SHA1(3)

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
EVP_DigestInit(3), HMAC(3), RIPEMD160(3)

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.