Template::Plugin::Digest::MD5 - TT2 interface to the MD5 Algorithm
[% USE Digest.MD5 -%] [% checksum = content FILTER md5 -%] [% checksum = content FILTER md5_hex -%] [% checksum = content FILTER md5_base64 -%] [% checksum = content.md5 -%] [% checksum = content.md5_hex -%] [% checksum = content.md5_base64 -%]
The Digest.MD5 Template Toolkit plugin provides access to the MD5 algorithm via the
Digest::MD5 module. It is used like a plugin but installs filters and vmethods into the current context.
When you invoke
[% USE Digest.MD5 %]
the following filters (and vmethods of the same name) are installed into the current context:
Calculate the MD5 digest of the input, and return it in binary form. The returned string will be 16 bytes long.
md5, but will return the digest in hexadecimal form. The length of the returned string will be 32 and it will only contain characters from this set: '0'..'9' and 'a'..'f'.
md5, but will return the digest as a base64 encoded string. The length of the returned string will be 22 and it will only contain characters from this set: 'A'..'Z', 'a'..'z', '0'..'9', '+' and '/'.
Note that the base64 encoded string returned is not padded to be a multiple of 4 bytes long. If you want interoperability with other base64 encoded md5 digests you might want to append the redundant string "==" to the result.
As the filters are also available as vmethods the following are all equivalent:
FILTER md5_hex; content; END; content FILTER md5_hex; content.md5_base64;
The Digest::MD5 man page notes that the MD5 algorithm is not as strong as it used to be. It has since 2005 been easy to generate different messages that produce the same MD5 digest. It still seems hard to generate messages that produce a given digest, but it is probably wise to move to stronger algorithms for applications that depend on the digest to uniquely identify a message.
Andrew Ford <A.Ford@ford-mason.co.uk>
Thanks to Darren Chamberlain for a patch for vmethod support.
Copyright (C) 2006 Andrew Ford. All Rights Reserved.