1=pod 2 3=head1 NAME 4 5EVP_MD_meth_dup, 6EVP_MD_meth_new, EVP_MD_meth_free, EVP_MD_meth_set_input_blocksize, 7EVP_MD_meth_set_result_size, EVP_MD_meth_set_app_datasize, 8EVP_MD_meth_set_flags, EVP_MD_meth_set_init, EVP_MD_meth_set_update, 9EVP_MD_meth_set_final, EVP_MD_meth_set_copy, EVP_MD_meth_set_cleanup, 10EVP_MD_meth_set_ctrl, EVP_MD_meth_get_input_blocksize, 11EVP_MD_meth_get_result_size, EVP_MD_meth_get_app_datasize, 12EVP_MD_meth_get_flags, EVP_MD_meth_get_init, EVP_MD_meth_get_update, 13EVP_MD_meth_get_final, EVP_MD_meth_get_copy, EVP_MD_meth_get_cleanup, 14EVP_MD_meth_get_ctrl 15- Routines to build up EVP_MD methods 16 17=head1 SYNOPSIS 18 19 #include <openssl/evp.h> 20 21 EVP_MD *EVP_MD_meth_new(int md_type, int pkey_type); 22 void EVP_MD_meth_free(EVP_MD *md); 23 EVP_MD *EVP_MD_meth_dup(const EVP_MD *md); 24 25 int EVP_MD_meth_set_input_blocksize(EVP_MD *md, int blocksize); 26 int EVP_MD_meth_set_result_size(EVP_MD *md, int resultsize); 27 int EVP_MD_meth_set_app_datasize(EVP_MD *md, int datasize); 28 int EVP_MD_meth_set_flags(EVP_MD *md, unsigned long flags); 29 int EVP_MD_meth_set_init(EVP_MD *md, int (*init)(EVP_MD_CTX *ctx)); 30 int EVP_MD_meth_set_update(EVP_MD *md, int (*update)(EVP_MD_CTX *ctx, 31 const void *data, 32 size_t count)); 33 int EVP_MD_meth_set_final(EVP_MD *md, int (*final)(EVP_MD_CTX *ctx, 34 unsigned char *md)); 35 int EVP_MD_meth_set_copy(EVP_MD *md, int (*copy)(EVP_MD_CTX *to, 36 const EVP_MD_CTX *from)); 37 int EVP_MD_meth_set_cleanup(EVP_MD *md, int (*cleanup)(EVP_MD_CTX *ctx)); 38 int EVP_MD_meth_set_ctrl(EVP_MD *md, int (*ctrl)(EVP_MD_CTX *ctx, int cmd, 39 int p1, void *p2)); 40 41 int EVP_MD_meth_get_input_blocksize(const EVP_MD *md); 42 int EVP_MD_meth_get_result_size(const EVP_MD *md); 43 int EVP_MD_meth_get_app_datasize(const EVP_MD *md); 44 unsigned long EVP_MD_meth_get_flags(const EVP_MD *md); 45 int (*EVP_MD_meth_get_init(const EVP_MD *md))(EVP_MD_CTX *ctx); 46 int (*EVP_MD_meth_get_update(const EVP_MD *md))(EVP_MD_CTX *ctx, 47 const void *data, 48 size_t count); 49 int (*EVP_MD_meth_get_final(const EVP_MD *md))(EVP_MD_CTX *ctx, 50 unsigned char *md); 51 int (*EVP_MD_meth_get_copy(const EVP_MD *md))(EVP_MD_CTX *to, 52 const EVP_MD_CTX *from); 53 int (*EVP_MD_meth_get_cleanup(const EVP_MD *md))(EVP_MD_CTX *ctx); 54 int (*EVP_MD_meth_get_ctrl(const EVP_MD *md))(EVP_MD_CTX *ctx, int cmd, 55 int p1, void *p2); 56 57=head1 DESCRIPTION 58 59The B<EVP_MD> type is a structure for digest method implementation. 60It can also have associated public/private key signing and verifying 61routines. 62 63EVP_MD_meth_new() creates a new B<EVP_MD> structure. 64 65EVP_MD_meth_dup() creates a copy of B<md>. 66 67EVP_MD_meth_free() destroys a B<EVP_MD> structure. 68 69EVP_MD_meth_set_input_blocksize() sets the internal input block size 70for the method B<md> to B<blocksize> bytes. 71 72EVP_MD_meth_set_result_size() sets the size of the result that the 73digest method in B<md> is expected to produce to B<resultsize> bytes. 74 75The digest method may have its own private data, which OpenSSL will 76allocate for it. EVP_MD_meth_set_app_datasize() should be used to 77set the size for it to B<datasize>. 78 79EVP_MD_meth_set_flags() sets the flags to describe optional 80behaviours in the particular B<md>. Several flags can be or'd 81together. The available flags are: 82 83=over 4 84 85=item EVP_MD_FLAG_ONESHOT 86 87This digest method can only handle one block of input. 88 89=item EVP_MD_FLAG_XOF 90 91This digest method is an extensible-output function (XOF) and supports 92the B<EVP_MD_CTRL_XOF_LEN> control. 93 94=item EVP_MD_FLAG_DIGALGID_NULL 95 96When setting up a DigestAlgorithmIdentifier, this flag will have the 97parameter set to NULL by default. Use this for PKCS#1. I<Note: if 98combined with EVP_MD_FLAG_DIGALGID_ABSENT, the latter will override.> 99 100=item EVP_MD_FLAG_DIGALGID_ABSENT 101 102When setting up a DigestAlgorithmIdentifier, this flag will have the 103parameter be left absent by default. I<Note: if combined with 104EVP_MD_FLAG_DIGALGID_NULL, the latter will be overridden.> 105 106=item EVP_MD_FLAG_DIGALGID_CUSTOM 107 108Custom DigestAlgorithmIdentifier handling via ctrl, with 109B<EVP_MD_FLAG_DIGALGID_ABSENT> as default. I<Note: if combined with 110EVP_MD_FLAG_DIGALGID_NULL, the latter will be overridden.> 111Currently unused. 112 113=item EVP_MD_FLAG_FIPS 114 115This digest method is suitable for use in FIPS mode. 116Currently unused. 117 118=back 119 120EVP_MD_meth_set_init() sets the digest init function for B<md>. 121The digest init function is called by EVP_Digest(), EVP_DigestInit(), 122EVP_DigestInit_ex(), EVP_SignInit, EVP_SignInit_ex(), EVP_VerifyInit() 123and EVP_VerifyInit_ex(). 124 125EVP_MD_meth_set_update() sets the digest update function for B<md>. 126The digest update function is called by EVP_Digest(), EVP_DigestUpdate() and 127EVP_SignUpdate(). 128 129EVP_MD_meth_set_final() sets the digest final function for B<md>. 130The digest final function is called by EVP_Digest(), EVP_DigestFinal(), 131EVP_DigestFinal_ex(), EVP_SignFinal() and EVP_VerifyFinal(). 132 133EVP_MD_meth_set_copy() sets the function for B<md> to do extra 134computations after the method's private data structure has been copied 135from one B<EVP_MD_CTX> to another. If all that's needed is to copy 136the data, there is no need for this copy function. 137Note that the copy function is passed two B<EVP_MD_CTX *>, the private 138data structure is then available with EVP_MD_CTX_md_data(). 139This copy function is called by EVP_MD_CTX_copy() and 140EVP_MD_CTX_copy_ex(). 141 142EVP_MD_meth_set_cleanup() sets the function for B<md> to do extra 143cleanup before the method's private data structure is cleaned out and 144freed. 145Note that the cleanup function is passed a B<EVP_MD_CTX *>, the 146private data structure is then available with EVP_MD_CTX_md_data(). 147This cleanup function is called by EVP_MD_CTX_reset() and 148EVP_MD_CTX_free(). 149 150EVP_MD_meth_set_ctrl() sets the control function for B<md>. 151See L<EVP_MD_CTX_ctrl(3)> for the available controls. 152 153EVP_MD_meth_get_input_blocksize(), EVP_MD_meth_get_result_size(), 154EVP_MD_meth_get_app_datasize(), EVP_MD_meth_get_flags(), 155EVP_MD_meth_get_init(), EVP_MD_meth_get_update(), 156EVP_MD_meth_get_final(), EVP_MD_meth_get_copy(), 157EVP_MD_meth_get_cleanup() and EVP_MD_meth_get_ctrl() are all used 158to retrieve the method data given with the EVP_MD_meth_set_*() 159functions above. 160 161=head1 RETURN VALUES 162 163EVP_MD_meth_new() and EVP_MD_meth_dup() return a pointer to a newly 164created B<EVP_MD>, or NULL on failure. 165All EVP_MD_meth_set_*() functions return 1. 166EVP_MD_get_input_blocksize(), EVP_MD_meth_get_result_size(), 167EVP_MD_meth_get_app_datasize() and EVP_MD_meth_get_flags() return the 168indicated sizes or flags. 169All other EVP_CIPHER_meth_get_*() functions return pointers to their 170respective B<md> function. 171 172=head1 SEE ALSO 173 174L<EVP_DigestInit(3)>, L<EVP_SignInit(3)>, L<EVP_VerifyInit(3)> 175 176=head1 HISTORY 177 178The B<EVP_MD> structure was openly available in OpenSSL before version 1791.1. The functions described here were added in OpenSSL 1.1. 180 181=head1 COPYRIGHT 182 183Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved. 184 185Licensed under the OpenSSL license (the "License"). You may not use 186this file except in compliance with the License. You can obtain a copy 187in the file LICENSE in the source distribution or at 188L<https://www.openssl.org/source/license.html>. 189 190=cut 191