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"THE BEER-WARE LICENSE" (Revision 42):
<phk@FreeBSD.org> wrote this file. As long as you retain this notice you
can do whatever you want with this stuff. If we meet some day, and you think
this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
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From: Id: mdX.3,v 1.14 1999/02/11 20:31:49 wollman Exp
$FreeBSD: releng/10.3/lib/libmd/ripemd.3 263955 2014-03-31 00:28:54Z gjb $
.Dd March 28, 2014 .Dt RIPEMD 3 .Os .Sh NAME .Nm RIPEMD160_Init , .Nm RIPEMD160_Update , .Nm RIPEMD160_Final , .Nm RIPEMD160_End , .Nm RIPEMD160_File , .Nm RIPEMD160_FileChunk , .Nm RIPEMD160_Data .Nd calculate the RIPEMD160 message digest .Sh LIBRARY .Lb libmd .Sh SYNOPSIS n sys/types.h n ripemd.h .Ft void .Fn RIPEMD160_Init "RIPEMD160_CTX *context" .Ft void .Fn RIPEMD160_Update "RIPEMD160_CTX *context" "const unsigned char *data" "unsigned int len" .Ft void .Fn RIPEMD160_Final "unsigned char digest[20]" "RIPEMD160_CTX *context" .Ft "char *" .Fn RIPEMD160_End "RIPEMD160_CTX *context" "char *buf" .Ft "char *" .Fn RIPEMD160_File "const char *filename" "char *buf" .Ft "char *" .Fn RIPEMD160_FileChunk "const char *filename" "char *buf" "off_t offset" "off_t length" .Ft "char *" .Fn RIPEMD160_Data "const unsigned char *data" "unsigned int len" "char *buf" .Sh DESCRIPTION The .Li RIPEMD160_ 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 .Dq fingerprint of the input-data, which does not disclose the actual input.
p The .Fn RIPEMD160_Init , .Fn RIPEMD160_Update , and .Fn RIPEMD160_Final functions are the core functions. Allocate an .Vt RIPEMD160_CTX , initialize it with .Fn RIPEMD160_Init , run over the data with .Fn RIPEMD160_Update , and finally extract the result using .Fn RIPEMD160_Final .
p The .Fn RIPEMD160_End function is a wrapper for .Fn RIPEMD160_Final which converts the return value to a 41-character (including the terminating '\e0') .Tn ASCII string which represents the 160 bits in hexadecimal.
p The .Fn RIPEMD160_File function calculates the digest of a file, and uses .Fn RIPEMD160_End to return the result. If the file cannot be opened, a null pointer is returned. The .Fn RIPEMD160_FileChunk function is similar to .Fn RIPEMD160_File , but it only calculates the digest over a byte-range of the file specified, starting at .Fa offset and spanning .Fa length bytes. If the .Fa length parameter is specified as 0, or more than the length of the remaining part of the file, .Fn RIPEMD160_FileChunk calculates the digest from .Fa offset to the end of file. The .Fn RIPEMD160_Data function calculates the digest of a chunk of data in memory, and uses .Fn RIPEMD160_End to return the result.
p When using .Fn RIPEMD160_End , .Fn RIPEMD160_File , or .Fn RIPEMD160_Data , the .Fa buf argument can be a null pointer, in which case the returned string is allocated with .Xr malloc 3 and subsequently must be explicitly deallocated using .Xr free 3 after use. If the .Fa buf argument is non-null it must point to at least 41 characters of buffer space. .Sh SEE ALSO .Xr md4 3 , .Xr md5 3 , .Xr sha 3 .Sh HISTORY These functions appeared in .Fx 4.0 . .Sh AUTHORS The core hash routines were implemented by Eric Young based on the published .Tn RIPEMD160 specification. .Sh 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.