# Is the first version of the Message-Digest algorithm by Ronald Rivest publically available?

Diving into the history and evolution of the Message-Digest algorithm by Ronald Rivest, I have been able to track back papers from MD6 down to MD2. Yet, somehow I can not seem to be able to find any papers, specifications or even the slightest indications of MD1.

As the numbering (MD2, MD4, MD5, MD6) seems to be a constant, it would be logic to expect that MD1 did exist at some point in the past. Since I can not find anything related, I'm reaching out for help...

Has MD1 ever been published or was MD2 indeed the first Message-Digest algorithm that Ronald Rivest showed to the world? And if MD1 has been published, where can I find that publication (or a copy of it)?

• The talk page on Wikipedia has some information, if you haven't seen it: en.wikipedia.org/wiki/Talk%3AMD4. It suggests MD1 as such never existed, but was instead just MD (and was never published) and that MD3 was a failed experiment; apparently there exists a specification somewhere (I cannot find the referenced document 1335: MD2, MD4, MD5, SHA and other hash functions. M.J.B. Robshaw). The best way to know would be to send the author an email, though :p Aug 31 '13 at 10:54