The RMD160 functions implement the 160-bit RIPE message digest hash algorithm (RMD-160). RMD-160 is used to generate a condensed representation of a message called a message digest. The algorithm takes a message less than 2^64 bits as input and produces a 160-bit digest suitable for use as a digital signature.
The RMD160 functions are considered to be more secure than the
md4(3) and
md5(3) functions and at least as secure as the
sha1(3) function. All share a similar interface.
The
RMD160Init() function initializes a RMD160_CTX
context for use with
RMD160Update(), and
RMD160Final(). The
RMD160Update() function adds
data of length
nbytes to the RMD160_CTX specified by
context.
RMD160Final() is called when all data has been added via
RMD160Update() and stores a message digest in the
digest parameter. When a null pointer is passed to
RMD160Final() as first argument only the final padding will be applied and the current context can still be used with
RMD160Update().
The
RMD160Transform() function is used by
RMD160Update() to hash 512-bit blocks and forms the core of the algorithm. Most programs should use the interface provided by
RMD160Init(),
RMD160Update() and
RMD160Final() instead of calling
RMD160Transform() directly.
The
RMD160End() function is a front end for
RMD160Final() which converts the digest into an ASCII representation of the 160 bit digest in hexadecimal.
The
RMD160File() function calculates the digest for a file and returns the result via
RMD160End(). If
RMD160File() is unable to open the file a NULL pointer is returned.
The
RMD160Data() function calculates the digest of an arbitrary string and returns the result via
RMD160End().
For each of the
RMD160End(),
RMD160File(), and
RMD160Data() functions the
buf parameter should either be a string of at least 41 characters in size or a NULL pointer. In the latter case, space will be dynamically allocated via
malloc(3) and should be freed using
free(3) when it is no longer needed.