.\" $OpenBSD: SHA1.3,v 1.9 2024/06/01 12:35:23 tb Exp $ .\" OpenSSL 99d63d46 Oct 26 13:56:48 2016 -0400 .\" .\" This file was written by Ulf Moeller and .\" Matt Caswell . .\" Copyright (c) 2000, 2006, 2015 The OpenSSL Project. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in .\" the documentation and/or other materials provided with the .\" distribution. .\" .\" 3. All advertising materials mentioning features or use of this .\" software must display the following acknowledgment: .\" "This product includes software developed by the OpenSSL Project .\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)" .\" .\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to .\" endorse or promote products derived from this software without .\" prior written permission. For written permission, please contact .\" openssl-core@openssl.org. .\" .\" 5. Products derived from this software may not be called "OpenSSL" .\" nor may "OpenSSL" appear in their names without prior written .\" permission of the OpenSSL Project. .\" .\" 6. Redistributions of any form whatsoever must retain the following .\" acknowledgment: .\" "This product includes software developed by the OpenSSL Project .\" for use in the OpenSSL Toolkit (http://www.openssl.org/)" .\" .\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY .\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR .\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR .\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, .\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; .\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, .\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED .\" OF THE POSSIBILITY OF SUCH DAMAGE. .\" .Dd $Mdocdate: June 1 2024 $ .Dt SHA1 3 .Os .Sh NAME .Nm SHA1 , .Nm SHA1_Init , .Nm SHA1_Update , .Nm SHA1_Final , .Nm SHA224 , .Nm SHA224_Init , .Nm SHA224_Update , .Nm SHA224_Final , .Nm SHA256 , .Nm SHA256_Init , .Nm SHA256_Update , .Nm SHA256_Final , .Nm SHA384 , .Nm SHA384_Init , .Nm SHA384_Update , .Nm SHA384_Final , .Nm SHA512 , .Nm SHA512_Init , .Nm SHA512_Update , .Nm SHA512_Final .Nd Secure Hash Algorithm .Sh SYNOPSIS .In openssl/sha.h .Ft unsigned char * .Fo SHA1 .Fa "const unsigned char *d" .Fa "size_t n" .Fa "unsigned char *md" .Fc .Ft int .Fo SHA1_Init .Fa "SHA_CTX *c" .Fc .Ft int .Fo SHA1_Update .Fa "SHA_CTX *c" .Fa "const void *data" .Fa "size_t len" .Fc .Ft int .Fo SHA1_Final .Fa "unsigned char *md" .Fa "SHA_CTX *c" .Fc .Ft unsigned char * .Fo SHA224 .Fa "const unsigned char *d" .Fa "size_t n" .Fa "unsigned char *md" .Fc .Ft int .Fo SHA224_Init .Fa "SHA256_CTX *c" .Fc .Ft int .Fo SHA224_Update .Fa "SHA256_CTX *c" .Fa "const void *data" .Fa "size_t len" .Fc .Ft int .Fo SHA224_Final .Fa "unsigned char *md" .Fa "SHA256_CTX *c" .Fc .Ft unsigned char * .Fo SHA256 .Fa "const unsigned char *d" .Fa "size_t n" .Fa "unsigned char *md" .Fc .Ft int .Fo SHA256_Init .Fa "SHA256_CTX *c" .Fc .Ft int .Fo SHA256_Update .Fa "SHA256_CTX *c" .Fa "const void *data" .Fa "size_t len" .Fc .Ft int .Fo SHA256_Final .Fa "unsigned char *md" .Fa "SHA256_CTX *c" .Fc .Ft unsigned char * .Fo SHA384 .Fa "const unsigned char *d" .Fa "size_t n" .Fa "unsigned char *md" .Fc .Ft int .Fo SHA384_Init .Fa "SHA512_CTX *c" .Fc .Ft int .Fo SHA384_Update .Fa "SHA512_CTX *c" .Fa "const void *data" .Fa "size_t len" .Fc .Ft int .Fo SHA384_Final .Fa "unsigned char *md" .Fa "SHA512_CTX *c" .Fc .Ft unsigned char * .Fo SHA512 .Fa "const unsigned char *d" .Fa "size_t n" .Fa "unsigned char *md" .Fc .Ft int .Fo SHA512_Init .Fa "SHA512_CTX *c" .Fc .Ft int .Fo SHA512_Update .Fa "SHA512_CTX *c" .Fa "const void *data" .Fa "size_t len" .Fc .Ft int .Fo SHA512_Final .Fa "unsigned char *md" .Fa "SHA512_CTX *c" .Fc .Sh DESCRIPTION SHA-1 (Secure Hash Algorithm) is a cryptographic hash function with a 160-bit output. .Pp .Fn SHA1 computes the SHA-1 message digest of the .Fa n bytes at .Fa d and places it in .Fa md , which must have space for .Dv SHA_DIGEST_LENGTH == 20 bytes of output. .Pp The following functions may be used if the message is not completely stored in memory: .Pp .Fn SHA1_Init initializes a .Vt SHA_CTX structure. .Pp .Fn SHA1_Update can be called repeatedly with chunks of the message to be hashed .Pq Fa len No bytes at Fa data . .Pp .Fn SHA1_Final places the message digest in .Fa md , which must have space for .Dv SHA_DIGEST_LENGTH == 20 bytes of output, and erases the .Vt SHA_CTX . .Pp The SHA224, SHA256, SHA384, and SHA512 families of functions operate in the same way as the SHA1 functions. Note that SHA224 and SHA256 use a .Vt SHA256_CTX object instead of .Vt SHA_CTX , and SHA384 and SHA512 use .Vt SHA512_CTX . The buffer .Fa md must have space for the output from the SHA variant being used: .Dv SHA224_DIGEST_LENGTH , .Dv SHA256_DIGEST_LENGTH , .Dv SHA384_DIGEST_LENGTH , or .Dv SHA512_DIGEST_LENGTH bytes. .Pp Applications should use the higher level functions .Xr EVP_DigestInit 3 etc. instead of calling the hash functions directly. .Sh RETURN VALUES .Fn SHA1 , .Fn SHA224 , .Fn SHA256 , .Fn SHA384 , and .Fn SHA512 return a pointer to the hash value. The other functions return 1 for success or 0 otherwise. .Sh SEE ALSO .Xr EVP_DigestInit 3 , .Xr HMAC 3 , .Xr RIPEMD160 3 .Sh STANDARDS .Rs .%T Secure Hash Standard (SHS) .%R NIST FIPS Publication .%N 180-4 .%U https://doi.org/10.6028/NIST.FIPS.180-4 .%D 2015 .Re .Sh HISTORY .Fn SHA1 , .Fn SHA1_Init , .Fn SHA1_Update , and .Fn SHA1_Final first appeared in SSLeay 0.5.1 and have been available since .Ox 2.4 . .Pp The other functions first appeared in OpenSSL 0.9.8 and have been available since .Ox 4.5 . .Sh CAVEATS Other implementations allow .Fa md in .Fn SHA1 , .Fn SHA224 , .Fn SHA256 , .Fn SHA384 , and .Fn SHA512 to be .Dv NULL and return a static array, which is not thread safe.