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::sha, and run through bubblebabble to create the key fingerprint.