NAME

SYNOPSIS

void
RMD160Init(RMD160_CTX *context);

void
RMD160Update(RMD160_CTX *context, const u_int8_t *data, size_t nbytes);

void
RMD160Pad(RMD160_CTX *context);

void
RMD160Final(u_int8_t digest[RMD160_DIGEST_LENGTH], RMD160_CTX *context);

void
RMD160Transform(u_int32_t state[5], const u_int8_t block[RMD160_BLOCK_LENGTH]);

char *
RMD160End(RMD160_CTX *context, char *buf);

char *
RMD160File(const char *filename, char *buf);

char *
RMD160FileChunk(const char *filename, char *buf, off_t offset, off_t length);

char *
RMD160Data(const u_int8_t *data, size_t len, char *buf);

DESCRIPTION

The RMD160 functions are considered to be more secure than the 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.

The RMD160Pad() function can be used to apply padding to the message digest as in RMD160Final(), but 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.

RMD160FileChunk() behaves like RMD160File() but calculates the digest only for that portion of the file starting at offset and continuing for length bytes or until end of file is reached, whichever comes first. A zero length can be specified to read until end of file. A negative length or offset will be ignored.

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.

EXAMPLES

RMD160_CTX rmd;
u_int8_t results[RMD160_DIGEST_LENGTH];
char *buf;
int n;

buf = "abc";
n = strlen(buf);
RMD160Init(&rmd);
RMD160Update(&rmd, (u_int8_t *)buf, n);
RMD160Final(results, &rmd);

/* Print the digest as one long hex value */
printf("0x");
for (n = 0; n < RMD160_DIGEST_LENGTH; n++)
	printf("%02x", results[n]);
putchar('\n');

Alternately, the helper functions could be used in the following way:

RMD160_CTX rmd;
u_int8_t output[RMD160_DIGEST_STRING_LENGTH];
char *buf = "abc";

printf("0x%s\n", RMD160Data(buf, strlen(buf), output));

SEE ALSO

H. Dobbertin, A. Bosselaers, B. Preneel, RIPEMD-160, a strengthened version of RIPEMD.

Information technology - Security techniques - Hash-functions - Part 3: Dedicated hash-functions, ISO/IEC 10118-3.

H. Dobbertin, A. Bosselaers, B. Preneel, The RIPEMD-160 cryptographic hash function, Dr. Dobb's Journal, Vol. 22, No. 1, pp. 24-28, January 1997.

HISTORY

AUTHORS

The RMD160End(), RMD160File(), RMD160FileChunk(), and RMD160Data() helper functions are derived from code written by Poul-Henning Kamp.