The digital signature generate and digital signature verify callable services support several methods for formatting a hash, and in some cases a descriptor for the hashing method, into a bit-string to be processed by the cryptographic algorithm. This topic discusses the ANSI X9.31 and PKCS #1 methods. The ISO 9796-1 method can be found in the ISO standard.

This topic also describes the PKCS #1, version 1, 1.5, and 2.0, methods for placing a key in a bit string for RSA ciphering in a key exchange.