1=pod 2 3=head1 NAME 4 5SHA1, SHA1_Init, SHA1_Update, SHA1_Final, SHA224, SHA224_Init, SHA224_Update, 6SHA224_Final, SHA256, SHA256_Init, SHA256_Update, SHA256_Final, SHA384, 7SHA384_Init, SHA384_Update, SHA384_Final, SHA512, SHA512_Init, SHA512_Update, 8SHA512_Final - Secure Hash Algorithm 9 10=head1 SYNOPSIS 11 12 #include <openssl/sha.h> 13 14 int SHA1_Init(SHA_CTX *c); 15 int SHA1_Update(SHA_CTX *c, const void *data, size_t len); 16 int SHA1_Final(unsigned char *md, SHA_CTX *c); 17 unsigned char *SHA1(const unsigned char *d, size_t n, 18 unsigned char *md); 19 20 int SHA224_Init(SHA256_CTX *c); 21 int SHA224_Update(SHA256_CTX *c, const void *data, size_t len); 22 int SHA224_Final(unsigned char *md, SHA256_CTX *c); 23 unsigned char *SHA224(const unsigned char *d, size_t n, 24 unsigned char *md); 25 26 int SHA256_Init(SHA256_CTX *c); 27 int SHA256_Update(SHA256_CTX *c, const void *data, size_t len); 28 int SHA256_Final(unsigned char *md, SHA256_CTX *c); 29 unsigned char *SHA256(const unsigned char *d, size_t n, 30 unsigned char *md); 31 32 int SHA384_Init(SHA512_CTX *c); 33 int SHA384_Update(SHA512_CTX *c, const void *data, size_t len); 34 int SHA384_Final(unsigned char *md, SHA512_CTX *c); 35 unsigned char *SHA384(const unsigned char *d, size_t n, 36 unsigned char *md); 37 38 int SHA512_Init(SHA512_CTX *c); 39 int SHA512_Update(SHA512_CTX *c, const void *data, size_t len); 40 int SHA512_Final(unsigned char *md, SHA512_CTX *c); 41 unsigned char *SHA512(const unsigned char *d, size_t n, 42 unsigned char *md); 43 44=head1 DESCRIPTION 45 46Applications should use the higher level functions 47L<EVP_DigestInit(3)|EVP_DigestInit(3)> etc. instead of calling the hash 48functions directly. 49 50SHA-1 (Secure Hash Algorithm) is a cryptographic hash function with a 51160 bit output. 52 53SHA1() computes the SHA-1 message digest of the B<n> 54bytes at B<d> and places it in B<md> (which must have space for 55SHA_DIGEST_LENGTH == 20 bytes of output). If B<md> is NULL, the digest 56is placed in a static array. Note: setting B<md> to NULL is B<not thread safe>. 57 58The following functions may be used if the message is not completely 59stored in memory: 60 61SHA1_Init() initializes a B<SHA_CTX> structure. 62 63SHA1_Update() can be called repeatedly with chunks of the message to 64be hashed (B<len> bytes at B<data>). 65 66SHA1_Final() places the message digest in B<md>, which must have space 67for SHA_DIGEST_LENGTH == 20 bytes of output, and erases the B<SHA_CTX>. 68 69The SHA224, SHA256, SHA384 and SHA512 families of functions operate in the 70same way as for the SHA1 functions. Note that SHA224 and SHA256 use a 71B<SHA256_CTX> object instead of B<SHA_CTX>. SHA384 and SHA512 use B<SHA512_CTX>. 72The buffer B<md> must have space for the output from the SHA variant being used 73(defined by SHA224_DIGEST_LENGTH, SHA256_DIGEST_LENGTH, SHA384_DIGEST_LENGTH and 74SHA512_DIGEST_LENGTH). Also note that, as for the SHA1() function above, the 75SHA224(), SHA256(), SHA384() and SHA512() functions are not thread safe if 76B<md> is NULL. 77 78The predecessor of SHA-1, SHA, is also implemented, but it should be 79used only when backward compatibility is required. 80 81=head1 RETURN VALUES 82 83SHA1(), SHA224(), SHA256(), SHA384() and SHA512() return a pointer to the hash 84value. 85 86SHA1_Init(), SHA1_Update() and SHA1_Final() and equivalent SHA224, SHA256, 87SHA384 and SHA512 functions return 1 for success, 0 otherwise. 88 89=head1 CONFORMING TO 90 91US Federal Information Processing Standard FIPS PUB 180-4 (Secure Hash 92Standard), 93ANSI X9.30 94 95=head1 SEE ALSO 96 97L<ripemd(3)|ripemd(3)>, L<hmac(3)|hmac(3)>, L<EVP_DigestInit(3)|EVP_DigestInit(3)> 98 99=head1 HISTORY 100 101SHA1(), SHA1_Init(), SHA1_Update() and SHA1_Final() are available in all 102versions of SSLeay and OpenSSL. 103 104=cut 105