SHA256_Final(3)

sha(3)                       OpenSSL                       sha(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>

      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

1.0.2t               Last change: 2019-09-10                    1

sha(3)                       OpenSSL                       sha(3)

     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.

1.0.2t               Last change: 2019-09-10                    2