sha(3) OpenSSL sha(3)

NAME
       SHA1, SHA1Init, SHA1Update, SHA1Final - Secure Hash Algorithm

SYNOPSIS
        #include 

        unsigned char *SHA1(const unsigned char *d, unsigned long n,
                         unsigned char *md);

        void SHA1Init(SHACTX *c);
        void SHA1Update(SHACTX *c, const void *data,
                         unsigned long len);
        void SHA1Final(unsigned char *md, SHACTX *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 nn bytes at dd and places
       it in mmdd (which must have space for SHADIGESTLENGTH == 20 bytes of
       output). If mmdd 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:

       SHA1Init() initializes a SSHHAACCTTXX structure.

       SHA1Update() can be called repeatedly with chunks of the message to be
       hashed (lleenn bytes at ddaattaa).

       SHA1Final() places the message digest in mmdd, which must have space for
       SHADIGESTLENGTH == 20 bytes of output, and erases the SSHHAACCTTXX.

       Applications should use the higher level functions EVPDigestInit(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.

       SHA1Init(), SHA1Update() and SHA1Final() do not return values.

CCOONNFFOORRMMIINNGG TTOO
       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), EVPDigestInit(3)

HISTORY       SHA1(), SHA1Init(), SHA1Update() and SHA1Final() are available in
       all versions of SSLeay and OpenSSL.



0.9.7l                            2000-02-25                            sha(3)