SHA256 (3)
Leading comments
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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 AlgorithmSYNOPSIS
#include <openssl/sha.h>
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 *SHA1(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 *SHA224(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 *SHA256(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 *SHA384(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);
unsigned char *SHA512(const unsigned char *d, size_t n,
unsigned char *md);
DESCRIPTION
Applications should use the higher level functions EVP_DigestInit(3) etc. instead of calling the hash functions directly.
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. Note: setting md to NULL
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 for the SHA1
functions. Note that SHA224
and SHA256
use a
SHA256_CTX
object instead of SHA_CTX
. SHA384
and SHA512
use SHA512_CTX
.
The buffer md must have space for the output from the SHA
variant being used
(defined by SHA224_DIGEST_LENGTH, SHA256_DIGEST_LENGTH, SHA384_DIGEST_LENGTH
and
SHA512_DIGEST_LENGTH
). Also note that, as for the SHA1
() function above, the
SHA224
(), SHA256
(), SHA384
() and SHA512
() functions are not thread safe if
md is NULL.
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.
SHA1_Init(), SHA1_Update() and SHA1_Final() and equivalent
SHA224, SHA256,
SHA384
and SHA512
functions return 1 for success, 0 otherwise.
CONFORMING TO
US
Federal Information Processing Standard FIPS PUB 180-4
(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.