ISO/IEC 9796-2:2010 specifies three digital signature schemes giving message recovery, two of which are deterministic (non-randomized) and one of which is randomized. The security of all three schemes is based on the difficulty of factorizing large numbers. All three schemes can provide either total or partial message recovery.
ISO/IEC 9796-2:2010 specifies the method for key production for the three signature schemes. However, techniques for key management and for random number generation (as required for the randomized signature scheme), are outside the scope of ISO/IEC 9796-2:2010.
The first mechanism specified in ISO/IEC 9796-2:2010 is only applicable for existing implementations, and is retained for reasons of backward compatibility.