NAME    [Toc]    [Back]

       SHA1, SHA1_Init, SHA1_Update, SHA1_Final - Secure Hash
       Algorithm

SYNOPSIS    [Toc]    [Back]

        #include <openssl/sha.h>

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

        void SHA1_Init(SHA_CTX *c);
        void SHA1_Update(SHA_CTX *c, const void *data,
                         unsigned long len);
        void SHA1_Final(unsigned char *md, SHA_CTX *c);

DESCRIPTION    [Toc]    [Back]

       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.

       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.

       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    [Toc]    [Back]

       SHA1() returns a pointer to the hash value.

       SHA1_Init(), SHA1_Update() and SHA1_Final() do not return
       values.

CONFORMING TO    [Toc]    [Back]

       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    [Toc]    [Back]

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

HISTORY    [Toc]    [Back]

       SHA1(), SHA1_Init(), SHA1_Update() and SHA1_Final() are
       available in all versions of SSLeay and OpenSSL.


OpenBSD 3.6                 2000-04-03                          2