NAME¶
SHA1, SHA1_Init, SHA1_Update, SHA1_Final - Secure Hash Algorithm
SYNOPSIS¶
#include <openssl/sha.h>
unsigned char *SHA1(const unsigned char *d, unsigned long n,
unsigned char *md);
int SHA1_Init(SHA_CTX *c);
int SHA1_Update(SHA_CTX *c, const void *data,
unsigned long len);
int SHA1_Final(unsigned char *md, SHA_CTX *c);
DESCRIPTION¶
SHA-1 (Secure Hash Algorithm) is a cryptographic hash function with a 160 bit
output.
SHA1() computes the SHA-1 message digest of the
n bytes at
d and places it in
md (which must have space for
SHA_DIGEST_LENGTH == 20 bytes of output). If
md is NULL, the digest is
placed in a static array.
The following functions may be used if the message is not completely stored in
memory:
SHA1_Init() initializes a
SHA_CTX structure.
SHA1_Update() can be called repeatedly with chunks of the message to be
hashed (
len bytes at
data).
SHA1_Final() places the message digest in
md, which must have
space for SHA_DIGEST_LENGTH == 20 bytes of output, and erases the
SHA_CTX.
Applications should use the higher level functions
EVP_DigestInit(3) etc.
instead of calling the hash functions directly.
The predecessor of SHA-1, SHA, is also implemented, but it should be used only
when backward compatibility is required.
RETURN VALUES¶
SHA1() returns a pointer to the hash value.
SHA1_Init(),
SHA1_Update() and
SHA1_Final() return 1 for
success, 0 otherwise.
SHA: US Federal Information Processing Standard FIPS PUB 180 (Secure Hash
Standard), SHA-1: US Federal Information Processing Standard FIPS PUB 180-1
(Secure Hash Standard), ANSI X9.30
SEE ALSO¶
ripemd(3),
hmac(3),
EVP_DigestInit(3)
HISTORY¶
SHA1(),
SHA1_Init(),
SHA1_Update() and
SHA1_Final()
are available in all versions of SSLeay and OpenSSL.