CryptoXpress CF supports multiple message digest algorithms including MD5 and SHA1.
A message digest (also sometimes referred to as a one-way hash function) is a fixed length computationally unique identifier corresponding to a set of data. The result of the algorithm is that each file or data string digested will map to a particular block of information called a message digest. The digest is not random; digesting the same unit of data with the same algorithm will always produce the same message digest.
Most users prefer to use the MD5 message digest algorithm. MD5 belongs to a family of one-way hash functions called message digest algorithms. The MD5 system is defined in RFC 1321. MD5 takes a message of arbitrary length and produces as output a 128-bit message digest. It is conjectured that it is computationally infeasible to produce two different messages having the same message digest, or to produce any message having a given message digest.
RFC 1321 also defines a certification suite to validate correct implementation of the algorithm. CryptoXpress LT is validated against this suite.
Message digests have many uses. In particular they are used to authenticate data. For example, to create a digest for authentication, data can be digested and the digest saved. Later, to validate that the data has not been altered, the data is digested again and the result is compare against the original digest. If they differ, the data has been altered. This is very different from encryption because the actual data is not modified when it is digested. Encryption is intended to protect the confidentiality of data.