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author | Ralf S. Engelschall <rse@openssl.org> | 1998-12-21 10:52:47 +0000 |
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committer | Ralf S. Engelschall <rse@openssl.org> | 1998-12-21 10:52:47 +0000 |
commit | d02b48c63a58ea4367a0e905979f140b7d090f86 (patch) | |
tree | 504f62ed3d84799f785b9cd9fab255a21b0e1b0e /doc/sha.doc | |
download | openssl-d02b48c63a58ea4367a0e905979f140b7d090f86.tar.gz |
Import of old SSLeay release: SSLeay 0.8.1b
Diffstat (limited to 'doc/sha.doc')
-rw-r--r-- | doc/sha.doc | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/doc/sha.doc b/doc/sha.doc new file mode 100644 index 0000000000..895fa182ed --- /dev/null +++ b/doc/sha.doc @@ -0,0 +1,52 @@ +The SHA (Secure Hash Algorithm) library. +SHA is a message digest algorithm that can be used to condense an arbitrary +length message down to a 20 byte hash. The functions all need to be passed +a SHA_CTX which is used to hold the SHA context during multiple SHA_Update() +function calls. The normal method of use for this library is as follows +This library contains both SHA and SHA-1 digest algorithms. SHA-1 is +an update to SHA (which should really be called SHA-0 now) which +tweaks the algorithm slightly. The SHA-1 algorithm is used by simply +using SHA1_Init(), SHA1_Update(), SHA1_Final() and SHA1() instead of the +SHA*() calls + +SHA_Init(...); +SHA_Update(...); +... +SHA_Update(...); +SHA_Final(...); + +This library requires the inclusion of 'sha.h'. + +The functions are as follows: + +void SHA_Init( +SHA_CTX *c); + This function needs to be called to initiate a SHA_CTX structure for + use. + +void SHA_Update( +SHA_CTX *c; +unsigned char *data; +unsigned long len); + This updates the message digest context being generated with 'len' + bytes from the 'data' pointer. The number of bytes can be any + length. + +void SHA_Final( +unsigned char *md; +SHA_CTX *c; + This function is called when a message digest of the data digested + with SHA_Update() is wanted. The message digest is put in the 'md' + array and is SHA_DIGEST_LENGTH (20) bytes long. + +unsigned char *SHA( +unsigned char *d; +unsigned long n; +unsigned char *md; + This function performs a SHA_Init(), followed by a SHA_Update() + followed by a SHA_Final() (using a local SHA_CTX). + The resulting digest is put into 'md' if it is not NULL. + Regardless of the value of 'md', the message + digest is returned from the function. If 'md' was NULL, the message + digest returned is being stored in a static structure. + |