jarsigner - JAR Signing and Verification Tool

Generates signatures for Java ARchive (JAR) files, and verifies the signatures of signed JAR files.

SYNOPSIS

jarsigner [ options ] jar-file alias
jarsigner -verify [ options ] jar-file [alias...]

The jarsigner -verify command can take zero or more keystore alias names after the jar filename. When specified, jarsigner will check that the certificate used to verify each signed entry in the jar file matches one of the keystore aliases. The aliases are defined in the keystore specified by -keystore, or the default keystore.

DESCRIPTION

The jarsigner tool is used for two purposes:

  1. to sign Java ARchive (JAR) files, and
  2. to verify the signatures and integrity of signed JAR files.

The JAR feature enables the packaging of class files, images, sounds, and other digital data in a single file for faster and easier distribution. A tool named jar enables developers to produce JAR files. (Technically, any zip file can also be considered a JAR file, although when created by jar or processed by jarsigner, JAR files also contain a META-INF/MANIFEST.MF file.)

A digital signature is a string of bits that is computed from some data (the data being "signed") and the private key of an entity (a person, company, etc.). Like a handwritten signature, a digital signature has many useful characteristics:

In order for an entity's signature to be generated for a file, the entity must first have a public/private key pair associated with it, and also one or more certificates authenticating its public key. A certificate is a digitally signed statement from one entity, saying that the public key of some other entity has a particular value.

jarsigner uses key and certificate information from a keystore to generate digital signatures for JAR files. A keystore is a database of private keys and their associated X.509 certificate chains authenticating the corresponding public keys. The keytool utility is used to create and administer keystores.

jarsigner uses an entity's private key to generate a signature. The signed JAR file contains, among other things, a copy of the certificate from the keystore for the public key corresponding to the private key used to sign the file. jarsigner can verify the digital signature of the signed JAR file using the certificate inside it (in its signature block file).

jarsigner can generate signatures that include a timestamp, thus enabling systems/deployer (including Java Plug-in) to check whether the JAR file was signed while the signing certificate was still valid. In addition, APIs will allow applications to obtain the timestamp information.

At this time, jarsigner can only sign JAR files created by the SDK jar tool or zip files. (JAR files are the same as zip files, except they also have a META-INF/MANIFEST.MF file. Such a file will automatically be created when jarsigner signs a zip file.)

The default jarsigner behavior is to sign a JAR (or zip) file. Use the -verify option to instead have it verify a signed JAR file.

The jarsigner command also attempts to validate the signer's certificate after signing or verifying. If there is a validation error or any other problem, the command generates warning messages. If you specify the -strict option, then the command treats severe warnings as errors. See ERRORS AND WARNINGS.

Keystore Aliases

All keystore entities are accessed via unique aliases.

When using jarsigner to sign a JAR file, you must specify the alias for the keystore entry containing the private key needed to generate the signature. For example, the following will sign the JAR file named "MyJARFile.jar", using the private key associated with the alias "duke" in the keystore named "mystore" in the "working" directory. Since no output file is specified, it overwrites MyJARFile.jar with the signed JAR file.

    jarsigner -keystore /working/mystore -storepass <keystore password>
      -keypass <private key password> MyJARFile.jar duke

Keystores are protected with a password, so the store password must be specified. You will be prompted for it if you don't specify it on the command line. Similarly, private keys are protected in a keystore with a password, so the private key's password must be specified, and you will be prompted for it if you don't specify it on the command line and it isn't the same as the store password.

Keystore Location

jarsigner has a -keystore option for specifying the URL of the keystore to be used. The keystore is by default stored in a file named .keystore in the user's home directory, as determined by the user.home system property. On Solaris systems user.home defaults to the user's home directory.

Note that the input stream from the -keystore option is passed to the KeyStore.load method. If NONE is specified as the URL, then a null stream is passed to the KeyStore.load method. NONE should be specified if the KeyStore is not file-based, for example, if it resides on a hardware token device.

Keystore Implementation

The KeyStore class provided in the java.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, there are two command-line tools that make use of keystore implementations (keytool and jarsigner), and also a GUI-based tool named Policy Tool. Since KeyStore is publicly available, JDK users can write additional security applications that use it.

There is a built-in default implementation, provided by Oracle. It implements the keystore as a file, utilizing a proprietary keystore type (format) named "JKS". 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 abstract KeystoreSpi class, also in the java.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.) Thus, to provide a keystore implementation, clients must implement a provider and supply a KeystoreSpi subclass implementation, as described in How to Implement a Provider for the Java Cryptography Architecture.

Applications can choose different types of keystore implementations from different providers, using the "getInstance" factory method supplied in the KeyStore class. A keystore type defines the storage and data format of the keystore information, and the algorithms used to protect private keys in the keystore and the integrity of the keystore itself. Keystore implementations of different types are not compatible.

keytool works on any file-based keystore implementation. (It treats the keystore location that is passed to it at the command line as a filename and converts it to a FileInputStream, from which it loads the keystore information.) The jarsigner and policytool tools, on the other hand, can read a keystore from any location that can be specified using a URL.

For jarsigner and keytool, you can specify a keystore type at the command line, via the -storetype option. For Policy Tool, you can specify a keystore type via the "Change Keystore" command in the Edit menu.

If you don't explicitly specify a keystore type, the tools choose a keystore implementation based simply on the value of the keystore.type property specified in the security properties file. The security properties file is called java.security, and it resides in the SDK security properties directory, java.home/lib/security, where java.home is the runtime environment's directory (the jre directory in the SDK or the top-level directory of the JRE).

Each tool gets the keystore.type value and then examines all the currently-installed providers until it finds one that implements keystores of that type. It then uses the keystore implementation from that provider.

The KeyStore class defines a static method named getDefaultType that lets applications and applets retrieve the value of the keystore.type property. The following line of code creates an instance of the default keystore type (as specified in the keystore.type property):

    KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());

The default keystore type is "jks" (the proprietary type of the keystore implementation provided by Oracle). This is specified by the following line in the security properties file:

    keystore.type=jks

Note: Case doesn't matter in keystore type designations. For example, "JKS" would be considered the same as "jks".

To have the tools utilize a keystore implementation other than the default, change that line to specify a different keystore type. For example, if you have a provider package that supplies a keystore implementation for a keystore type called "pkcs12", change the line to

    keystore.type=pkcs12

Note that if you us the PKCS#11 provider package, you should refer to the KeyTool and JarSigner section of the Java PKCS#11 Reference Guide for details.

Supported Algorithms

By default, jarsigner signs a JAR file using one of the following:

That is, if the signer's public and private keys are DSA keys, jarsigner will sign the JAR file using the "SHA1withDSA" algorithm. If the signer's keys are RSA keys, jarsigner will attempt to sign the JAR file using the "SHA256withRSA" algorithm. If the signer's keys are EC keys, jarsigner will sign the JAR file using the "SHA256withECDSA" algorithm.

These default signature algorithms can be overridden using the -sigalg option.

The Signed JAR File

When jarsigner is used to sign a JAR file, the output signed JAR file is exactly the same as the input JAR file, except that it has two additional files placed in the META-INF directory:

The base file names for these two files come from the value of the -sigFile option. For example, if the option appears as

-sigFile MKSIGN

The files are named "MKSIGN.SF" and "MKSIGN.DSA".

If no -sigfile option appears on the command line, the base file name for the .SF and .DSA files will be the first 8 characters of the alias name specified on the command line, all converted to upper case. If the alias name has fewer than 8 characters, the full alias name is used. If the alias name contains any characters that are not allowed in a signature file name, each such character is converted to an underscore ("_") character in forming the file name. Legal characters include letters, digits, underscores, and hyphens.

The Signature (.SF) File

A signature file (the .SF file) looks similar to the manifest file that is always included in a JAR file when jarsigner is used to sign the file. That is, for each source file included in the JAR file, the .SF file has three lines, just as in the manifest file, listing the following:

In the manifest file, the SHA digest value for each source file is the digest (hash) of the binary data in the source file. In the .SF file, on the other hand, the digest value for a given source file is the hash of the three lines in the manifest file for the source file.

The signature file also, by default, includes a header containing a hash of the whole manifest file. The presence of the header enables verification optimization, as described in JAR File Verification.

The Signature Block File

The .SF file is signed and the signature is placed in the signature block file. This file also contains, encoded inside it, the certificate or certificate chain from the keystore which authenticates the public key corresponding to the private key used for signing. The file has the extension .DSA, .RSA, or .EC depending on the digest algorithm used.

Signature Timestamp

jarsigner tool can generate and store a signature timestamp when signing a JAR file. In addition, jarsigner supports alternative signing mechanisms. This behavior is optional and is controlled by the user at the time of signing through these options:

Each of these options is detailed in the Options section below.

JAR File Verification

A successful JAR file verification occurs if the signature(s) are valid, and none of the files that were in the JAR file when the signatures were generated have been changed since then. JAR file verification involves the following steps:

  1. Verify the signature of the .SF file itself.

    That is, the verification ensures that the signature stored in each signature block (.DSA) file was in fact generated using the private key corresponding to the public key whose certificate (or certificate chain) also appears in the .DSA file. It also ensures that the signature is a valid signature of the corresponding signature (.SF) file, and thus the .SF file has not been tampered with.

  2. Verify the digest listed in each entry in the .SF file with each corresponding section in the manifest.

    The .SF file by default includes a header containing a hash of the entire manifest file. When the header is present, then the verification can check to see whether or not the hash in the header indeed matches the hash of the manifest file. If that is the case, verification proceeds to the next step.

    If that is not the case, a less optimized verification is required to ensure that the hash in each source file information section in the .SF file equals the hash of its corresponding section in the manifest file (see The Signature (.SF) File).

    One reason the hash of the manifest file that is stored in the .SF file header may not equal the hash of the current manifest file would be because one or more files were added to the JAR file (using the jar tool) after the signature (and thus the .SF file) was generated. When the jar tool is used to add files, the manifest file is changed (sections are added to it for the new files), but the .SF file is not. A verification is still considered successful if none of the files that were in the JAR file when the signature was generated have been changed since then, which is the case if the hashes in the non-header sections of the .SF file equal the hashes of the corresponding sections in the manifest file.

  3. Read each file in the JAR file that has an entry in the .SF file. While reading, compute the file's digest, and then compare the result with the digest for this file in the manifest section. The digests should be the same, or verification fails.

If any serious verification failures occur during the verification process, the process is stopped and a security exception is thrown. It is caught and displayed by jarsigner.

Note: You should read any addition warnings (or errors if you specified the -strict option), as well as the content of the certificate (by specifying the -verbose and -certs options) to determine if the signature can be trusted.

Multiple Signatures for a JAR File

A JAR file can be signed by multiple people simply by running the jarsigner tool on the file multiple times, specifying the alias for a different person each time, as in:

  jarsigner myBundle.jar susan
  jarsigner myBundle.jar kevin

When a JAR file is signed multiple times, there are multiple .SF and .DSA files in the resulting JAR file, one pair for each signature. Thus, in the example above, the output JAR file includes files with the following names:

  SUSAN.SF
  SUSAN.DSA
  KEVIN.SF
  KEVIN.DSA

Note: It is also possible for a JAR file to have mixed signatures, some generated by the JDK 1.1 javakey tool and others by jarsigner. That is, jarsigner can be used to sign JAR files already previously signed using javakey.

OPTIONS

The various jarsigner options are listed and described below. Note:

-keystore url
Specifies the URL that tells the keystore location. This defaults to the file .keystore in the user's home directory, as determined by the "user.home" system property.

A keystore is required when signing, so you must explicitly specify one if the default keystore does not exist (or you want to use one other than the default).

A keystore is not required when verifying, but if one is specified, or the default exists, and the -verbose option was also specified, additional information is output regarding whether or not any of the certificates used to verify the JAR file are contained in that keystore.

Note: the -keystore argument can actually be a file name (and path) specification rather than a URL, in which case it will be treated the same as a "file:" URL. That is,

  -keystore filePathAndName

is treated as equivalent to

  -keystore file:filePathAndName

If the Sun PKCS#11 provider has been configured in the java.security security properties file (located in the JRE's $JAVA_HOME/lib/security directory), then keytool and jarsigner can operate on the PKCS#11 token by specifying these options:

  • -keystore NONE
  • -storetype PKCS11

For example, this command lists the contents of the configured PKCS#11 token:

   jarsigner -keystore NONE -storetype PKCS11 -list

-storetype storetype
Specifies the type of keystore to be instantiated. The default keystore type is the one that is specified as the value of the "keystore.type" property in the security properties file, which is returned by the static getDefaultType method in java.security.KeyStore.

The PIN for a PCKS#11 token can also be specified using the -storepass option. If none has been specified, keytool and jarsigner will prompt for the token PIN. If the token has a protected authentication path (such as a dedicated PIN-pad or a biometric reader), then the -protected option must be specified and no password options can be specified.

-storepass[:env | :file] argument

Specifies the password which is required to access the keystore. This is only needed when signing (not verifying) a JAR file. In that case, if a -storepass option is not provided at the command line, the user is prompted for the password.

If the modifier env or file is not specified, then the password has the value argument. Otherwise, the password is retrieved as follows:

  • env: Retrieve the password from the environment variable named argument
  • file: Retrieve the password from the file named argument

Note: The password shouldn't be specified on the command line or in a script unless it is for testing purposes, or you are on a secure system.

-keypass[:env | :file] argument

Specifies the password used to protect the private key of the keystore entry addressed by the alias specified on the command line. The password is required when using jarsigner to sign a JAR file. If no password is provided on the command line, and the required password is different from the store password, the user is prompted for it.

If the modifier env or file is not specified, then the password has the value argument. Otherwise, the password is retrieved as follows:

  • env: Retrieve the password from the environment variable named argument
  • file: Retrieve the password from the file named argument

Note: The password shouldn't be specified on the command line or in a script unless it is for testing purposes, or you are on a secure system.

-sigfile file
Specifies the base file name to be used for the generated .SF and .DSA files. For example, if file is "DUKESIGN", the generated .SF and .DSA files will be named "DUKESIGN.SF" and "DUKESIGN.DSA", and will be placed in the "META-INF" directory of the signed JAR file.

The characters in file must come from the set "a-zA-Z0-9_-". That is, only letters, numbers, underscore, and hyphen characters are allowed. Note: All lowercase characters will be converted to uppercase for the .SF and .DSA file names.

If no -sigfile option appears on the command line, the base file name for the .SF and .DSA files will be the first 8 characters of the alias name specified on the command line, all converted to upper case. If the alias name has fewer than 8 characters, the full alias name is used. If the alias name contains any characters that are not legal in a signature file name, each such character is converted to an underscore ("_") character in forming the file name.

-sigalg algorithm
Specifies the name of the signature algorithm to use to sign the JAR file.

See Appendix A of the Java Cryptography Architecture for a list of standard signature algorithm names. This algorithm must be compatible with the private key used to sign the JAR file. If this option is not specified, SHA1withDSA, SHA256withRSA, or SHA256withECDSA will be used depending on the type of private key. There must either be a statically installed provider supplying an implementation of the specified algorithm or the user must specify one with the -providerClass option, otherwise the command will not succeed.

-digestalg algorithm
Specifies the name of the message digest algorithm to use when digesting the entries of a jar file.

See Appendix A of the Java Cryptography Architecture for a list of standard message digest algorithm names. If this option is not specified, SHA256 will be used. There must either be a statically installed provider supplying an implementation of the specified algorithm or the user must specify one with the -providerClass option, otherwise the command will not succeed.

-signedjar file
Specifies the name to be used for the signed JAR file.

If no name is specified on the command line, the name used is the same as the input JAR file name (the name of the JAR file to be signed); in other words, that file is overwritten with the signed JAR file.

-verify
If this appears on the command line, the specified JAR file will be verified, not signed. If the verification is successful, "jar verified" will be displayed. If you try to verify an unsigned JAR file, or a JAR file signed with an unsupported algorithm (e.g., RSA when you don't have an RSA provider installed), the following is displayed: "jar is unsigned. (signatures missing or not parsable)"

If you also specified the -strict option, and the jarsigner command detected severe warnings, the message, "jar verified, with signer errors" is displayed.

It is possible to verify JAR files signed using either jarsigner or the JDK 1.1 javakey tool, or both.

For further information on verification, see JAR File Verification.

-certs
If this appears on the command line, along with the -verify and -verbose options, the output includes certificate information for each signer of the JAR file. This information includes
  • the name of the type of certificate (stored in the .DSA file) that certifies the signer's public key
  • if the certificate is an X.509 certificate (more specifically, an instance of java.security.cert.X509Certificate): the distinguished name of the signer

The keystore is also examined. If no keystore value is specified on the command line, the default keystore file (if any) will be checked. If the public key certificate for a signer matches an entry in the keystore, then the following information will also be displayed:

  • in parentheses, the alias name for the keystore entry for that signer. If the signer actually comes from a JDK 1.1 identity database instead of from a keystore, the alias name will appear in brackets instead of parentheses.
-certchain file
Specifies the certificate chain to be used, if the certificate chain associated with the private key of the keystore entry, addressed by the alias specified on the command line, is not complete. This may happen if the keystore is located on a hardware token where there is not enough capacity to hold a complete certificate chain. The file can be a sequence of X.509 certificates concatenated together, or a single PKCS#7 formatted data block, either in binary encoding format or in printable encoding format (also known as BASE64 encoding) as defined by the Internet RFC 1421 standard.
-verbose
If this appears on the command line, it indicates "verbose" mode, which causes jarsigner to output extra information as to the progress of the JAR signing or verification.
-internalsf
In the past, the .DSA (signature block) file generated when a JAR file was signed used to include a complete encoded copy of the .SF file (signature file) also generated. This behavior has been changed. To reduce the overall size of the output JAR file, the .DSA file by default doesn't contain a copy of the .SF file anymore. But if -internalsf appears on the command line, the old behavior is utilized. This option is mainly useful for testing; in practice, it should not be used, since doing so eliminates a useful optimization.
-sectionsonly
If this appears on the command line, the .SF file (signature file) generated when a JAR file is signed does not include a header containing a hash of the whole manifest file. It just contains information and hashes related to each individual source file included in the JAR file, as described in The Signature (.SF) File .

By default, this header is added, as an optimization. When the header is present, then whenever the JAR file is verified, the verification can first check to see whether or not the hash in the header indeed matches the hash of the whole manifest file. If so, verification proceeds to the next step. If not, it is necessary to do a less optimized verification that the hash in each source file information section in the .SF file equals the hash of its corresponding section in the manifest file.

For further information, see JAR File Verification.

This option is mainly useful for testing; in practice, it should not be used, since doing so eliminates a useful optimization.

-protected
Either true or false. This value should be specified as true if a password must be given via a protected authentication path such as a dedicated PIN reader.
-providerClass provider-class-name
Used to specify the name of cryptographic service provider's master class file when the service provider is not listed in the security properties file, java.security.

Used in conjunction with the -providerArg ConfigFilePath option, keytool and jarsigner will install the provider dynamically (where ConfigFilePath is the path to the token configuration file). Here's an example of a command to list a PKCS#11 keystore when the Sun PKCS#11 provider has not been configured in the security properties file.

jarsigner -keystore NONE -storetype PKCS11 \
          -providerClass sun.security.pkcs11.SunPKCS11 \
          -providerArg /foo/bar/token.config \
          -list
-providerName providerName
If more than one provider has been configured in the java.security security properties file, you can use the -providerName option to target a specific provider instance. The argument to this option is the name of the provider.

For the Sun PKCS#11 provider, providerName is of the form SunPKCS11-TokenName, where TokenName is the name suffix that the provider instance has been configured with, as detailed in the configuration attributes table. For example, the following command lists the contents of the PKCS#11 keystore provider instance with name suffix SmartCard:

jarsigner -keystore NONE -storetype PKCS11 \
        -providerName SunPKCS11-SmartCard \
        -list
-Jjavaoption
Passes through the specified javaoption string directly to the Java interpreter. (jarsigner is actually a "wrapper" around the interpreter.) This option should not contain any spaces. It is useful for adjusting the execution environment or memory usage. For a list of possible interpreter options, type java -h or java -X at the command line.

-tsa url
If "-tsa http://example.tsa.url" appears on the command line when signing a JAR file then a timestamp is generated for the signature. The URL, http://example.tsa.url, identifies the location of the Time Stamping Authority (TSA). It overrides any URL found via the -tsacert option. The -tsa option does not require the TSA's public key certificate to be present in the keystore.

To generate the timestamp, jarsigner communicates with the TSA using the Time-Stamp Protocol (TSP) defined in RFC 3161. If successful, the timestamp token returned by the TSA is stored along with the signature in the signature block file.

-tsacert alias
If "-tsacert alias" appears on the command line when signing a JAR file then a timestamp is generated for the signature. The alias identifies the TSA's public key certificate in the keystore that is currently in effect. The entry's certificate is examined for a Subject Information Access extension that contains a URL identifying the location of the TSA.

The TSA's public key certificate must be present in the keystore when using -tsacert.

-altsigner class
Specifies that an alternative signing mechanism be used. The fully-qualified class name identifies a class file that extends the com.sun.jarsigner.ContentSigner abstract class. The path to this class file is defined by the -altsignerpath option. If the -altsigner option is used, jarsigner uses the signing mechanism provided by the specified class. Otherwise, jarsigner uses its default signing mechanism.

For example, to use the signing mechanism provided by a class named com.sun.sun.jarsigner.AuthSigner, use the jarsigner option "-altsigner com.sun.jarsigner.AuthSigner"

-altsignerpath classpathlist
Specifies the path to the class file (the class file name is specified with the -altsigner option described above) and any JAR files it depends on. If the class file is in a JAR file, then this specifies the path to that JAR file, as shown in the example below.

An absolute path or a path relative to the current directory may be specified. If classpathlist contains multiple paths or JAR files, they should be separated with a colon (:) on Solaris and a semi-colon (;) on Windows. This option is not necessary if the class is already in the search path.

Example of specifying the path to a jar file that contains the class file:

-altsignerpath /home/user/lib/authsigner.jar

Note that the JAR file name is included.

Example of specifying the path to the jar file that contains the class file:

-altsignerpath /home/user/classes/com/sun/tools/jarsigner/

Note that the JAR file name is omitted.

-strict
During the signing or verifying process, the command may issue warning messages. If you specify this option, the exit code of the tool reflects the severe warning messages that this command found. See ERRORS AND WARNINGS.
-verbose:sub-options
For the verifying process, the -verbose option takes sub-options to determine how much information will be shown. If -certs is also specified, the default mode (or sub-option all) displays each entry as it is being processed and following that, the certificate information for each signer of the JAR file. If -certs and the -verbose:grouped sub-option are specified, entries with the same signer info are grouped and displayed together along with their certificate information. If -certs and the -verbose:summary sub-option are specified, then entries with the same signer info are grouped and displayed together along with their certificate information but details about each entry are summarized and displayed as "one entry (and more)". See the examples section for more information.

ERRORS AND WARNINGS

During the signing or verifying process, the jarsigner command may issue various errors or warnings.

If there is a failure, the jarsigner command exits with code 1. If there is no failure, but there are one or more severe warnings, the jarsigner command exits with code 0 when the -strict option is not specified, or exits with the OR-value of the warning codes when the -strict is specified. If there is only informational warnings or no warning at all, the command always exits with code 0.

For example, if a certificate used to sign an entry is expired and has a KeyUsage extension that does not allow it to sign a file, the jarsigner command exits with code 12 (=4+8) when the -strict option is specified.

Note: Exit codes are reused because only the values from 0 to 255 are legal on Unix-based operating systems.

The following sections describes the names, codes, and descriptions of the errors and warnings that the jarsigner command can issue.

Failure

Reasons why the jarsigner command fails include (but are not limited to) a command line parsing error, the inability to find a keypair to sign the JAR file, or the verification of a signed JAR fails.

failure
Code 1. The signing or verifying fails.

Severe Warnings

Note: Severe warnings are reported as errors if you specify the -strict option.

Reasons why the jarsigner command issues a severe warning include the certificate used to sign the JAR file has an error or the signed JAR file has other problems.

hasExpiredCert
Code 4. This jar contains entries whose signer certificate has expired.
notYetValidCert
Code 4. This jar contains entries whose signer certificate is not yet valid.
chainNotValidated
Code 4. This jar contains entries whose certificate chain cannot be correctly validated.
badKeyUsage
Code 8. This JAR contains entries whose signer certificate's KeyUsage extension doesn't allow code signing.
badExtendedKeyUsage
Code 8. This jar contains entries whose signer certificate's ExtendedKeyUsage extension doesn't allow code signing.
badNetscapeCertType
Code 8. This jar contains entries whose signer certificate's NetscapeCertType extension doesn't allow code signing.
hasUnsignedEntry
Code 16. This jar contains unsigned entries which have not been integrity-checked.
notSignedByAlias
Code 32. This jar contains signed entries which are not signed by the specified alias(es).
aliasNotInStore
Code 32. This jar contains signed entries that are not signed by alias in this keystore.

Informational Warnings

Informational warnings include those that are not errors but regarded as bad practice. They do not have a code.

hasExpiringCert
This jar contains entries whose signer certificate will expire within six months.
noTimestamp
This jar contains signatures that does not include a timestamp. Without a timestamp, users may not be able to validate this JAR file after the signer certificate's expiration date (whose format is YYYY-MM-DD) or after any future revocation date.

EXAMPLES

Signing a JAR File

Suppose you have a JAR file named "bundle.jar" and you'd like to sign it using the private key of the user whose keystore alias is "jane" in the keystore named "mystore" in the "working" directory. You can use the following to sign the JAR file and name the signed JAR file "sbundle.jar":

    jarsigner -keystore /working/mystore -storepass <keystore password>
      -keypass <private key password> -signedjar sbundle.jar bundle.jar jane

Note that there is no -sigfile specified in the command above, so the generated .SF and .DSA files to be placed in the signed JAR file will have default names based on the alias name. That is, they will be named JANE.SF and JANE.DSA.

If you want to be prompted for the store password and the private key password, you could shorten the above command to

    jarsigner -keystore /working/mystore
      -signedjar sbundle.jar bundle.jar jane

If the keystore to be used is the default keystore (the one named ".keystore" in your home directory), you don't need to specify a keystore, as in:

    jarsigner -signedjar sbundle.jar bundle.jar jane

Finally, if you want the signed JAR file to simply overwrite the input JAR file (bundle.jar), you don't need to specify a -signedjar option:

    jarsigner bundle.jar jane

Verifying a Signed JAR File

To verify a signed JAR file, that is, to verify that the signature is valid and the JAR file has not been tampered with, use a command such as the following:

    jarsigner -verify sbundle.jar

If the verification is successful,

    jar verified.

is displayed. Otherwise, an error message appears.

You can get more information if you use the -verbose option. A sample use of jarsigner with the -verbose option is shown below, along with sample output:

    jarsigner -verify -verbose sbundle.jar

           198 Fri Sep 26 16:14:06 PDT 1997 META-INF/MANIFEST.MF
           199 Fri Sep 26 16:22:10 PDT 1997 META-INF/JANE.SF
          1013 Fri Sep 26 16:22:10 PDT 1997 META-INF/JANE.DSA
    smk   2752 Fri Sep 26 16:12:30 PDT 1997 AclEx.class
    smk    849 Fri Sep 26 16:12:46 PDT 1997 test.class

      s = signature was verified
      m = entry is listed in manifest
      k = at least one certificate was found in keystore

    jar verified.

Verification with Certificate Information

If you specify the -certs option when verifying, along with the -verify and -verbose options, the output includes certificate information for each signer of the JAR file, including the certificate type, the signer distinguished name information (if and only if it's an X.509 certificate), and, in parentheses, the keystore alias for the signer if the public key certificate in the JAR file matches that in a keystore entry. For example,

    jarsigner -keystore /working/mystore -verify -verbose -certs myTest.jar

           198 Fri Sep 26 16:14:06 PDT 1997 META-INF/MANIFEST.MF
           199 Fri Sep 26 16:22:10 PDT 1997 META-INF/JANE.SF
          1013 Fri Sep 26 16:22:10 PDT 1997 META-INF/JANE.DSA
           208 Fri Sep 26 16:23:30 PDT 1997 META-INF/JAVATEST.SF
          1087 Fri Sep 26 16:23:30 PDT 1997 META-INF/JAVATEST.DSA
    smk   2752 Fri Sep 26 16:12:30 PDT 1997 Tst.class

      X.509, CN=Test Group, OU=Java Software, O=Oracle, L=CUP, S=CA, C=US (javatest)
      X.509, CN=Jane Smith, OU=Java Software, O=Oracle, L=cup, S=ca, C=us (jane)

      s = signature was verified
      m = entry is listed in manifest
      k = at least one certificate was found in keystore

    jar verified.

If the certificate for a signer is not an X.509 certificate, there is no distinguished name information. In that case, just the certificate type and the alias are shown. For example, if the certificate is a PGP certificate, and the alias is "bob", you'd get

      PGP, (bob)

Verification of a JAR File that Includes Identity Database Signers

If a JAR file has been signed using the JDK 1.1 javakey tool, and thus the signer is an alias in an identity database, the verification output includes an "i" symbol. If the JAR file has been signed by both an alias in an identity database and an alias in a keystore, both "k" and "i" appear.

When the -certs option is used, any identity database aliases are shown in square brackets rather than the parentheses used for keystore aliases. For example:

    jarsigner -keystore /working/mystore -verify -verbose -certs writeFile.jar

           198 Fri Sep 26 16:14:06 PDT 1997 META-INF/MANIFEST.MF
           199 Fri Sep 26 16:22:10 PDT 1997 META-INF/JANE.SF
          1013 Fri Sep 26 16:22:10 PDT 1997 META-INF/JANE.DSA
           199 Fri Sep 27 12:22:30 PDT 1997 META-INF/DUKE.SF
          1013 Fri Sep 27 12:22:30 PDT 1997 META-INF/DUKE.DSA
   smki   2752 Fri Sep 26 16:12:30 PDT 1997 writeFile.html

      X.509, CN=Jane Smith, OU=Java Software, O=Oracle, L=cup, S=ca, C=us (jane)
      X.509, CN=Duke, OU=Java Software, O=Oracle, L=cup, S=ca, C=us [duke]

      s = signature was verified
      m = entry is listed in manifest
      k = at least one certificate was found in keystore
      i = at least one certificate was found in identity scope

    jar verified.

Note that the alias "duke" is in brackets to denote that it is an identity database alias, not a keystore alias.

Compatibility with JDK 1.1

The keytool and jarsigner tools completely replace the javakey tool provided in JDK 1.1. These new tools provide more features than javakey, including the ability to protect the keystore and private keys with passwords, and the ability to verify signatures in addition to generating them.

The new keystore architecture replaces the identity database that javakey created and managed. There is no backwards compatibility between the keystore format and the database format used by javakey in 1.1. However,

The following table explains how JAR files that were signed in JDK 1.1.x are treated in the Java platform.

JAR File Type Identity in 1.1 database Trusted Identity imported into Java Platform keystore from 1.1 database (4) Policy File grants privileges to Identity/Alias Privileges Granted

Signed JAR

NO

NO

NO

Default privileges granted to all code.

Unsigned JAR

NO

NO

NO

Default privileges granted to all code.

Signed JAR

NO

YES

NO

Default privileges granted to all code.

Signed JAR

YES/Untrusted

NO

NO

Default privileges granted to all code. (3)

Signed JAR

YES/Untrusted

NO

YES

Default privileges granted to all code. (1,3)

Signed JAR

NO

YES

YES

Default privileges granted to all code plus privileges granted in policy file.

Signed JAR

YES/Trusted

YES

YES

Default privileges granted to all code plus privileges granted in policy file. (2)

Signed JAR

YES/Trusted

NO

NO

All privileges

Signed JAR

YES/Trusted

YES

NO

All privileges (1)

Signed JAR

YES/Trusted

NO

YES

All privileges (1)

Notes:

  1. If an identity/alias is mentioned in the policy file, it must be imported into the keystore for the policy file to have any effect on privileges granted.
  2. The policy file/keystore combination has precedence over a trusted identity in the identity database.
  3. Untrusted identities are ignored in the Java platform.
  4. Only trusted identities can be imported into JDK keystores.

SEE ALSO


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