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HP-UX MD5 Secure Checksum

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Product details and specifications

The HP-UX MD5 Secure Checksum A.01.01.02 bundle (bundle name MD5Checksum) provides a file integrity utility and API based on the standard Message Digest 5 (MD5) algorithm. The MD5Checksum bundle consists of the following two components that can be installed independently:

  • HP-UX MD5sum (md5sum checksum command)
  • HP-UX LibCryptX (libcryptx libraries providing MD5 APIs)

The md5sum command is a more secure alternative to the cksum command. The cksum command is a file integrity utility currently available on HP-UX that is based on a weak cyclic redundancy check mechanism (32-bit wide), and is prone to high collision rates.

The md5sum command is based on the MD5 algorithm and generates 128-bit message digests. The md5sum command enables you to verify the integrity of files downloaded over a network connection. You can also use the md5sum command to compare files and verify the integrity of files.

The HP-UX MD5sum product uses the MD5-based APIs in the the HP-UX LibCryptX product.

In addition to the md5sum command, the HP-UX MD5sum product includes the md5sum (1) man page, and a message catalog file.

The HP-UX LibCryptX product includes architecture-specific versions of the libcryptx shared library (used by the md5sum command), include file, and the md5(3) manpage.

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Key Features and Benefits

The following are the list of key features supported by the HP-UX MD5 Secure Checksum bundle:

  • Strong file integrity check command (md5sum)

The HP-UX MD5sum product provides a user utility that generates MD5 message digests for files. The 128-bit fingerprint output of the MD5 hash is platform independent and conforms to RFC 1321 (The MD5 Message-Digest Algorithm). This product works with regular files (text, binary objects), directories and standard input.

  • New library (libcryptx)

The new shared library containing the MD5 interfaces is called libcryptx. The md5sum command uses the libcryptx library for the MD5 routines. The MD5 APIs provide methods for hashing files and finite byte streams.

  • Support for large files

The md5sum command and APIs support hashing of large files up to 260 bytes in size.

  • High performance and multi-threading capability

The md5sum command provides the -n option to hash input file arguments in parallel (see md5sum (1)), significantly increasing the overall command performance. This performance improvement is based on a patented* architecture.

  • Scalability and adaptability

The multi-threading feature of md5sum scales with the number of CPUs and adapts to the host system.

  • Linux md5sum and HP-UX md5sum compatibility

The default output of the md5sum command is compatible with the default output open source versions of md5sum, as described in the GNU textutils package, available at By default, the md5sum command prints an MD5 hash and a file name for each input argument to the command. Note that the HP-UX MD5 Secure Checksum does not support some open source options, such as the -c and -h options.

The -k option generates a three-column (hash, file size, and file name) output that is compatible with the existing cksum command output format.'

Related Documentation

For more information about the HP-UX MD5 Secure Checksum bundle, see the following documentation:

  • Man pages
    • The md5(3) man page
    • The md5sum(1) man page

    HP-UX MD5 Secure Checksum Release Notes (available at, under "Security Products and Features").

* Patent pending.

Additional product information
Product #: md5checksum
Version: A.01.01.02
Software specification: HP-UX 11i v1 (MD5Checksum_A.01.01.02_HP-UX_B.11.11_32+64.depot)
HP-UX 11i v2 (MD5Checksum_A.01.01.02_HP-UX_B.11.23_IA+PA.depot)
HP-UX 11i v3 (MD5Checksum_A.01.01.02_HP-UX_B.11.31_IA+PA.depot )