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			180 lines
		
	
	
		
			7.1 KiB
		
	
	
	
		
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			180 lines
		
	
	
		
			7.1 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
| =pod
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| 
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| =head1 NAME
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| 
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| EVP_MD_meth_dup,
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| EVP_MD_meth_new, EVP_MD_meth_free, EVP_MD_meth_set_input_blocksize,
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| EVP_MD_meth_set_result_size, EVP_MD_meth_set_app_datasize,
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| EVP_MD_meth_set_flags, EVP_MD_meth_set_init, EVP_MD_meth_set_update,
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| EVP_MD_meth_set_final, EVP_MD_meth_set_copy, EVP_MD_meth_set_cleanup,
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| EVP_MD_meth_set_ctrl, EVP_MD_meth_get_input_blocksize,
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| EVP_MD_meth_get_result_size, EVP_MD_meth_get_app_datasize,
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| EVP_MD_meth_get_flags, EVP_MD_meth_get_init, EVP_MD_meth_get_update,
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| EVP_MD_meth_get_final, EVP_MD_meth_get_copy, EVP_MD_meth_get_cleanup,
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| EVP_MD_meth_get_ctrl
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| - Routines to build up EVP_MD methods
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| 
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| =head1 SYNOPSIS
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| 
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|  #include <openssl/evp.h>
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| 
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|  EVP_MD *EVP_MD_meth_new(int md_type, int pkey_type);
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|  void EVP_MD_meth_free(EVP_MD *md);
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|  EVP_MD *EVP_MD_meth_dup(const EVP_MD *md);
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| 
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|  int EVP_MD_meth_set_input_blocksize(EVP_MD *md, int blocksize);
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|  int EVP_MD_meth_set_result_size(EVP_MD *md, int resultsize);
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|  int EVP_MD_meth_set_app_datasize(EVP_MD *md, int datasize);
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|  int EVP_MD_meth_set_flags(EVP_MD *md, unsigned long flags);
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|  int EVP_MD_meth_set_init(EVP_MD *md, int (*init)(EVP_MD_CTX *ctx));
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|  int EVP_MD_meth_set_update(EVP_MD *md, int (*update)(EVP_MD_CTX *ctx,
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|                                                       const void *data,
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|                                                       size_t count));
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|  int EVP_MD_meth_set_final(EVP_MD *md, int (*final)(EVP_MD_CTX *ctx,
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|                                                     unsigned char *md));
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|  int EVP_MD_meth_set_copy(EVP_MD *md, int (*copy)(EVP_MD_CTX *to,
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|                                                   const EVP_MD_CTX *from));
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|  int EVP_MD_meth_set_cleanup(EVP_MD *md, int (*cleanup)(EVP_MD_CTX *ctx));
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|  int EVP_MD_meth_set_ctrl(EVP_MD *md, int (*ctrl)(EVP_MD_CTX *ctx, int cmd,
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|                                                   int p1, void *p2));
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| 
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|  int EVP_MD_meth_get_input_blocksize(const EVP_MD *md);
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|  int EVP_MD_meth_get_result_size(const EVP_MD *md);
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|  int EVP_MD_meth_get_app_datasize(const EVP_MD *md);
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|  unsigned long EVP_MD_meth_get_flags(const EVP_MD *md);
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|  int (*EVP_MD_meth_get_init(const EVP_MD *md))(EVP_MD_CTX *ctx);
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|  int (*EVP_MD_meth_get_update(const EVP_MD *md))(EVP_MD_CTX *ctx,
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|                                                  const void *data,
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|                                                  size_t count);
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|  int (*EVP_MD_meth_get_final(const EVP_MD *md))(EVP_MD_CTX *ctx,
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|                                                 unsigned char *md);
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|  int (*EVP_MD_meth_get_copy(const EVP_MD *md))(EVP_MD_CTX *to,
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|                                                const EVP_MD_CTX *from);
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|  int (*EVP_MD_meth_get_cleanup(const EVP_MD *md))(EVP_MD_CTX *ctx);
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|  int (*EVP_MD_meth_get_ctrl(const EVP_MD *md))(EVP_MD_CTX *ctx, int cmd,
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|                                                int p1, void *p2);
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| 
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| =head1 DESCRIPTION
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| 
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| The B<EVP_MD> type is a structure for digest method implementation.
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| It can also have associated public/private key signing and verifying
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| routines.
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| 
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| EVP_MD_meth_new() creates a new B<EVP_MD> structure.
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| 
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| EVP_MD_meth_dup() creates a copy of B<md>.
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| 
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| EVP_MD_meth_free() destroys a B<EVP_MD> structure.
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| 
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| EVP_MD_meth_set_input_blocksize() sets the internal input block size
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| for the method B<md> to B<blocksize> bytes.
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| 
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| EVP_MD_meth_set_result_size() sets the size of the result that the
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| digest method in B<md> is expected to produce to B<resultsize> bytes.
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| 
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| The digest method may have its own private data, which OpenSSL will
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| allocate for it.  EVP_MD_meth_set_app_datasize() should be used to
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| set the size for it to B<datasize>.
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| 
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| EVP_MD_meth_set_flags() sets the flags to describe optional
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| behaviours in the particular B<md>.  Several flags can be or'd
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| together.  The available flags are:
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| 
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| =over 4
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| 
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| =item EVP_MD_FLAG_ONESHOT
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| 
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| This digest method can only handles one block of input.
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| 
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| =item EVP_MD_FLAG_DIGALGID_NULL
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| 
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| When setting up a DigestAlgorithmIdentifier, this flag will have the
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| parameter set to NULL by default.  Use this for PKCS#1.  I<Note: if
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| combined with EVP_MD_FLAG_DIGALGID_ABSENT, the latter will override.>
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| 
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| =item EVP_MD_FLAG_DIGALGID_ABSENT
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| 
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| When setting up a DigestAlgorithmIdentifier, this flag will have the
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| parameter be left absent by default.  I<Note: if combined with
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| EVP_MD_FLAG_DIGALGID_NULL, the latter will be overridden.>
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| 
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| =item EVP_MD_FLAG_DIGALGID_CUSTOM
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| 
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| Custom DigestAlgorithmIdentifier handling via ctrl, with
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| B<EVP_MD_FLAG_DIGALGID_ABSENT> as default.  I<Note: if combined with
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| EVP_MD_FLAG_DIGALGID_NULL, the latter will be overridden.>
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| Currently unused.
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| 
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| =back
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| 
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| EVP_MD_meth_set_init() sets the digest init function for B<md>.
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| The digest init function is called by EVP_DigestInit(),
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| EVP_DigestInit_ex(), EVP_SignInit, EVP_SignInit_ex(), EVP_VerifyInit()
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| and EVP_VerifyInit_ex().
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| 
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| EVP_MD_meth_set_update() sets the digest update function for B<md>.
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| The digest update function is called by EVP_DigestUpdate(),
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| EVP_SignUpdate().
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| 
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| EVP_MD_meth_set_final() sets the digest final function for B<md>.
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| The digest final function is called by EVP_DigestFinal(),
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| EVP_DigestFinal_ex(), EVP_SignFinal() and EVP_VerifyFinal().
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| 
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| EVP_MD_meth_set_copy() sets the function for B<md> to do extra
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| computations after the method's private data structure has been copied
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| from one B<EVP_MD_CTX> to another.  If all that's needed is to copy
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| the data, there is no need for this copy function.
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| Note that the copy function is passed two B<EVP_MD_CTX *>, the private
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| data structure is then available with EVP_MD_CTX_md_data().
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| This copy function is called by EVP_MD_CTX_copy() and
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| EVP_MD_CTX_copy_ex().
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| 
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| EVP_MD_meth_set_cleanup() sets the function for B<md> to do extra
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| cleanup before the method's private data structure is cleaned out and
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| freed.
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| Note that the cleanup function is passed a B<EVP_MD_CTX *>, the
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| private data structure is then available with EVP_MD_CTX_md_data().
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| This cleanup function is called by EVP_MD_CTX_reset() and
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| EVP_MD_CTX_free().
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| 
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| EVP_MD_meth_set_ctrl() sets the control function for B<md>.
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| 
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| EVP_MD_meth_get_input_blocksize(), EVP_MD_meth_get_result_size(),
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| EVP_MD_meth_get_app_datasize(), EVP_MD_meth_get_flags(),
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| EVP_MD_meth_get_init(), EVP_MD_meth_get_update(),
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| EVP_MD_meth_get_final(), EVP_MD_meth_get_copy(),
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| EVP_MD_meth_get_cleanup() and EVP_MD_meth_get_ctrl() are all used
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| to retrieve the method data given with the EVP_MD_meth_set_*()
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| functions above.
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| 
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| =head1 RETURN VALUES
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| 
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| EVP_MD_meth_new() and EVP_MD_meth_dup() return a pointer to a newly
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| created B<EVP_MD>, or NULL on failure.
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| All EVP_MD_meth_set_*() functions return 1.
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| EVP_MD_get_input_blocksize(), EVP_MD_meth_get_result_size(),
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| EVP_MD_meth_get_app_datasize() and EVP_MD_meth_get_flags() return the
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| indicated sizes or flags.
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| All other EVP_CIPHER_meth_get_*() functions return pointers to their
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| respective B<md> function.
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| 
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| =head1 SEE ALSO
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| 
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| L<EVP_DigestInit(3)>, L<EVP_SignInit(3)>, L<EVP_VerifyInit(3)>
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| 
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| =head1 HISTORY
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| 
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| The B<EVP_MD> structure was openly available in OpenSSL before version
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| 1.1.  The functions described here were added in OpenSSL 1.1.
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| 
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| =head1 COPYRIGHT
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| 
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| Copyright 2015-2017 The OpenSSL Project Authors. All Rights Reserved.
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| 
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| Licensed under the OpenSSL license (the "License").  You may not use
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| this file except in compliance with the License.  You can obtain a copy
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| in the file LICENSE in the source distribution or at
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| L<https://www.openssl.org/source/license.html>.
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| 
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| =cut
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