Personal tools
Skip to content. | Skip to navigation
The Digest:: modules calculate digests, also called "fingerprints" or "hashes", of some data, called a message. The digest is (usually) some small/fixed size string. The actual size of the digest depend of the algorithm used. The message is simply a sequence of arbitrary bytes or bits.
The Digest:: modules calculate digests, also called "fingerprints" or "hashes", of some data, called a message. The digest is (usually) some small/fixed size string. The actual size of the digest depends of the algorithm used. The message is simply a sequence of arbitrary bytes or bits.
Digest::BubbleBabble takes a message digest (generated by either of the MD5 or SHA-1 message digest algorithms) and creates a fingerprint of that digest in "bubble babble" format. Bubble babble is a method of representing a message digest as a string of "real" words, to make the fingerprint easier to remember. The "words" are not necessarily real words, but they look more like words than a string of hex characters. Bubble babble fingerprinting is used by the SSH2 suite (and, consequently, by Net::SSH::Perl, the Perl SSH implementation) to display easy-to-remember key fingerprints. The key (a DSA or RSA key) is converted into a textual form, digested using Digest::SHA1, and run through bubblebabble to create the key fingerprint.
The Digest::CRC module calculates CRC sums of all sorts. It contains wrapper functions with the correct parameters for CRC-CCITT, CRC-16 and CRC-32.
HMAC is used for message integrity checks between two parties that share a secret key, and works in combination with some other Digest algorithm, usually MD5 or SHA-1. The HMAC mechanism is described in RFC 2104. HMAC follow the common Digest:: interface, but the constructor takes the secret key and the name of some other simple Digest:: as argument.