MD2
More info
- Creator
- Ron Rivest
- Released
- 1989
- Type
- Cryptographic hash function
- Spec
- RFC 1319
Ron Rivest's first hash in the MD family, built for 8-bit processors and every bit as slow as that suggests.
MD2 produces a 128-bit digest and works byte by byte, using a substitution table derived from the digits of pi. It was aimed at smart cards and small processors, and was quickly followed by MD4 and MD5, which ran far faster on 32-bit hardware.
Even so, MD2 lingered in PKI: several 1990s root certificates were signed with md2WithRSAEncryption and stayed in browser trust stores long after anyone wrote new code for the algorithm. Preimage attacks appeared in 2004 and improved in 2008, and in 2011 RFC 6149 formally moved MD2 to Historic status — the IETF's standardised way of saying rest in peace.