NAME
SHA1, SHA1_Init,
SHA1_Update, SHA1_Final,
SHA224, SHA224_Init,
SHA224_Update, SHA224_Final,
SHA256, SHA256_Init,
SHA256_Update, SHA256_Final,
SHA384, SHA384_Init,
SHA384_Update, SHA384_Final,
SHA512, SHA512_Init,
SHA512_Update, SHA512_Final
— Secure Hash
Algorithm
SYNOPSIS
#include
<openssl/sha.h>
unsigned char *
SHA1(const unsigned char *d,
size_t n, unsigned char
*md);
int
SHA1_Init(SHA_CTX *c);
int
SHA1_Update(SHA_CTX *c,
const void *data, size_t
len);
int
SHA1_Final(unsigned char *md,
SHA_CTX *c);
unsigned char *
SHA224(const unsigned char *d,
size_t n, unsigned char
*md);
int
SHA224_Init(SHA256_CTX *c);
int
SHA224_Update(SHA256_CTX *c,
const void *data, size_t
len);
int
SHA224_Final(unsigned char *md,
SHA256_CTX *c);
unsigned char *
SHA256(const unsigned char *d,
size_t n, unsigned char
*md);
int
SHA256_Init(SHA256_CTX *c);
int
SHA256_Update(SHA256_CTX *c,
const void *data, size_t
len);
int
SHA256_Final(unsigned char *md,
SHA256_CTX *c);
unsigned char *
SHA384(const unsigned char *d,
size_t n, unsigned char
*md);
int
SHA384_Init(SHA512_CTX *c);
int
SHA384_Update(SHA512_CTX *c,
const void *data, size_t
len);
int
SHA384_Final(unsigned char *md,
SHA512_CTX *c);
unsigned char *
SHA512(const unsigned char *d,
size_t n, unsigned char
*md);
int
SHA512_Init(SHA512_CTX *c);
int
SHA512_Update(SHA512_CTX *c,
const void *data, size_t
len);
int
SHA512_Final(unsigned char *md,
SHA512_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, which is not thread safe.
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.
The SHA224, SHA256, SHA384, and SHA512 families of functions
operate in the same way as the SHA1 functions. Note that SHA224 and SHA256
use a SHA256_CTX object instead of
SHA_CTX, and SHA384 and SHA512 use
SHA512_CTX. The buffer md must
have space for the output from the SHA variant being used:
SHA224_DIGEST_LENGTH,
SHA256_DIGEST_LENGTH,
SHA384_DIGEST_LENGTH, or
SHA512_DIGEST_LENGTH bytes.
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(), SHA224(),
SHA256(), SHA384(), and
SHA512() return a pointer to the hash value. The
other functions return 1 for success or 0 otherwise.
SEE ALSO
STANDARDS
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
HISTORY
SHA1(),
SHA1_Init(), SHA1_Update(),
and SHA1_Final() first appeared in SSLeay 0.5.1 and
have been available since OpenBSD 2.4.
The other functions first appeared in OpenSSL 0.9.8 and have been available since OpenBSD 4.5.