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EVP_MD_meth_new(3)                  OpenSSL                 EVP_MD_meth_new(3)



NAME
       EVP_MD_meth_dup, EVP_MD_meth_new, EVP_MD_meth_free,
       EVP_MD_meth_set_input_blocksize, EVP_MD_meth_set_result_size,
       EVP_MD_meth_set_app_datasize, EVP_MD_meth_set_flags,
       EVP_MD_meth_set_init, EVP_MD_meth_set_update, EVP_MD_meth_set_final,
       EVP_MD_meth_set_copy, EVP_MD_meth_set_cleanup, EVP_MD_meth_set_ctrl,
       EVP_MD_meth_get_input_blocksize, EVP_MD_meth_get_result_size,
       EVP_MD_meth_get_app_datasize, EVP_MD_meth_get_flags,
       EVP_MD_meth_get_init, EVP_MD_meth_get_update, EVP_MD_meth_get_final,
       EVP_MD_meth_get_copy, EVP_MD_meth_get_cleanup, EVP_MD_meth_get_ctrl -
       Routines to build up EVP_MD methods

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/evp.h>

        EVP_MD *EVP_MD_meth_new(int md_type, int pkey_type);
        void EVP_MD_meth_free(EVP_MD *md);
        EVP_MD *EVP_MD_meth_dup(const EVP_MD *md);

        int EVP_MD_meth_set_input_blocksize(EVP_MD *md, int blocksize);
        int EVP_MD_meth_set_result_size(EVP_MD *md, int resultsize);
        int EVP_MD_meth_set_app_datasize(EVP_MD *md, int datasize);
        int EVP_MD_meth_set_flags(EVP_MD *md, unsigned long flags);
        int EVP_MD_meth_set_init(EVP_MD *md, int (*init)(EVP_MD_CTX *ctx));
        int EVP_MD_meth_set_update(EVP_MD *md, int (*update)(EVP_MD_CTX *ctx,
                                                             const void *data,
                                                             size_t count));
        int EVP_MD_meth_set_final(EVP_MD *md, int (*final)(EVP_MD_CTX *ctx,
                                                           unsigned char *md));
        int EVP_MD_meth_set_copy(EVP_MD *md, int (*copy)(EVP_MD_CTX *to,
                                                         const EVP_MD_CTX *from));
        int EVP_MD_meth_set_cleanup(EVP_MD *md, int (*cleanup)(EVP_MD_CTX *ctx));
        int EVP_MD_meth_set_ctrl(EVP_MD *md, int (*ctrl)(EVP_MD_CTX *ctx, int cmd,
                                                         int p1, void *p2));

        int EVP_MD_meth_get_input_blocksize(const EVP_MD *md);
        int EVP_MD_meth_get_result_size(const EVP_MD *md);
        int EVP_MD_meth_get_app_datasize(const EVP_MD *md);
        unsigned long EVP_MD_meth_get_flags(const EVP_MD *md);
        int (*EVP_MD_meth_get_init(const EVP_MD *md))(EVP_MD_CTX *ctx);
        int (*EVP_MD_meth_get_update(const EVP_MD *md))(EVP_MD_CTX *ctx,
                                                        const void *data,
                                                        size_t count);
        int (*EVP_MD_meth_get_final(const EVP_MD *md))(EVP_MD_CTX *ctx,
                                                       unsigned char *md);
        int (*EVP_MD_meth_get_copy(const EVP_MD *md))(EVP_MD_CTX *to,
                                                      const EVP_MD_CTX *from);
        int (*EVP_MD_meth_get_cleanup(const EVP_MD *md))(EVP_MD_CTX *ctx);
        int (*EVP_MD_meth_get_ctrl(const EVP_MD *md))(EVP_MD_CTX *ctx, int cmd,
                                                      int p1, void *p2);

DESCRIPTION
       The EVP_MD type is a structure for digest method implementation.  It
       can also have associated public/private key signing and verifying
       routines.

       EVP_MD_meth_new() creates a new EVP_MD structure.

       EVP_MD_meth_dup() creates a copy of md.

       EVP_MD_meth_free() destroys a EVP_MD structure.

       EVP_MD_meth_set_input_blocksize() sets the internal input block size
       for the method md to blocksize bytes.

       EVP_MD_meth_set_result_size() sets the size of the result that the
       digest method in md is expected to produce to resultsize bytes.

       The digest method may have its own private data, which OpenSSL will
       allocate for it.  EVP_MD_meth_set_app_datasize() should be used to set
       the size for it to datasize.

       EVP_MD_meth_set_flags() sets the flags to describe optional behaviours
       in the particular md.  Several flags can be or'd together.  The
       available flags are:

       EVP_MD_FLAG_ONESHOT
           This digest method can only handles one block of input.

       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.  Note:
           if combined with EVP_MD_FLAG_DIGALGID_ABSENT, the latter will
           override.

       EVP_MD_FLAG_DIGALGID_ABSENT
           When setting up a DigestAlgorithmIdentifier, this flag will have
           the parameter be left absent by default.  Note: if combined with
           EVP_MD_FLAG_DIGALGID_NULL, the latter will be overridden.

       EVP_MD_FLAG_DIGALGID_CUSTOM
           Custom DigestAlgorithmIdentifier handling via ctrl, with
           EVP_MD_FLAG_DIGALGID_ABSENT as default.  Note: if combined with
           EVP_MD_FLAG_DIGALGID_NULL, the latter will be overridden. Currently
           unused.

       EVP_MD_meth_set_init() sets the digest init function for md.  The
       digest init function is called by EVP_DigestInit(),
       EVP_DigestInit_ex(), EVP_SignInit, EVP_SignInit_ex(), EVP_VerifyInit()
       and EVP_VerifyInit_ex().

       EVP_MD_meth_set_update() sets the digest update function for md.  The
       digest update function is called by EVP_DigestUpdate(),
       EVP_SignUpdate().

       EVP_MD_meth_set_final() sets the digest final function for md.  The
       digest final function is called by EVP_DigestFinal(),
       EVP_DigestFinal_ex(), EVP_SignFinal() and EVP_VerifyFinal().

       EVP_MD_meth_set_copy() sets the function for md to do extra
       computations after the method's private data structure has been copied
       from one EVP_MD_CTX to another.  If all that's needed is to copy the
       data, there is no need for this copy function.  Note that the copy
       function is passed two EVP_MD_CTX *, the private data structure is then
       available with EVP_MD_CTX_md_data().  This copy function is called by
       EVP_MD_CTX_copy() and EVP_MD_CTX_copy_ex().

       EVP_MD_meth_set_cleanup() sets the function for md to do extra cleanup
       before the method's private data structure is cleaned out and freed.
       Note that the cleanup function is passed a EVP_MD_CTX *, the private
       data structure is then available with EVP_MD_CTX_md_data().  This
       cleanup function is called by EVP_MD_CTX_reset() and EVP_MD_CTX_free().

       EVP_MD_meth_set_ctrl() sets the control function for md.

       EVP_MD_meth_get_input_blocksize(), EVP_MD_meth_get_result_size(),
       EVP_MD_meth_get_app_datasize(), EVP_MD_meth_get_flags(),
       EVP_MD_meth_get_init(), EVP_MD_meth_get_update(),
       EVP_MD_meth_get_final(), EVP_MD_meth_get_copy(),
       EVP_MD_meth_get_cleanup() and EVP_MD_meth_get_ctrl() are all used to
       retrieve the method data given with the EVP_MD_meth_set_*() functions
       above.

RETURN VALUES
       EVP_MD_meth_new() and EVP_MD_meth_dup() return a pointer to a newly
       created EVP_MD, or NULL on failure.  All EVP_MD_meth_set_*() functions
       return 1.  EVP_MD_get_input_blocksize(), EVP_MD_meth_get_result_size(),
       EVP_MD_meth_get_app_datasize() and EVP_MD_meth_get_flags() return the
       indicated sizes or flags.  All other EVP_CIPHER_meth_get_*() functions
       return pointers to their respective md function.

SEE ALSO
       EVP_DigestInit(3), EVP_SignInit(3), EVP_VerifyInit(3)

HISTORY
       The EVP_MD structure was openly available in OpenSSL before version
       1.1.  The functions described here were added in OpenSSL 1.1.

COPYRIGHT
       Copyright 2015-2017 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.



1.1.1                             2018-09-17                EVP_MD_meth_new(3)