NAME
RIPEMD160_Init,
RIPEMD160_Update,
RIPEMD160_Final,
RIPEMD160_End,
RIPEMD160_File,
RIPEMD160_FileChunk,
RIPEMD160_Data —
calculate the RIPEMD160 message
digest
LIBRARY
library “libmd”
SYNOPSIS
#include
<sys/types.h>
#include <ripemd.h>
void
RIPEMD160_Init(RIPEMD160_CTX
*context);
void
RIPEMD160_Update(RIPEMD160_CTX
*context, const unsigned
char *data, unsigned int
len);
void
RIPEMD160_Final(unsigned
char digest[20],
RIPEMD160_CTX
*context);
char *
RIPEMD160_End(RIPEMD160_CTX
*context, char
*buf);
char *
RIPEMD160_File(const
char *filename, char
*buf);
char *
RIPEMD160_FileChunk(const
char *filename, char
*buf, off_t offset,
off_t length);
char *
RIPEMD160_Data(const
unsigned char *data,
unsigned int len,
char *buf);
DESCRIPTION
TheRIPEMD160_ functions calculate a 160-bit
cryptographic checksum (digest) for any number of input bytes. A cryptographic
checksum is a one-way hash function; that is, it is computationally
impractical to find the input corresponding to a particular output. This net
result is a “fingerprint” of the input-data, which does not
disclose the actual input.
The
RIPEMD160_Init(),
RIPEMD160_Update(),
and RIPEMD160_Final() functions are the core
functions. Allocate an RIPEMD160_CTX, initialize it
with RIPEMD160_Init(), run over the data with
RIPEMD160_Update(), and finally extract the result
using RIPEMD160_Final(), which will also erase the
RIPEMD160_CTX.
The
RIPEMD160_End()
function is a wrapper for
RIPEMD160_Final()
which converts the return value to a 41-character (including the terminating
'\0') ASCII string which represents the 160 bits in hexadecimal.
The
RIPEMD160_File()
function calculates the digest of a file, and uses
RIPEMD160_End() to return the result. If the file
cannot be opened, a null pointer is returned. The
RIPEMD160_FileChunk()
function is similar to RIPEMD160_File(), but it only
calculates the digest over a byte-range of the file specified, starting at
offset and spanning length
bytes. If the length parameter is specified as 0, or
more than the length of the remaining part of the file,
RIPEMD160_FileChunk() calculates the digest from
offset to the end of file. The
RIPEMD160_Data() function calculates the digest of a
chunk of data in memory, and uses RIPEMD160_End() to
return the result.
When using
RIPEMD160_End(),
RIPEMD160_File(), or
RIPEMD160_Data(),
the buf argument can be a null pointer, in which case
the returned string is allocated with
malloc(3) and subsequently must be explicitly deallocated using
free(3) after use. If the buf argument is
non-null it must point to at least 41 characters of buffer space.
SEE ALSO
HISTORY
These functions appeared in FreeBSD 4.0.
AUTHORS
The core hash routines were implemented by Eric Young based on the published RIPEMD160 specification.
BUGS
No method is known to exist which finds two files having the same hash value, nor to find a file with a specific hash value. There is on the other hand no guarantee that such a method does not exist.