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)> 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<EVP_DigestInit(3)> 98 99=head1 COPYRIGHT 100 101Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. 102 103Licensed under the OpenSSL license (the "License"). You may not use 104this file except in compliance with the License. You can obtain a copy 105in the file LICENSE in the source distribution or at 106L<https://www.openssl.org/source/license.html>. 107 108=cut 109