The [Tcllib] '''[http://core.tcl.tk/tcllib/doc/trunk/embedded/www/tcllib/files/modules/md5/md5.html%|%md5]''' module creates [MD5] message digests .



** Documentation **

   [http://tcllib.sourceforge.net/doc/md5.html%|%official reference] ([http://docs.activestate.com/activetcl/8.6/tcllib/md5/md5.html%|%alternate]) :   

   [http://core.tcl.tk/tcllib/doc/trunk/embedded/www/tcllib/files/modules/md5/md5.html%|%official reference] , development version :   



** Description **

The [tcllib] implementation of MD5 will defer to the md5 from the [Trf] package
if that is available.

[DKF] : The version in [Tcllib] is partially built on [MD5Pure] .



** Hexadecimal Representation **  

[jmn] 2004-02-01 :  Are there some gotchas the novice user should be aware of here? 
What happens when you use the binary value returned by `md5::md5` as part of a string, as in the following snippet taken from [Tuplespace]

======
proc tid {tuple} {
    return "\#Tuple[::md5::md5 $tuple]"
}
======

See my comments about half way down that page. Basically it looks like `md5::md5` of the string `hello there test etc` returns a value that includes a carriage return. As I guess can be seen by the existence of `0D` when you look at the hex result: 

======
% md5 -hex {hello there test etc}
FC7EB2BA07710DECECC688BCEA5BB323
======

I assume there may be other characters that may cause problems when using the binary result in a string - so presumably one should always use the -hex option for this sort of situation(?)

When and how does one use the binary result then?

[PT] : You have turned the binary result into the string representation of a binary result there. If
you want a string then you should use ''-hex'' or in some other way arrange to protect the data.
For instance, once a string function is used any embedded nil chars are going to terminate the data.
The binary form is required if you are putting the result into a binary format -- for instance a network
protocol or embedded into a file format.



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