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The MD5 module allows you to use the RSA Data Security Inc. MD5 Message
Digest algorithm from within Perl programs.
A new MD5 context object is created with the new operation. Multiple
simultaneous digest contexts can be maintained, if desired. The context is
updated with the add operation which adds the strings contained in the LIST
parameter. Note, however, that add('foo', 'bar'), add('foo') followed by
add('bar') and add('foobar') should all give the same result.
The final message digest value is returned by the digest operation as a
16-byte binary string. This operation delivers the result of add operations
since the last new or reset operation. Note that the digest operation is
effectively a destructive, read-once operation. Once it has been performed, the
context must be reset before being used to calculate another digest value.
Several convenience functions are also provided. The addfile operation
takes an open file-handle and reads it until end-of file in 1024 byte blocks
adding the contents to the context. The file-handle can either be specified by
name or passed as a type-glob reference. The hexdigest operation calls digest
and returns the result as a printable string of hexdecimal digits.
The hash operation can act as either a static member function (you
invoke it on the MD5 class) or as a normal virtual function. In both cases it
performs the complete MD5 cycle (reset, add, digest) on the supplied scalar
value. This is convenient for handling small quantities of data. When invoked on
the class a temporary context is created. When invoked through an already
created context object, this context is used. The latter form is slightly more
efficient. The hexhash operation is analogous to hexdigest.
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