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SM2(7)				    OpenSSL				SM2(7)

       SM2 - Chinese SM2 signature and encryption algorithm support

       The SM2 algorithm was first defined by the Chinese national standard
       GM/T 0003-2012 and was later standardized by ISO	as ISO/IEC 14888. SM2
       is actually an elliptic curve based algorithm. The current
       implementation in OpenSSL supports both signature and encryption
       schemes via the EVP interface.

       When doing the SM2 signature algorithm, it requires a distinguishing
       identifier to form the message prefix which is hashed before the	real
       message is hashed.

       SM2 signatures can be generated by using	the 'DigestSign' series	of
       APIs, for instance, EVP_DigestSignInit(), EVP_DigestSignUpdate()	and
       EVP_DigestSignFinal().  Ditto for the verification process by calling
       the 'DigestVerify' series of APIs.

       There are several special steps that need to be done before computing
       an SM2 signature.

       The EVP_PKEY structure will default to using ECDSA for signatures when
       it is created. It should	be set to EVP_PKEY_SM2 by calling:

	EVP_PKEY_set_alias_type(pkey, EVP_PKEY_SM2);

       Then an ID should be set	by calling:

	EVP_PKEY_CTX_set1_id(pctx, id, id_len);

       When calling the	EVP_DigestSignInit() or	EVP_DigestVerifyInit()
       functions, a preallocated EVP_PKEY_CTX should be	assigned to the
       EVP_MD_CTX. This	is done	by calling:

	EVP_MD_CTX_set_pkey_ctx(mctx, pctx);

       And normally there is no	need to	pass a pctx parameter to
       EVP_DigestSignInit() or EVP_DigestVerifyInit() in such a	scenario.

       This example demonstrates the calling sequence for using	an EVP_PKEY to
       verify a	message	with the SM2 signature algorithm and the SM3 hash

	#include <openssl/evp.h>

	/* obtain an EVP_PKEY using whatever methods...	*/
	EVP_PKEY_set_alias_type(pkey, EVP_PKEY_SM2);
	mctx = EVP_MD_CTX_new();
	pctx = EVP_PKEY_CTX_new(pkey, NULL);
	EVP_PKEY_CTX_set1_id(pctx, id, id_len);
	EVP_MD_CTX_set_pkey_ctx(mctx, pctx);;
	EVP_DigestVerifyInit(mctx, NULL, EVP_sm3(), NULL, pkey);
	EVP_DigestVerifyUpdate(mctx, msg, msg_len);
	EVP_DigestVerifyFinal(mctx, sig, sig_len)

       EVP_PKEY_CTX_new(3), EVP_PKEY_set_alias_type(3),	EVP_DigestSignInit(3),
       EVP_DigestVerifyInit(3),	EVP_PKEY_CTX_set1_id(3),

       Copyright 2018-2020 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

1.1.1h				  2020-09-22				SM2(7)


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