mac

- calculate message authentication codes of the input

Synopsis

/usr/bin/mac -l | [-v] -a algorithm [-k keyfile] [file]...

Description

The mac utility calculates the message authentication code (MAC) of the given file or files or stdin using the algorithm specified.

If more than one file is given, each line of output is the MAC of a single file.

Options

The following options are supported:

-a algorithm

Specifies the name of the algorithm to use during the encryption or decryption process. See USAGE, Algorithms for details. Note: Algorithms for producing general length MACs are not supported.

-k keyfile

Specifies the file containing the key value for the encryption algorithm. Each algorithm has specific key material requirements, as stated in the PKCS#11 specification. If -k is not specified, mac prompts for key material using getpassphrase(3C).

For information on generating a key file, see dd(1M) or System Administration Guide: Security Services.

-l

Displays the list of algorithms available on the system. This list can change depending on the configuration of the cryptographic framework. The keysizes are displayed in bits.

-v

Provides verbose information.

Usage

Algorithms

The supported algorithms are displayed with the -l option. These algorithms are provided by the cryptographic framework. Each supported algorithm is an alias to the most commonly used and least restricted version of a particular algorithm type. For example, md5_hmac is an alias to CKM_MD5_HMAC.

These aliases are used with the -a option and are case-sensitive.

Passphrase

When the -k option is not used during encryption and decryption tasks, the user is prompted for a passphrase. The passphrase is manipulated into a more secure key using the PBKDF2 algorithm specified in PKCS #5.

Examples

Example 1 Listing Available Algorithms

The following example lists available algorithms:

example$ mac -l
Algorithm       Keysize:  Min   Max
-----------------------------------
des_mac                    64    64
sha1_hmac                   8   512
md5_hmac                    8   512
sha256_hmac                 8   512
sha384_hmac                 8  1024
sha512_hmac                 8  1024

Example 2 Getting the Message Authentication Code

The following example gets the message authentication code for a file:

example$ mac -v -k mykey -a sha1_hmac /export/foo
sha1_hmac (/export/foo) = 913ced311df10f1708d9848641ca8992f4718057

Exit Status

The following exit values are returned:

0

Successful completion.

>0

An error occurred.

Attributes

See attributes(5) for descriptions of the following attributes:

See Also

digest(1), dd(1M), getpassphrase(3C), libpkcs11(3LIB), attributes(5), pkcs11_softtoken(5)

System Administration Guide: Security Services

RSA PKCS#11 v2.20 and RSA PKCS#5 v2.0, http://www.rsasecurity.com