1. RSA Reference Implementation. This was a fairly open implementation of the RSA algorithm that has been embedded into many problems. This is not the source code that RSA sells to vendors, but an open-source version that has been imbedded within freeware/open-source products (like ssh). A patent-license is still required when using this code in commercial products, though. Key point: RSAREF has been supported by RSA (the company) for a long time, and a number of security holes have been found in this implementation. RSA wants people to use the BSAFE development kit instead. In late 1999 in particular, a bug was found that allows ssh to be hacked. From Hacking-Lexicon