sha 3 2007-03-06 0.9.9-dev OpenSSL

### NAME

SHA1, SHA1_Init, SHA1_Update, SHA1_Final - Secure Hash Algorithm

### LIBRARY

libcrypto, -lcrypto

### SYNOPSIS

     #include

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

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

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

SHA1() returns a pointer to the hash value.

SHA1_Init(), SHA1_Update() and SHA1_Final() return 1 for success, 0 otherwise.

### CONFORMING TO

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

openssl_ripemd(3), openssl_hmac(3), EVP_DigestInit(3)

### HISTORY

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