1=pod 2 3=head1 NAME 4 5SHA1, SHA1_Init, SHA1_Update, SHA1_Final - Secure Hash Algorithm 6 7=head1 SYNOPSIS 8 9 #include <openssl/sha.h> 10 11 unsigned char *SHA1(const unsigned char *d, unsigned long n, 12 unsigned char *md); 13 14 int SHA1_Init(SHA_CTX *c); 15 int SHA1_Update(SHA_CTX *c, const void *data, 16 unsigned long len); 17 int SHA1_Final(unsigned char *md, SHA_CTX *c); 18 19=head1 DESCRIPTION 20 21SHA-1 (Secure Hash Algorithm) is a cryptographic hash function with a 22160 bit output. 23 24SHA1() computes the SHA-1 message digest of the B<n> 25bytes at B<d> and places it in B<md> (which must have space for 26SHA_DIGEST_LENGTH == 20 bytes of output). If B<md> is NULL, the digest 27is placed in a static array. 28 29The following functions may be used if the message is not completely 30stored in memory: 31 32SHA1_Init() initializes a B<SHA_CTX> structure. 33 34SHA1_Update() can be called repeatedly with chunks of the message to 35be hashed (B<len> bytes at B<data>). 36 37SHA1_Final() places the message digest in B<md>, which must have space 38for SHA_DIGEST_LENGTH == 20 bytes of output, and erases the B<SHA_CTX>. 39 40Applications should use the higher level functions 41L<EVP_DigestInit(3)|EVP_DigestInit(3)> 42etc. instead of calling the hash functions directly. 43 44The predecessor of SHA-1, SHA, is also implemented, but it should be 45used only when backward compatibility is required. 46 47=head1 RETURN VALUES 48 49SHA1() returns a pointer to the hash value. 50 51SHA1_Init(), SHA1_Update() and SHA1_Final() return 1 for success, 0 otherwise. 52 53=head1 CONFORMING TO 54 55SHA: US Federal Information Processing Standard FIPS PUB 180 (Secure Hash 56Standard), 57SHA-1: US Federal Information Processing Standard FIPS PUB 180-1 (Secure Hash 58Standard), 59ANSI X9.30 60 61=head1 SEE ALSO 62 63L<ripemd(3)|ripemd(3)>, L<hmac(3)|hmac(3)>, L<EVP_DigestInit(3)|EVP_DigestInit(3)> 64 65=head1 HISTORY 66 67SHA1(), SHA1_Init(), SHA1_Update() and SHA1_Final() are available in all 68versions of SSLeay and OpenSSL. 69 70=cut 71