.\" $OpenBSD: EVP_MD_meth_new.3,v 1.2 2023/07/09 06:47:51 tb Exp $ .\" selective merge up to: .\" OpenSSL man3/EVP_MD_meth_new 0388d212 Dec 14 12:47:07 2018 -0800 .\" .\" This file was written by Richard Levitte .\" Copyright (c) 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: July 9 2023 $ .Dt EVP_MD_METH_NEW 3 .Os .Sh NAME .Nm EVP_MD_meth_dup , .Nm EVP_MD_meth_new , .Nm EVP_MD_meth_free , .Nm EVP_MD_meth_set_input_blocksize , .Nm EVP_MD_meth_set_result_size , .Nm EVP_MD_meth_set_app_datasize , .Nm EVP_MD_meth_set_flags , .Nm EVP_MD_meth_set_init , .Nm EVP_MD_meth_set_update , .Nm EVP_MD_meth_set_final , .Nm EVP_MD_meth_set_copy , .Nm EVP_MD_meth_set_cleanup , .Nm EVP_MD_meth_set_ctrl .Nd Routines to build up EVP_MD methods .Sh SYNOPSIS .In openssl/evp.h .Ft EVP_MD * .Fo EVP_MD_meth_new .Fa "int md_type" .Fa "int pkey_type" .Fc .Ft void .Fo EVP_MD_meth_free .Fa "EVP_MD *md" .Fc .Ft EVP_MD * .Fo EVP_MD_meth_dup .Fa "const EVP_MD *md" .Fc .Ft int .Fo EVP_MD_meth_set_input_blocksize .Fa "EVP_MD *md" .Fa "int blocksize" .Fc .Ft int .Fo EVP_MD_meth_set_result_size .Fa "EVP_MD *md" .Fa "int resultsize" .Fc .Ft int .Fo EVP_MD_meth_set_app_datasize .Fa "EVP_MD *md" .Fa "int datasize" .Fc .Ft int .Fo EVP_MD_meth_set_flags .Fa "EVP_MD *md" .Fa "unsigned long flags" .Fc .Ft int .Fo EVP_MD_meth_set_init .Fa "EVP_MD *md" .Fa "int (*init)(EVP_MD_CTX *ctx)" .Fc .Ft int .Fo EVP_MD_meth_set_update .Fa "EVP_MD *md" .Fa "int (*update)(EVP_MD_CTX *ctx, const void *data, size_t count)" .Fc .Ft int .Fo EVP_MD_meth_set_final .Fa "EVP_MD *md" .Fa "int (*final)(EVP_MD_CTX *ctx, unsigned char *md)" .Fc .Ft int .Fo EVP_MD_meth_set_copy .Fa "EVP_MD *md" .Fa "int (*copy)(EVP_MD_CTX *to, const EVP_MD_CTX *from)" .Fc .Ft int .Fo EVP_MD_meth_set_cleanup .Fa "EVP_MD *md" .Fa "int (*cleanup)(EVP_MD_CTX *ctx)" .Fc .Ft int .Fo EVP_MD_meth_set_ctrl .Fa "EVP_MD *md" .Fa "int (*ctrl)(EVP_MD_CTX *ctx, int cmd, int p1, void *p2)" .Fc .Sh DESCRIPTION The .Vt EVP_MD type is a structure for digest method implementation. It can also have associated public/private key signing and verifying routines. .Pp .Fn EVP_MD_meth_new creates a new .Vt EVP_MD structure. .Pp .Fn EVP_MD_meth_dup creates a copy of .Fa md . .Pp .Fn EVP_MD_meth_free destroys a .Vt EVP_MD structure. .Pp .Fn EVP_MD_meth_set_input_blocksize sets the internal input block size for the method .Fa md to .Fa blocksize bytes. .Pp .Fn EVP_MD_meth_set_result_size sets the size of the result that the digest method in .Fa md is expected to produce to .Fa resultsize bytes. .Pp The digest method may have its own private data, which OpenSSL will allocate for it. .Fn EVP_MD_meth_set_app_datasize should be used to set the size for it to .Fa datasize . .Pp .Fn EVP_MD_meth_set_flags sets the flags to describe optional behaviours in the particular .Fa md . Several flags can be or'd together. The available flags are: .Bl -tag -width Ds .It EVP_MD_FLAG_ONESHOT This digest method can only handle one block of input. .It EVP_MD_FLAG_DIGALGID_NULL When setting up a DigestAlgorithmIdentifier, this flag will have the parameter set to NULL by default. Use this for PKCS#1. .Em Note: if combined with EVP_MD_FLAG_DIGALGID_ABSENT, the latter will override. .It EVP_MD_FLAG_DIGALGID_ABSENT When setting up a DigestAlgorithmIdentifier, this flag will have the parameter be left absent by default. .Em Note: if combined with EVP_MD_FLAG_DIGALGID_NULL, the latter will be overridden. .It EVP_MD_FLAG_DIGALGID_CUSTOM Custom DigestAlgorithmIdentifier handling via ctrl, with .Sy EVP_MD_FLAG_DIGALGID_ABSENT as default. .Em Note: if combined with EVP_MD_FLAG_DIGALGID_NULL, the latter will be overridden. Currently unused. .It EVP_MD_FLAG_FIPS This digest method is suitable for use in FIPS mode. Currently unused. .El .Pp .Fn EVP_MD_meth_set_init sets the digest init function for .Fa md . The digest init function is called by .Xr EVP_Digest 3 , .Xr EVP_DigestInit 3 , .Xr EVP_DigestInit_ex 3 , EVP_SignInit, .Xr EVP_SignInit_ex 3 , .Xr EVP_VerifyInit 3 and .Xr EVP_VerifyInit_ex 3 . .Pp .Fn EVP_MD_meth_set_update sets the digest update function for .Fa md . The digest update function is called by .Xr EVP_Digest 3 , .Xr EVP_DigestUpdate 3 and .Xr EVP_SignUpdate 3 . .Pp .Fn EVP_MD_meth_set_final sets the digest final function for .Fa md . The digest final function is called by .Xr EVP_Digest 3 , .Xr EVP_DigestFinal 3 , .Xr EVP_DigestFinal_ex 3 , .Xr EVP_SignFinal 3 and .Xr EVP_VerifyFinal 3 . .Pp .Fn EVP_MD_meth_set_copy sets the function for .Fa md to do extra computations after the method's private data structure has been copied from one .Vt EVP_MD_CTX object to another. If all that's needed is to copy the data, there is no need for this copy function. The copy function is passed two .Vt EVP_MD_CTX objects, the private data structure is then available with .Xr EVP_MD_CTX_md_data 3 . This copy function is called by .Xr EVP_MD_CTX_copy 3 and .Xr EVP_MD_CTX_copy_ex 3 . .Pp .Fn EVP_MD_meth_set_cleanup sets the function for .Fa md to do extra cleanup before the method's private data structure is cleaned out and freed. The cleanup function is passed an .Vt EVP_MD_CTX object, the private data structure is then available with .Xr EVP_MD_CTX_md_data 3 . This cleanup function is called by .Xr EVP_MD_CTX_reset 3 and .Xr EVP_MD_CTX_free 3 . .Pp .Fn EVP_MD_meth_set_ctrl sets the control function for .Fa md . See .Xr EVP_MD_CTX_ctrl 3 for the available controls. .Sh RETURN VALUES .Fn EVP_MD_meth_new and .Fn EVP_MD_meth_dup return a pointer to a newly created .Vt EVP_MD , or NULL on failure. All .Fn EVP_MD_meth_set_* functions return 1. .Sh SEE ALSO .Xr EVP_DigestInit 3 , .Xr EVP_SignInit 3 , .Xr EVP_VerifyInit 3 .Sh HISTORY All these functions first appeared in OpenSSL 1.1.0 and have been available since .Ox 7.1 .