-providerclass class
[-providerarg arg
]}: Add security provider by fully qualified class name with an optional configure argument. -
{
-providerpath list
}: Provider classpath -
{
-v
}: Verbose output -
{
-protected
}: Password provided through a protected mechanism
Use the
-genseckey
command to generate a secret key and store it in a newKeyStore.SecretKeyEntry
identified byalias
.The value of
-keyalg
specifies the algorithm to be used to generate the secret key, and the value of-keysize
specifies the size of the key that is generated. The-keypass
value is a password that protects the secret key. If a password is not provided, then the user is prompted for it. If you press the Return key at the prompt, then the key password is set to the same password that is used for the-keystore
. The-keypass
value must contain at least six characters. -
-
-importcert
-
The following are the available options for the
-importcert
command:-
{
-noprompt
}: Do not prompt -
{
-trustcacerts
}: Trust certificates from cacerts -
{
-protected
}: Password is provided through protected mechanism -
{
-alias alias
}: Alias name of the entry to process -
{
-file file
}: Input file name -
[
-keypass arg
]: Key password -
{
-keystore keystore
}: Keystore name -
{
-cacerts
}: Access the cacerts keystore -
[
-storepass arg
]: Keystore password -
{
-storetype type
}: Keystore type -
{
-providername name
}: Provider name -
{
-addprovider name
[-providerarg arg
]}: Add security provider by name (such as SunPKCS11) with an optional configure argument. -
{
-providerclass class
[-providerarg arg
]}: Add security provider by fully qualified class name with an optional configure argument. -
{
-providerpath list
}: Provider classpath -
{
-v
}: Verbose output
Use the
-importcert
command to read the certificate or certificate chain (where the latter is supplied in a PKCS#7 formatted reply or in a sequence of X.509 certificates) from-file file
, and store it in thekeystore
entry identified by-alias
. If-file file
is not specified, then the certificate or certificate chain is read fromstdin
.The
keytool
command can import X.509 v1, v2, and v3 certificates, and PKCS#7 formatted certificate chains consisting of certificates of that type. The data to be imported must be provided either in binary encoding format or in printable encoding format (also known as Base64 encoding) as defined by the Internet RFC 1421 standard. In the latter case, the encoding must be bounded at the beginning by a string that starts with-----BEGIN
, and bounded at the end by a string that starts with-----END
.You import a certificate for two reasons: To add it to the list of trusted certificates, and to import a certificate reply received from a certificate authority (CA) as the result of submitting a Certificate Signing Request (CSR) to that CA. See the
-certreq
command in Commands for Generating a Certificate Request.The type of import is indicated by the value of the
-alias
option. If the alias doesn’t point to a key entry, then thekeytool
command assumes you are adding a trusted certificate entry. In this case, the alias shouldn’t already exist in the keystore. If the alias does exist, then thekeytool
command outputs an error because a trusted certificate already exists for that alias, and doesn’t import the certificate. If-alias
points to a key entry, then thekeytool
command assumes that you’re importing a certificate reply. -
-
-importpass
-
The following are the available options for the
-importpass
command:-
{
-alias alias
}: Alias name of the entry to process -
[
-keypass arg
]: Key password -
{
-keyalg alg
}: Key algorithm name -
{
-keysize size
}: Key bit size -
{
-keystore keystore
}: Keystore name -
[
-storepass arg
]: Keystore password -
{
-storetype type
}: Keystore type -
{
-providername name
}: Provider name -
{
-addprovider name
[-providerarg arg
]}: Add security provider by name (such as SunPKCS11) with an optional configure argument. -
{
-providerclass class
[-providerarg arg
]}: Add security provider by fully qualified class name with an optional configure argument. -
{
-providerpath list
}: Provider classpath -
{
-v
}: Verbose output -
{
-protected
}: Password provided through a protected mechanism
Use the
-importpass
command to import a passphrase and store it in a newKeyStore.SecretKeyEntry
identified by-alias
. The passphrase may be supplied via the standard input stream; otherwise the user is prompted for it. The-keypass
option provides a password to protect the imported passphrase. If a password is not provided, then the user is prompted for it. If you press the Return key at the prompt, then the key password is set to the same password as that used for thekeystore
. The-keypass
value must contain at least six characters. -
Commands for Importing Contents from Another Keystore
-
-importkeystore
-
The following are the available options for the
-importkeystore
command:-
{
-srckeystore keystore
}: Source keystore name -
{
-destkeystore keystore
}: Destination keystore name -
{
-srcstoretype type
}: Source keystore type -
{
-deststoretype type
}: Destination keystore type -
[
-srcstorepass arg
]: Source keystore password -
[
-deststorepass arg
]: Destination keystore password -
{
-srcprotected
Source keystore password protected -
{
-destprotected
}: Destination keystore password protected -
{
-srcprovidername name
}: Source keystore provider name -
{
-destprovidername name
}: Destination keystore provider name -
{
-srcalias alias
}: Source alias -
{
-destalias alias
}: Destination alias -
[
-srckeypass arg
]: Source key password -
[
-destkeypass arg
]: Destination key password -
{
-noprompt
}: Do not prompt -
{
-addprovider name
[-providerarg arg
]}: Add security provider by name (such as SunPKCS11) with an optional configure argument. -
{
-providerclass class
[-providerarg arg
]}: Add security provider by fully qualified class name with an optional configure argument -
{
-providerpath list
}: Provider classpath -
{
-v
}: Verbose output
Note:
This is the first line of all options:-srckeystore keystore -destkeystore keystore
Use the
-importkeystore
command to import a single entry or all entries from a source keystore to a destination keystore.Note:
If you do not specify
-destkeystore
when using thekeytool -importkeystore
command, then the default keystore used is$HOME/.keystore
.When the
-srcalias
option is provided, the command imports the single entry identified by the alias to the destination keystore. If a destination alias isn’t provided with-destalias
, then-srcalias
is used as the destination alias. If the source entry is protected by a password, then-srckeypass
is used to recover the entry. If-srckeypass
isn’t provided, then thekeytool
command attempts to use-srcstorepass
to recover the entry. If-srcstorepass
is not provided or is incorrect, then the user is prompted for a password. The destination entry is protected with-destkeypass
. If-destkeypass
isn’t provided, then the destination entry is protected with the source entry password. For example, most third-party tools requirestorepass
andkeypass
in a PKCS #12 keystore to be the same. To create a PKCS#12 keystore for these tools, always specify a-destkeypass
that is the same as-deststorepass
.If the
-srcalias
option isn’t provided, then all entries in the source keystore are imported into the destination keystore. Each destination entry is stored under the alias from the source entry. If the source entry is protected by a password, then-srcstorepass
is used to recover the entry. If-srcstorepass
is not provided or is incorrect, then the user is prompted for a password. If a source keystore entry type isn’t supported in the destination keystore, or if an error occurs while storing an entry into the destination keystore, then the user is prompted either to skip the entry and continue or to quit. The destination entry is protected with the source entry password.If the destination alias already exists in the destination keystore, then the user is prompted either to overwrite the entry or to create a new entry under a different alias name.
If the
-noprompt
option is provided, then the user isn’t prompted for a new destination alias. Existing entries are overwritten with the destination alias name. Entries that can’t be imported are skipped and a warning is displayed. -
Commands for Generating a Certificate Request
-
-certreq
-
The following are the available options for the
-certreq
command:-
{
-alias alias
}: Alias name of the entry to process -
{
-sigalg alg
}: Signature algorithm name -
{
-file file
}: Output file name -
[
-keypass arg
]: Key password -
{
-keystore keystore
}: Keystore name -
{
-dname name
}: Distinguished name -
{
-ext value
}: X.509 extension -
[
-storepass arg
]: Keystore password -
{
-storetype type
}: Keystore type -
{
-providername name
}: Provider name -
{
-addprovider name
[-providerarg arg
]}: Add security provider by name (such as SunPKCS11) with an optional configure argument. -
{
-providerclass class
[-providerarg arg
]}: Add security provider by fully qualified class name with an optional configure argument. -
{
-providerpath list
}: Provider classpath -
{
-v
}: Verbose output -
{
-protected
}: Password provided through a protected mechanism
Use the
-certreq
command to generate a Certificate Signing Request (CSR) using the PKCS #10 format.A CSR is intended to be sent to a CA. The CA authenticates the certificate requestor (usually offline) and returns a certificate or certificate chain to replace the existing certificate chain (initially a self-signed certificate) in the keystore.
The private key associated with
alias
is used to create the PKCS #10 certificate request. To access the private key, the correct password must be provided. If-keypass
isn’t provided at the command line and is different from the password used to protect the integrity of the keystore, then the user is prompted for it. If-dname
is provided, then it is used as the subject in the CSR. Otherwise, the X.500 Distinguished Name associated with alias is used.The
-sigalg
value specifies the algorithm that should be used to sign the CSR.The CSR is stored in the
-file file
. If a file is not specified, then the CSR is output to-stdout
.Use the
-importcert
command to import the response from the CA. -
Commands for Exporting Data
-
-exportcert
-
The following are the available options for the
-exportcert
command:-
{
-rfc
}: Output in RFC style -
{
-alias alias
}: Alias name of the entry to process -
{
-file file
}: Output file name -
{
-keystore keystore
}: Keystore name -
{
-cacerts
}: Access the cacerts keystore -
[
-storepass arg
]: Keystore password -
{
-storetype type
}: Keystore type -
{
-providername name
}: Provider name -
{
-addprovider name
[-providerarg arg
]}: Add security provider by name (such as SunPKCS11) with an optional configure argument. -
{
-providerclass class
[-providerarg arg
]}: Add security provider by fully qualified class name with an optional configure argument. -
{
-providerpath list
}: Provider classpath -
{
-v
}: Verbose output -
{
-protected
}: Password provided through a protected mechanism
Use the
-exportcert
command to read a certificate from the keystore that is associated with-alias alias
and store it in thecert_file
file. When a file is not specified, the certificate is output tostdout
.By default, the certificate is output in binary encoding. If the
-rfc
option is specified, then the output in the printable encoding format defined by the Internet RFC 1421 Certificate Encoding Standard.If
-alias
refers to a trusted certificate, then that certificate is output. Otherwise,-alias
refers to a key entry with an associated certificate chain. In that case, the first certificate in the chain is returned. This certificate authenticates the public key of the entity addressed by-alias
. -
Commands for Displaying Data
-
-list
-
The following are the available options for the
-list
command:-
{
-rfc
}: Output in RFC style -
{
-alias alias
}: Alias name of the entry to process -
{
-keystore keystore
}: Keystore name -
{
-cacerts
}: Access the cacerts keystore -
[
-storepass arg
]: Keystore password -
{
-storetype type
}: Keystore type -
{
-providername name
}: Provider name -
{
-addprovider name
[-providerarg arg
]}: Add security provider by name (such as SunPKCS11) with an optional configure argument. -
{
-providerclass class
[-providerarg arg
] }: Add security provider by fully qualified class name with an optional configure argument. -
{
-providerpath list
}: Provider classpath -
{
-v
}: Verbose output -
{
-protected
}: Password provided through a protected mechanism
Use the
-list
command to print the contents of the keystore entry identified by-alias
tostdout
. If-alias alias
is not specified, then the contents of the entire keystore are printed.By default, this command prints the SHA-256 fingerprint of a certificate. If the
-v
option is specified, then the certificate is printed in human-readable format, with additional information such as the owner, issuer, serial number, and any extensions. If the-rfc
option is specified, then the certificate contents are printed by using the printable encoding format, as defined by the Internet RFC 1421 Certificate Encoding Standard.Note:
You can’t specify both
-v
and-rfc
in the same command. Otherwise, an error is reported. -
-
-printcert
-
The following are the available options for the
-printcert
command:-
{
-rfc
}: Output in RFC style -
{
-file cert_file
}: Input file name -
{
-sslserver server[:port]
}: Secure Sockets Layer (SSL) server host and port -
{
-jarfile JAR_file
}: Signed.jar
file -
{
-v
}: Verbose output
Use the
-printcert
command to read and print the certificate from-file cert_file
, the SSL server located-sslserver server[:port]
, or the signed JAR file specified by-jarfile JAR_file
. It prints its contents in a human-readable format. When a port is not specified, the standard HTTPS port 443 is assumed.Note:
The
-sslserver
and-file
options can’t be provided in the same command. Otherwise, an error is reported. If you don’t specify either option, then the certificate is read fromstdin
.When
-rfc
is specified, thekeytool
command prints the certificate in PEM mode as defined by the Internet RFC 1421 Certificate Encoding standard.If the certificate is read from a file or
stdin
, then it might be either binary encoded or in printable encoding format, as defined by the RFC 1421 Certificate Encoding standard.If the SSL server is behind a firewall, then the
-J-Dhttps.proxyHost=proxyhost
and-J-Dhttps.proxyPort=proxyport
options can be specified on the command line for proxy tunneling.Note:
This option can be used independently of a keystore.
-
-
-printcertreq
-
The following are the available options for the
-printcertreq
command:-
{
-file file
}: Input file name -
{
-v
}: Verbose output
Use the
-printcertreq
command to print the contents of a PKCS #10 format certificate request, which can be generated by thekeytool -certreq
command. The command reads the request from file. If there is no file, then the request is read from the standard input. -
-
-printcrl
-
The following are the available options for the
-printcrl
command:-
-file crl
: Input file name -
{
-v
}: Verbose output
Use the
-printcrl
command to read the Certificate Revocation List (CRL) from-file crl
. A CRL is a list of the digital certificates that were revoked by the CA that issued them. The CA generates thecrl
file.Note:
This option can be used independently of a keystore.
-
Commands for Managing the Keystore
-
-storepasswd
-
The following are the available options for the
-storepasswd
command:-
[
-new arg
]: New password -
{
-keystore keystore
}: Keystore name -
{
-cacerts
}: Access the cacerts keystore -
[
-storepass arg
]: Keystore password -
{
-storetype type
}: Keystore type -
{
-providername name
}: Provider name -
{
-addprovider name
[-providerarg arg
]}: Add security provider by name (such as SunPKCS11) with an optional configure argument. -
{
-providerclass class
[-providerarg arg
]}: Add security provider by fully qualified class name with an optional configure argument. -
{
-providerpath list
}: Provider classpath -
{
-v
}: Verbose output
Use the
-storepasswd
command to change the password used to protect the integrity of the keystore contents. The new password is set by-new arg
and must contain at least six characters. -
-
-keypasswd
-
The following are the available options for the
-keypasswd
command:-
{
-alias alias
}: Alias name of the entry to process -
[
-keypass old_keypass
]: Key password -
[
-new new_keypass
]: New password -
{
-keystore keystore
}: Keystore name -
{
-storepass arg
}: Keystore password -
{
-storetype type
}: Keystore type -
{
-providername name
}: Provider name -
{
-addprovider name
[-providerarg arg
]}: Add security provider by name (such as SunPKCS11) with an optional configure argument. -
{
-providerclass class
[-providerarg arg
]}: Add security provider by fully qualified class name with an optional configure argument. -
{
-providerpath list
}: Provider classpath -
{
-v
}: Verbose output
Use the
-keypasswd
command to change the password (under which private/secret keys identified by-alias
are protected) from-keypass old_keypass
to-new new_keypass
. The password value must contain at least six characters.If the
-keypass
option isn’t provided at the command line and the-keypass
password is different from the keystore password (-storepass arg
), then the user is prompted for it.If the
-new
option isn’t provided at the command line, then the user is prompted for it. -
-
-delete
-
The following are the available options for the
-delete
command:-
[
-alias alias
]: Alias name of the entry to process -
{
-keystore keystore
}: Keystore name -
{
-cacerts
}: Access the cacerts keystore -
[
-storepass arg
]: Keystore password -
{
-storetype type
}: Keystore type -
{
-providername name
}: Provider name -
{
-addprovider name
[-providerarg arg
]}: Add security provider by name (such as SunPKCS11) with an optional configure argument. -
{
-providerclass class
[-providerarg arg
]}: Add security provider by fully qualified class name with an optional configure argument. -
{
-providerpath list
}: Provider classpath -
{
-v
}: Verbose output -
{
-protected
}: Password provided through a protected mechanism
Use the
-delete
command to delete the-alias alias
entry from the keystore. When not provided at the command line, the user is prompted for thealias
. -
-
-changealias
-
The following are the available options for the
-changealias
command:-
{
-alias alias
}: Alias name of the entry to process -
[
-destalias alias
]: Destination alias -
[
-keypass arg
]: Key password -
{
-keystore keystore
}: Keystore name -
{
-cacerts
}: Access the cacerts keystore -
[
-storepass arg
]: Keystore password -
{
-storetype type
}: Keystore type -
{
-providername name
}: Provider name -
{
-addprovider name
[-providerarg arg
]}: Add security provider by name (such as SunPKCS11) with an optional configure argument. -
{
-providerclass class
[-providerarg arg
]}: Add security provider by fully qualified class name with an optional configure argument. -
{
-providerpath list
}: Provider classpath -
{
-v
}: Verbose output -
{
-protected
}: Password provided through a protected mechanism
Use the
-changealias
command to move an existing keystore entry from-alias alias
to a new-destalias alias
. If a destination alias is not provided, then the command prompts you for one. If the original entry is protected with an entry password, then the password can be supplied with the-keypass
option. If a key password is not provided, then the-storepass
(if provided) is attempted first. If the attempt fails, then the user is prompted for a password. -
Commands for Displaying Help Information
--help
to display a list of keytool
commands or to display help information about a specific keytool
command.
-
To display a list of
keytool
commands, enter:keytool --help
-
To display help information about a specific
keytool
command, enter:keytool -command --help
Common Command Options
The -v
option can appear for all commands except
--help
. When the -v
option appears, it
signifies verbose mode, which means that more information is provided in the
output.
The -Joption
argument
can appear for any command. When the -Joption
is used, the specified option
string is passed directly to the Java
interpreter. This option doesn’t contain any spaces. It’s useful for adjusting the
execution environment or memory usage. For a list of possible interpreter options,
enter java -h
or java -X
at the command line.
The following options can appear for all commands operating on a keystore:
-
-addprovider name
-
Used to add a security provider by name (such as SunPKCS11) .
-
-cacerts cacerts
-
Operates on the
cacerts
keystore . This option is equivalent to"-keystore path_to_cacerts -storetype type_of_cacerts"
. An error is reported if the-keystore
or-storetype
option is used with the-cacerts
option. -
-conf file
- Specifies a pre-configured options file.
-
-ext {name{:critical} {=value}}
-
Denotes an X.509 certificate extension. The option can be used in
-genkeypair
and-gencert
to embed extensions into the generated certificate, or in-certreq
to show what extensions are requested in the certificate request. The option can appear multiple times. Thename
argument can be a supported extension name (see Supported Named Extensions ) or an arbitrary OID number. Thevalue
argument, when provided, denotes the argument for the extension. Whenvalue
is omitted, the default value of the extension or the extension itself requires no argument. The:critical
modifier, when provided, means the extension'sisCritical
attribute istrue
; otherwise, it isfalse
. You can use:c
in place of:critical
. -
-keystore keystore
-
The keystore location.
If the JKS
storetype
is used and a keystore file doesn’t yet exist, then certainkeytool
commands can result in a new keystore file being created. For example, ifkeytool -genkeypair
is called and the-keystore
option isn’t specified, the default keystore file named.keystore
is created in the user's home directory if it doesn’t already exist. Similarly, if the-keystore ks_file
option is specified butks_file
doesn’t exist, then it is created. For more information on the JKSstoretype
, see the KeyStore Implementation section in KeyStore aliases.Note that the input stream from the
-keystore
option is passed to theKeyStore.load
method. IfNONE
is specified as the URL, then a null stream is passed to theKeyStore.load
method.NONE
should be specified if the keystore isn’t file-based. For example, when the keystore resides on a hardware token device. -
-protected=true|false
-
Specify this value as
true
when a password must be specified by way of a protected authentication path, such as a dedicated PIN reader. Because there are two keystores involved in the-importkeystore
command, the following two options,-srcprotected
and-destprotected
, are provided for the source keystore and the destination keystore respectively. -
-providerarg arg
-
Used with the
-addprovider
or-providerclass
option to represent an optional string input argument for the constructor ofclass
name. -
-providerclass class
-
Used to specify the name of a cryptographic service provider's master class file when the service provider isn’t listed in the security properties file.
-
-providername name
-
Used to identify a cryptographic service provider's name when listed in the security properties file.
-
-providerpath list
-
Used to specify the provider classpath.
-
-storepass [:env | :file ] argument
-
The password that is used to protect the integrity of the keystore.
If the modifier
env
orfile
isn’t specified, then the password has thevalue
argument, which must contain at least six characters. Otherwise, the password is retrieved as follows:-
env
: Retrieve the password from the environment variable namedargument
. -
file
: Retrieve the password from the file named argument.
Note: All other options that require passwords, such as
-keypass
,-srckeypass
,-destkeypass
,-srcstorepass
, and-deststorepass
, accept theenv
andfile
modifiers. Remember to separate the password option and the modifier with a colon (:).The password must be provided to all commands that access the keystore contents. For such commands, when the
-storepass
option isn’t provided at the command line, the user is prompted for it.When retrieving information from the keystore, the password is optional. If a password is not specified, then the integrity of the retrieved information can’t be verified and a warning is displayed.
-
-
-storetype storetype
-
This qualifier specifies the type of keystore to be instantiated.
Pre-configured options file
A pre-configured options file is a Java properties file that can be specified with
the -conf
option. Each property represents the default option(s)
for a keytool command using keytool.command_name
as the property name. A special property named keytool.all
represents the default option(s) applied to all commands. A property value can
include ${prop}
which will be expanded to the system property
associated with it. If an option value includes white spaces inside, it should be
surrounded by quotation marks (" or '). All property names must be in lower case.
When keytool
is launched with a pre-configured options file, the
value for keytool.all
(if it exists) is prepended to the keytool
command line first, with the value for the command name (if it exists) coming next,
and then the existing options on the command line at last. For a single-valued
option, this allows the property for a specific command to override the
keytool.all
value, and the value specified on the command line
to override both. For multiple-valued options, all of them will be used by
keytool
. See Example of Using a Pre-Configured Options
File below.
Examples of Option Values
The following examples show the defaults for various option values:
-alias "mykey"
-keyalg
"DSA" (when using -genkeypair)
"DES" (when using -genseckey)
-keysize
2048 (when using -genkeypair and -keyalg is "RSA")
2048 (when using -genkeypair and -keyalg is "DSA")
256 (when using -genkeypair and -keyalg is "EC")
56 (when using -genseckey and -keyalg is "DES")
168 (when using -genseckey and -keyalg is "DESede")
-validity 90
-keystore <the file named .keystore in the user's home directory>
-destkeystore <the file named .keystore in the user's home directory>
-storetype <the value of the "keystore.type" property in the
security properties file, which is returned by the static
getDefaultType method in java.security.KeyStore>
-file
stdin (if reading)
stdout (if writing)
-protected false
When generating a certificate or a certificate request, the default signature algorithm (-sigalg
option) is derived from the algorithm of the underlying private key to provide an appropriate level of security strength as follows:
keyalg | keysize | default sigalg |
---|---|---|
DSA |
any size |
SHA256withDSA |
RSA |
<= 3072 <= 7680 > 7680 |
SHA256withRSA SHA384withRSA SHA512withRSA |
EC |
<384 <512 = 512 |
SHA256withECDSA SHA384withECDSA SHA512withECDSA |
Note:
To improve out of the box security, default key size and signature algorithm names are periodically updated to stronger values with each release of the JDK. If interoperability with older releases of the JDK is important, make sure that the defaults are supported by those releases. Alternatively, you can use the -keysize
or -sigalg
options to override the default values at your own risk.
Supported Named Extensions
The keytool
command supports these named extensions. The names aren’t case-sensitive.
-
BC
orBasicContraints
-
Values:
The full form is
ca:{true|false}[,pathlen:len]
orlen
, which is short forca:true,pathlen:len
.When
len
is omitted, the resulting value isca:true
. -
KU
orKeyUsage
-
Values:
usage
(,usage
)*usage
can be one of the following:-
digitalSignature
-
nonRepudiation (contentCommitment
) -
keyEncipherment
-
dataEncipherment
-
keyAgreement
-
keyCertSign
-
cRLSign
-
encipherOnly
-
decipherOnly
Provided there is no ambiguity, the
usage
argument can be abbreviated with the first few letters (such asdig
fordigitalSignature
) or in camel-case style (such asdS
fordigitalSignature
orcRLS
forcRLSign
). Theusage
values are case-sensitive. -
-
EKU
orExtendedKeyUsage
-
Values:
usage
(,usage
)*usage
can be one of the following:-
anyExtendedKeyUsage
-
serverAuth
-
clientAuth
-
codeSigning
-
emailProtection
-
timeStamping
-
OCSPSigning
-
Any OID string
Provided there is no ambiguity, the
usage
argument can be abbreviated with the first few letters or in camel-case style. Theusage
values are case-sensitive. -
-
SAN
orSubjectAlternativeName
-
Values:
type
:value
(,type
:value
)*type
can be one of the following:-
EMAIL
-
URI
-
DNS
-
IP
-
OID
value
argument is the string format value for thetype
. -
-
IAN
orIssuerAlternativeName
-
Values:
Same as
SAN
orSubjectAlternativeName
. -
SIA
orSubjectInfoAccess
-
Values:
method
:location-type
:location-value
(,method:location-type
:location-value
)*method
can be one of the following:-
timeStamping
-
caRepository
-
Any OID
location-type
andlocation-value
arguments can be anytype
:value
supported by theSubjectAlternativeName
extension. -
-
AIA
orAuthorityInfoAccess
-
Values:
Same as
SIA
orSubjectInfoAccess
.Themethod
argument can be one of the following:-
ocsp
-
caIssuers
-
Any OID
-
When name
is OID, the value is the hexadecimal dumped Definite Encoding Rules (DER) encoding of the extnValue
for the extension excluding the OCTET STRING type and length bytes. Other than standard hexadecimal numbers (0-9, a-f, A-F), any extra characters are ignored in the HEX string. Therefore, both 01:02:03:04 and 01020304 are accepted as identical values. When there is no value, the extension has an empty value field.
A special name honored
, used only in -gencert
, denotes how the extensions included in the certificate request should be honored. The value for this name is a comma-separated list of all
(all requested extensions are honored), name{:[critical|non-critical]}
(the named extension is honored, but it uses a different isCritical
attribute), and -name
(used with all
, denotes an exception). Requested extensions aren’t honored by default.
If, besides the -ext honored
option, another named or OID -ext
option is provided, this extension is added to those already honored. However, if this name (or OID) also appears in the honored value, then its value and criticality override that in the request. If an extension of the same type is provided multiple times through either a name or an OID, only the last extension is used.
The subjectKeyIdentifier
extension is always created. For non-self-signed certificates, the authorityKeyIdentifier
is created.
Caution:
Users should be aware that some combinations of extensions (and other certificate fields) may not conform to the Internet standard. See Certificate Conformance Warning.
Examples of Tasks in Creating a keystore
The following examples describe the sequence actions in creating a keystore for managing public/private key pairs and certificates from trusted entities.
Generating the Key Pair
Create a keystore and then generate the key pair.
You can enter the command as a single line such as the following:
keytool -genkeypair -dname "cn=myname, ou=mygroup, o=mycompany, c=mycountry"
-alias business -keypass password
-keystore /working/mykeystore
-storepass passwd -validity 180
The command creates the keystore named mykeystore
in the working directory (provided it doesn’t already exist), and assigns it the password specified by -keypass
. It generates a public/private key pair for the entity whose distinguished name is myname
, mygroup
, mycompany
, and a two-letter country code of mycountry
. It uses the default DSA key generation algorithm to create the keys; both are 2048 bits
The command uses the default SHA256withDSA signature algorithm to create a self-signed certificate that includes the public key and the distinguished name information. The certificate is valid for 180 days, and is associated with the private key in a keystore entry referred to by -alias business
. The private key is assigned the password specified by -keypass
.
The command is significantly shorter when the option defaults are accepted. In this case, no options are required, and the defaults are used for unspecified options that have default values. You are prompted for any required values. You could have the following:
keytool -genkeypair
In this case, a keystore entry with the alias mykey
is created, with a newly generated key pair and a certificate that is valid for 90 days. This entry is placed in your home directory in a keystore named .keystore
. .keystore
is created if it doesn’t already exist. You are prompted for the distinguished name information, the keystore password, and the private key password.
Note:
The rest of the examples assume that you executed the -genkeypair
command without specifying options, and that you responded to the prompts with values equal to those specified in the first -genkeypair
command. For example, a distinguished name of cn=myname
, ou=mygroup
, o=mycompany
, c=mycountry
).
Requesting a Signed Certificate from a CA
Note:
Generating the key pair created a self-signed certificate; however, a certificate is more likely to be trusted by others when it is signed by a CA.
To get a CA signature, complete the following process:
-
Generate a CSR:
keytool -certreq -file myname.csr
This creates a CSR for the entity identified by the default alias
mykey
and puts the request in the file namedmyname.csr
. -
Submit
myname.csr
to a CA, such as DigiCert.
The CA authenticates you, the requestor (usually offline), and returns a certificate, signed by them, authenticating your public key. In some cases, the CA returns a chain of certificates, each one authenticating the public key of the signer of the previous certificate in the chain.
Importing a Certificate for the CA
To import a certificate for the CA, complete the following process:
-
Before you import the certificate reply from a CA, you need one or more trusted certificates either in your keystore or in the
cacerts
keystore file. See-importcert
in Commands.-
If the certificate reply is a certificate chain, then you need the top certificate of the chain. The root CA certificate that authenticates the public key of the CA.
-
If the certificate reply is a single certificate, then you need a certificate for the issuing CA (the one that signed it). If that certificate isn’t self-signed, then you need a certificate for its signer, and so on, up to a self-signed root CA certificate.
The
cacerts
keystore ships with a set of root certificates issued by the CAs of the Oracle Java Root Certificate program. If you request a signed certificate from a CA, and a certificate authenticating that CA's public key hasn't been added tocacerts
, then you must import a certificate from that CA as a trusted certificate.A certificate from a CA is usually self-signed or signed by another CA. If it is signed by another CA, you need a certificate that authenticates that CA's public key.
For example, you have obtained a
X.cer
file from a company that is a CA and the file is supposed to be a self-signed certificate that authenticates that CA's public key. Before you import it as a trusted certificate, you should ensure that the certificate is valid by:-
Viewing it with the
keytool -printcert
command or thekeytool -importcert
command without using the-noprompt
option. Make sure that the displayed certificate fingerprints match the expected fingerprints. -
Calling the person who sent the certificate, and comparing the fingerprints that you see with the ones that they show or that a secure public key repository shows.
Only when the fingerprints are equal is it assured that the certificate wasn’t replaced in transit with somebody else's certificate (such as an attacker’s certificate). If such an attack takes place, and you didn’t check the certificate before you imported it, then you would be trusting anything that the attacker signed.
-
-
Replace the self-signed certificate with a certificate chain, where each certificate in the chain authenticates the public key of the signer of the previous certificate in the chain, up to a root CA.
If you trust that the certificate is valid, then you can add it to your keystore by entering the following command:
keytool -importcert -alias alias -file X.cer
This command creates a trusted certificate entry in the keystore from the data in the CA certificate file and assigns the values of the
alias
to the entry.
Importing the Certificate Reply from the CA
After you import a certificate that authenticates the public key of the CA that you submitted your certificate signing request to (or there is already such a certificate in the cacerts
file), you can import the certificate reply and replace your self-signed certificate with a certificate chain.
-
Returned by the CA when the CA reply is a chain.
-
Constructed when the CA reply is a single certificate. This certificate chain is constructed by using the certificate reply and trusted certificates available either in the keystore where you import the reply or in the
cacerts
keystore file.
For example, if you sent your certificate signing request to DigiCert, then you can import their reply by entering the following command:
Note:
In this example, the returned certificate is named DCmyname.cer
.
keytool -importcert -trustcacerts -file DCmyname.cer
Exporting a Certificate That Authenticates the Public Key
Note:
If you used the jarsigner
command to sign a Java Archive (JAR) file, then clients that use the file will want to authenticate your signature.
One way that clients can authenticate you is by importing your public key certificate into their keystore as a trusted entry. You can then export the certificate and supply it to your clients.
For example:
-
Copy your certificate to a file named
myname.cer
by entering the following command:Note:
In this example, the entry has an alias of
mykey
.keytool -exportcert -alias mykey -file myname.cer
-
With the certificate and the signed JAR file, a client can use the
jarsigner
command to authenticate your signature.
Importing the Keystore
Use the importkeystore
command to import an entire keystore into another keystore. This imports all entries from the source keystore, including keys and certificates, to the destination keystore with a single command. You can use this command to import entries from a different type of keystore. During the import, all new entries in the destination keystore will have the same alias names and protection passwords (for secret keys and private keys). If the keytool
command can’t recover the private keys or secret keys from the source keystore, then it prompts you for a password. If it detects alias duplication, then it asks you for a new alias, and you can specify a new alias or simply allow the keytool
command to overwrite the existing one.
For example, import entries from a typical JKS type keystore key.jks
into a PKCS #11 type hardware-based keystore, by entering the following command:
keytool -importkeystore
-srckeystore key.jks -destkeystore NONE
-srcstoretype JKS -deststoretype PKCS11
-srcstorepass passwd
-deststorepass passwd
The importkeystore
command can also be used to import a single entry from a source keystore to a destination keystore. In this case, besides the options you used in the previous example, you need to specify the alias you want to import. With the -srcalias
option specified, you can also specify the destination alias name, protection password for a secret or private key, and the destination protection password you want as follows:
keytool -importkeystore
-srckeystore key.jks -destkeystore NONE
-srcstoretype JKS -deststoretype PKCS11
-srcstorepass passwd
-deststorepass passwd
-srcalias myprivatekey -destalias myoldprivatekey
-srckeypass passwd
-destkeypass passwd
-noprompt
Generating Certificates for an SSL Server
The following are keytool
commands used to generate key pairs and certificates for three entities:
-
Root CA (
root
) -
Intermediate CA (
ca
) -
SSL server (
server
)
Ensure that you store all the certificates in the same keystore. In the following examples, RSA is the recommended the key algorithm.
keytool -genkeypair -keystore root.jks -alias root -ext bc:c
keytool -genkeypair -keystore ca.jks -alias ca -ext bc:c
keytool -genkeypair -keystore server.jks -alias server
keytool -keystore root.jks -alias root -exportcert -rfc > root.pem
keytool -storepass passwd -keystore ca.jks -certreq -alias ca |
keytool -storepass passwd -keystore root.jks
-gencert -alias root -ext BC=0 -rfc > ca.pem
keytool -keystore ca.jks -importcert -alias ca -file ca.pem
keytool -storepass passwd -keystore server.jks -certreq -alias server |
keytool -storepass passwd -keystore ca.jks -gencert -alias ca
-ext ku:c=dig,kE -rfc > server.pem
cat root.pem ca.pem server.pem |
keytool -keystore server.jks -importcert -alias server
Terms
- Keystore
-
A keystore is a storage facility for cryptographic keys and certificates.
- Keystore entries
-
Keystores can have different types of entries. The two most applicable entry types for the
keytool
command include the following:Key entries: Each entry holds very sensitive cryptographic key information, which is stored in a protected format to prevent unauthorized access. Typically, a key stored in this type of entry is a secret key, or a private key accompanied by the certificate chain for the corresponding public key. See Certificate Chains. The
keytool
command can handle both types of entries, while thejarsigner
tool only handles the latter type of entry, that is private keys and their associated certificate chains.Trusted certificate entries: Each entry contains a single public key certificate that belongs to another party. The entry is called a trusted certificate because the keystore owner trusts that the public key in the certificate belongs to the identity identified by the subject (owner) of the certificate. The issuer of the certificate vouches for this, by signing the certificate.
- Keystore aliases
-
All keystore entries (key and trusted certificate entries) are accessed by way of unique aliases.
An alias is specified when you add an entity to the keystore with the
-genseckey
command to generate a secret key, the-genkeypair
command to generate a key pair (public and private key), or the-importcert
command to add a certificate or certificate chain to the list of trusted certificates. Subsequentkeytool
commands must use this same alias to refer to the entity.For example, you can use the alias
duke
to generate a new public/private key pair and wrap the public key into a self-signed certificate with the following command. See Certificate Chains.keytool -genkeypair -alias duke -keypass passwd
This example specifies an initial
passwd
required by subsequent commands to access the private key associated with the aliasduke
. If you later want to change Duke's private key password, use a command such as the following:keytool -keypasswd -alias duke -keypass passwd -new newpasswd
This changes the initial
passwd
tonewpasswd
. A password shouldn’t be specified on a command line or in a script unless it is for testing purposes, or you are on a secure system. If you don’t specify a required password option on a command line, then you are prompted for it. - Keystore implementation
-
The
KeyStore
class provided in thejava.security
package supplies well-defined interfaces to access and modify the information in a keystore. It is possible for there to be multiple different concrete implementations, where each implementation is that for a particular type of keystore.Currently, two command-line tools (
keytool
andjarsigner
) make use of keystore implementations. Because theKeyStore
class ispublic
, users can write additional security applications that use it.In JDK 9 and later, the default keystore implementation is
PKCS12
. This is a cross platform keystore based on the RSA PKCS12 Personal Information Exchange Syntax Standard. This standard is primarily meant for storing or transporting a user's private keys, certificates, and miscellaneous secrets. There is another built-in implementation, provided by Oracle. It implements the keystore as a file with a proprietary keystore type (format) namedJKS
. It protects each private key with its individual password, and also protects the integrity of the entire keystore with a (possibly different) password.Keystore implementations are provider-based. More specifically, the application interfaces supplied by
KeyStore
are implemented in terms of a Service Provider Interface (SPI). That is, there is a corresponding abstractKeystoreSpi
class, also in thejava.security package
, which defines the Service Provider Interface methods that providers must implement. The term provider refers to a package or a set of packages that supply a concrete implementation of a subset of services that can be accessed by the Java Security API. To provide a keystore implementation, clients must implement a provider and supply aKeystoreSpi
subclass implementation, as described in Steps to Implement and Integrate a Provider.Applications can choose different types of keystore implementations from different providers, using the
getInstance
factory method supplied in theKeyStore
class. A keystore type defines the storage and data format of the keystore information, and the algorithms used to protect private/secret keys in the keystore and the integrity of the keystore. Keystore implementations of different types aren’t compatible.The
keytool
command works on any file-based keystore implementation. It treats the keystore location that is passed to it at the command line as a file name and converts it to aFileInputStream
, from which it loads the keystore information.)Thejarsigner
commands can read a keystore from any location that can be specified with a URL.For
keytool
andjarsigner
, you can specify a keystore type at the command line, with the-storetype
option.If you don’t explicitly specify a keystore type, then the tools choose a keystore implementation based on the value of the
keystore.type
property specified in the security properties file. The security properties file is calledjava.security
, and resides in the security properties directory:-
Oracle Solaris, Linux, and macOS:
java.home/lib/security
-
Windows:
java.home\lib\security
Each tool gets the
keystore.type
value and then examines all the currently installed providers until it finds one that implements a keystores of that type. It then uses the keystore implementation from that provider.TheKeyStore
class defines a static method namedgetDefaultType
that lets applications retrieve the value of thekeystore.type
property. The following line of code creates an instance of the default keystore type as specified in thekeystore.type
property:KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
The default keystore type is
pkcs12
, which is a cross-platform keystore based on the RSA PKCS12 Personal Information Exchange Syntax Standard. This is specified by the following line in the security properties file:keystore.type=pkcs12
To have the tools utilize a keystore implementation other than the default, you can change that line to specify a different keystore type. For example, if you want to use the Oracle's
jks
keystore implementation, then change the line to the following:keystore.type=jks
Note:
Case doesn’t matter in keystore type designations. For example,
JKS
would be considered the same asjks
. -
- Certificate
-
A certificate (or public-key certificate) is a digitally signed statement from one entity (the issuer), saying that the public key and some other information of another entity (the subject) has some specific value. The following terms are related to certificates:
-
Public Keys: These are numbers associated with a particular entity, and are intended to be known to everyone who needs to have trusted interactions with that entity. Public keys are used to verify signatures.
-
Digitally Signed: If some data is digitally signed, then it is stored with the identity of an entity and a signature that proves that entity knows about the data. The data is rendered unforgeable by signing with the entity's private key.
-
Identity: A known way of addressing an entity. In some systems, the identity is the public key, and in others it can be anything from an Oracle Solaris UID to an email address to an X.509 distinguished name.
-
Signature: A signature is computed over some data using the private key of an entity. The signer, which in the case of a certificate is also known as the issuer.
-
Private Keys: These are numbers, each of which is supposed to be known only to the particular entity whose private key it is (that is, it is supposed to be kept secret). Private and public keys exist in pairs in all public key cryptography systems (also referred to as public key crypto systems). In a typical public key crypto system, such as DSA, a private key corresponds to exactly one public key. Private keys are used to compute signatures.
-
Entity: An entity is a person, organization, program, computer, business, bank, or something else you are trusting to some degree.
Public key cryptography requires access to users' public keys. In a large-scale networked environment, it is impossible to guarantee that prior relationships between communicating entities were established or that a trusted repository exists with all used public keys. Certificates were invented as a solution to this public key distribution problem. Now a Certification Authority (CA) can act as a trusted third party. CAs are entities such as businesses that are trusted to sign (issue) certificates for other entities. It is assumed that CAs only create valid and reliable certificates because they are bound by legal agreements. There are many public Certification Authorities, such as DigiCert, Comodo, Entrust, and so on.
You can also run your own Certification Authority using products such as Microsoft Certificate Server or the Entrust CA product for your organization. With the
keytool
command, it is possible to display, import, and export certificates. It is also possible to generate self-signed certificates.The
keytool
command currently handles X.509 certificates. -
- X.509 Certificates
-
The X.509 standard defines what information can go into a certificate and describes how to write it down (the data format). All the data in a certificate is encoded with two related standards called ASN.1/DER. Abstract Syntax Notation 1 describes data. The Definite Encoding Rules describe a single way to store and transfer that data.
All X.509 certificates have the following data, in addition to the signature:
-
Version: This identifies which version of the X.509 standard applies to this certificate, which affects what information can be specified in it. Thus far, three versions are defined. The
keytool
command can import and export v1, v2, and v3 certificates. It generates v3 certificates.-
X.509 Version 1 has been available since 1988, is widely deployed, and is the most generic.
-
X.509 Version 2 introduced the concept of subject and issuer unique identifiers to handle the possibility of reuse of subject or issuer names over time. Most certificate profile documents strongly recommend that names not be reused and that certificates shouldn’t make use of unique identifiers. Version 2 certificates aren’t widely used.
-
X.509 Version 3 is the most recent (1996) and supports the notion of extensions where anyone can define an extension and include it in the certificate. Some common extensions are: KeyUsage (limits the use of the keys to particular purposes such as
signing-only
) and AlternativeNames (allows other identities to also be associated with this public key, for example. DNS names, email addresses, IP addresses). Extensions can be marked critical to indicate that the extension should be checked and enforced or used. For example, if a certificate has the KeyUsage extension marked critical and set tokeyCertSign
, then when this certificate is presented during SSL communication, it should be rejected because the certificate extension indicates that the associated private key should only be used for signing certificates and not for SSL use.
-
-
Serial number: The entity that created the certificate is responsible for assigning it a serial number to distinguish it from other certificates it issues. This information is used in numerous ways. For example, when a certificate is revoked its serial number is placed in a Certificate Revocation List (CRL).
-
Signature algorithm identifier: This identifies the algorithm used by the CA to sign the certificate.
-
Issuer name: The X.500 Distinguished Name of the entity that signed the certificate. This is typically a CA. Using this certificate implies trusting the entity that signed this certificate. In some cases, such as root or top-level CA certificates, the issuer signs its own certificate.
-
Validity period: Each certificate is valid only for a limited amount of time. This period is described by a start date and time and an end date and time, and can be as short as a few seconds or almost as long as a century. The validity period chosen depends on a number of factors, such as the strength of the private key used to sign the certificate, or the amount one is willing to pay for a certificate. This is the expected period that entities can rely on the public value, when the associated private key has not been compromised.
-
Subject name: The name of the entity whose public key the certificate identifies. This name uses the X.500 standard, so it is intended to be unique across the Internet. This is the X.500 Distinguished Name (DN) of the entity. For example,
CN=cName, OU=orgUnit, O=org, C=countryCode
These refer to the subject's common name (CN), organizational unit (OU), organization (O), and country (C).
-
Subject public key information: This is the public key of the entity being named with an algorithm identifier that specifies which public key crypto system this key belongs to and any associated key parameters.
-
- Certificate Chains
-
The
keytool
command can create and manage keystore key entries that each contain a private key and an associated certificate chain. The first certificate in the chain contains the public key that corresponds to the private key.When keys are first generated, the chain starts off containing a single element, a self-signed certificate. See -genkeypair in Commands. A self-signed certificate is one for which the issuer (signer) is the same as the subject. The subject is the entity whose public key is being authenticated by the certificate. Whenever the
-genkeypair
command is called to generate a new public/private key pair, it also wraps the public key into a self-signed certificate.Later, after a Certificate Signing Request (CSR) was generated with the
-certreq
command and sent to a Certification Authority (CA), the response from the CA is imported with-importcert
, and the self-signed certificate is replaced by a chain of certificates. At the bottom of the chain is the certificate (reply) issued by the CA authenticating the subject's public key. The next certificate in the chain is one that authenticates the CA's public key.In many cases, this is a self-signed certificate, which is a certificate from the CA authenticating its own public key, and the last certificate in the chain. In other cases, the CA might return a chain of certificates. In this case, the bottom certificate in the chain is the same (a certificate signed by the CA, authenticating the public key of the key entry), but the second certificate in the chain is a certificate signed by a different CA that authenticates the public key of the CA you sent the CSR to. The next certificate in the chain is a certificate that authenticates the second CA's key, and so on, until a self-signed root certificate is reached. Each certificate in the chain (after the first) authenticates the public key of the signer of the previous certificate in the chain.
Many CAs only return the issued certificate, with no supporting chain, especially when there is a flat hierarchy (no intermediates CAs). In this case, the certificate chain must be established from trusted certificate information already stored in the keystore.
A different reply format (defined by the PKCS #7 standard) includes the supporting certificate chain in addition to the issued certificate. Both reply formats can be handled by the
keytool
command.The top-level (root) CA certificate is self-signed. However, the trust into the root's public key doesn’t come from the root certificate itself, but from other sources such as a newspaper. This is because anybody could generate a self-signed certificate with the distinguished name of, for example, the DigiCert root CA. The root CA public key is widely known. The only reason it is stored in a certificate is because this is the format understood by most tools, so the certificate in this case is only used as a vehicle to transport the root CA's public key. Before you add the root CA certificate to your keystore, you should view it with the
-printcert
option and compare the displayed fingerprint with the well-known fingerprint obtained from a newspaper, the root CA's Web page, and so on. - cacerts Certificates File
-
A certificates file named
cacerts
resides in the security properties directory:-
Oracle Solaris, Linux, and macOS:
JAVA_HOME/lib/security
-
Windows:
java.home\lib\security
java.home
is the runtime environment directory, which is thejre
directory in the JDK or the top-level directory of the Java Runtime Environment (JRE).The
cacerts
file represents a system-wide keystore with CA certificates. System administrators can configure and manage that file with thekeytool
command by specifyingjks
as the keystore type. Thecacerts
keystore file ships with a default set of root CA certificates. For Oracle Solaris, Linux, OS X, and Windows, you can list the default certificates with the following command:keytool -list -cacerts
System administrators must change the initial password and the default access permission of the
cacerts
keystore file upon installing the SDK.Note:
It is important to verify your
cacerts
file. Because you trust the CAs in thecacerts
file as entities for signing and issuing certificates to other entities, you must manage thecacerts
file carefully. Thecacerts
file should contain only certificates of the CAs you trust. It is your responsibility to verify the trusted root CA certificates bundled in thecacerts
file and make your own trust decisions.To remove an untrusted CA certificate from the
cacerts
file, use the-delete
option of thekeytool
command. You can find thecacerts
file in the JRE installation directory. Contact your system administrator if you don’t have permission to edit this file -
- Internet RFC 1421 Certificate Encoding Standard
-
Certificates are often stored using the printable encoding format defined by the Internet RFC 1421 standard, instead of their binary encoding. This certificate format, also known as Base64 encoding, makes it easy to export certificates to other applications by email or through some other mechanism.
Certificates read by the
-importcert
and-printcert
commands can be in either this format or binary encoded. The-exportcert
command by default outputs a certificate in binary encoding, but will instead output a certificate in the printable encoding format, when the-rfc
option is specified.The
-list
command by default prints the SHA-256 fingerprint of a certificate. If the-v
option is specified, then the certificate is printed in human-readable format. If the-rfc
option is specified, then the certificate is output in the printable encoding format.In its printable encoding format, the encoded certificate is bounded at the beginning and end by the following text:
-----BEGIN CERTIFICATE----- encoded certificate goes here. -----END CERTIFICATE-----
- X.500 Distinguished Names
-
X.500 Distinguished Names are used to identify entities, such as those that are named by the
subject
andissuer
(signer) fields of X.509 certificates. Thekeytool
command supports the following subparts:-
commonName: The common name of a person.
-
organizationUnit: The small organization (such as department or division) name. For example, Purchasing.
-
localityName: The locality (city) name. For example, Palo Alto.
-
stateName: State or province name. For example, California.
-
country: Two-letter country code. For example, CH.
When you supply a distinguished name string as the value of a
-dname
option, such as for the-genkeypair
command, the string must be in the following format:CN=cName, OU=orgUnit, O=org, L=city, S=state, C=countryCode
All the following items represent actual values and the previous keywords are abbreviations for the following:
CN=commonName OU=organizationUnit O=organizationName L=localityName S=stateName C=country
A sample distinguished name string is:
CN=commonName, OU=organizationUnit, O=organizationName, L=localityName, S=stateName, C=country
A sample command using such a string is:
keytool -genkeypair -dname "CN=commonName, OU=organizationUnit, O=organizationName, L=localityName, S=stateName, C=country" -alias mark
Case doesn’t matter for the keyword abbreviations. For example, CN, cn, and Cn are all treated the same.
Order matters; each subcomponent must appear in the designated order. However, it isn’t necessary to have all the subcomponents. You can use a subset, for example:
CN=commonName, OU=organizationUnit, O=organizationName, C=country
If a distinguished name string value contains a comma, then the comma must be escaped by a backslash (\) character when you specify the string on a command line, as in:
cn=commonName, ou=organizationUnit\, department, o=organizationName, c=country
It is never necessary to specify a distinguished name string on a command line. When the distinguished name is needed for a command, but not supplied on the command line, the user is prompted for each of the subcomponents. In this case, a comma doesn’t need to be escaped by a backslash (\).
-
Warnings
Importing Trusted Certificates Warning
Important: Be sure to check a certificate very carefully before importing it as a trusted certificate.
Windows Example:
View the certificate first with the -printcert
command or the -importcert
command without the -noprompt
option. Ensure that the displayed certificate fingerprints match the expected ones. For example, suppose someone sends or emails you a certificate that you put it in a file named \tmp\cert
. Before you consider adding the certificate to your list of trusted certificates, you can execute a -printcert
command to view its fingerprints, as follows:
keytool -printcert -file \tmp\cert
Owner: CN=ll, OU=ll, O=ll, L=ll, S=ll, C=ll
Issuer: CN=ll, OU=ll, O=ll, L=ll, S=ll, C=ll
Serial Number: 59092b34
Valid from: Thu Jun 24 18:01:13 PDT 2016 until: Wed Jun 23 17:01:13 PST 2016
Certificate Fingerprints:
SHA-1: 20:B6:17:FA:EF:E5:55:8A:D0:71:1F:E8:D6:9D:C0:37:13:0E:5E:FE
SHA-256: 90:7B:70:0A:EA:DC:16:79:92:99:41:FF:8A:FE:EB:90:
17:75:E0:90:B2:24:4D:3A:2A:16:A6:E4:11:0F:67:A4
Oracle Solaris Example:
View the certificate first with the -printcert
command or the -importcert
command without the -noprompt
option. Ensure that the displayed certificate fingerprints match the expected ones. For example, suppose someone sends or emails you a certificate that you put it in a file named /tmp/cert
. Before you consider adding the certificate to your list of trusted certificates, you can execute a -printcert
command to view its fingerprints, as follows:
keytool -printcert -file /tmp/cert
Owner: CN=ll, OU=ll, O=ll, L=ll, S=ll, C=ll
Issuer: CN=ll, OU=ll, O=ll, L=ll, S=ll, C=ll
Serial Number: 59092b34
Valid from: Thu Jun 24 18:01:13 PDT 2016 until: Wed Jun 23 17:01:13 PST 2016
Certificate Fingerprints:
SHA-1: 20:B6:17:FA:EF:E5:55:8A:D0:71:1F:E8:D6:9D:C0:37:13:0E:5E:FE
SHA-256: 90:7B:70:0A:EA:DC:16:79:92:99:41:FF:8A:FE:EB:90:
17:75:E0:90:B2:24:4D:3A:2A:16:A6:E4:11:0F:67:A4
Then call or otherwise contact the person who sent the certificate and compare the fingerprints that you see with the ones that they show. Only when the fingerprints are equal is it guaranteed that the certificate wasn’t replaced in transit with somebody else's certificate such as an attacker's certificate. If such an attack took place, and you didn’t check the certificate before you imported it, then you would be trusting anything the attacker signed, for example, a JAR file with malicious class files inside.
Note:
It isn’t required that you execute a -printcert
command before importing a certificate. This is because before you add a certificate to the list of trusted certificates in the keystore, the -importcert
command prints out the certificate information and prompts you to verify it. You can then stop the import operation. However, you can do this only when you call the -importcert
command without the -noprompt
option. If the -noprompt
option is specified, then there is no interaction with the user.
Passwords Warning
Most commands that operate on a keystore require the store password. Some commands require a private/secret key password. Passwords can be specified on the command line in the -storepass
and -keypass
options. However, a password shouldn’t be specified on a command line or in a script unless it is for testing, or you are on a secure system. When you don’t specify a required password option on a command line, you are prompted for it.
Certificate Conformance Warning
Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile defined a profile on conforming X.509 certificates, which includes what values and value combinations are valid for certificate fields and extensions.
The keytool
command doesn’t enforce all of these rules so it can generate certificates that don’t conform to the standard, such as self-signed certificates that would be used for internal testing purposes. Certificates that don’t conform to the standard might be rejected by JRE or other applications. Users should ensure that they provide the correct options for -dname
, -ext
, and so on.
Import a New Trusted Certificate
Before you add the certificate to the keystore, the keytool
command verifies it by attempting to construct a chain of trust from that certificate to a self-signed certificate (belonging to a root CA), using trusted certificates that are already available in the keystore.
If the -trustcacerts
option was specified, then additional certificates are considered for the chain of trust, namely the certificates in a file named cacerts
.
If the keytool
command fails to establish a trust path from the certificate to be imported up to a self-signed certificate (either from the keystore or the cacerts
file), then the certificate information is printed, and the user is prompted to verify it by comparing the displayed certificate fingerprints with the fingerprints obtained from some other (trusted) source of information, which might be the certificate owner. Be very careful to ensure the certificate is valid before importing it as a trusted certificate. The user then has the option of stopping the import operation. If the -noprompt
option is specified, then there is no interaction with the user.
Import a Certificate Reply
When you import a certificate reply, the certificate reply is validated with trusted certificates from the keystore, and optionally, the certificates configured in the cacerts
keystore file when the -trustcacerts
option is specified.
The methods of determining whether the certificate reply is trusted are as follows:
-
If the reply is a single X.509 certificate, then the
keytool
command attempts to establish a trust chain, starting at the certificate reply and ending at a self-signed certificate (belonging to a root CA). The certificate reply and the hierarchy of certificates is used to authenticate the certificate reply from the new certificate chain of aliases. If a trust chain can’t be established, then the certificate reply isn’t imported. In this case, thekeytool
command doesn’t print the certificate and prompt the user to verify it, because it is very difficult for a user to determine the authenticity of the certificate reply. -
If the reply is a PKCS #7 formatted certificate chain or a sequence of X.509 certificates, then the chain is ordered with the user certificate first followed by zero or more CA certificates. If the chain ends with a self-signed root CA certificate and the
-trustcacerts
option was specified, thekeytool
command attempts to match it with any of the trusted certificates in the keystore or thecacerts
keystore file. If the chain doesn’t end with a self-signed root CA certificate and the-trustcacerts
option was specified, thekeytool
command tries to find one from the trusted certificates in the keystore or thecacerts
keystore file and add it to the end of the chain. If the certificate isn’t found and the-noprompt
option isn’t specified, the information of the last certificate in the chain is printed, and the user is prompted to verify it.
If the public key in the certificate reply matches the user's public key already stored with alias
, then the old certificate chain is replaced with the new certificate chain in the reply. The old chain can only be replaced with a valid keypass
, and so the password used to protect the private key of the entry is supplied. If no password is provided, and the private key password is different from the keystore password, the user is prompted for it.
This command was named -import
in earlier releases. This old name is still supported in this release. The new name, -importcert
, is preferred.
Example of Using a Pre-Configured Options File
You can use a file named
preconfig
as a pre-configured options file.
# A tiny pre-configured options file
keytool.all = -keystore ${user.home}/ks
keytool.list = -v
keytool.genkeypair = -keyalg rsa
Running keytool -conf preconfig -list
is identical to
keytool -keystore ~/ks
-v -list
Running keytool -conf preconfig
-genkeypair -alias me
is identical to
keytool -keystore ~/ks -keyalg rsa -genkeypair -alias
me
keytool -conf preconfig -genkeypair -alias you
-keyalg ec
is identical to
keytool -keystore ~/ks -keyalg rsa -genkeypair -alias you
-keyalg ec
which is equivalent to
keytool -keystore ~/ks -genkeypair -alias me
-keyalg ec