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@@ -6,23 +6,25 @@ SM2 - Chinese SM2 signature and encryption algorithm support
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=head1 DESCRIPTION
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-B<SM2> algorithm is first defined by the Chinese national standard GM/T 0003-2012
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-and is standardized by ISO as ISO/IEC 14888. B<SM2> is actually an elliptic curve
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-based algorithm. Currnet implementation in OpenSSL supports both signature and
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-encryption schemes via EVP interface.
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+The B<SM2> algorithm was first defined by the Chinese national standard GM/T
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+0003-2012 and was later standardized by ISO as ISO/IEC 14888. B<SM2> is actually
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+an elliptic curve based algorithm. The current implementation in OpenSSL supports
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+both signature and encryption schemes via the EVP interface.
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When doing the B<SM2> signature algorithm, it requires a distinguishing identifier
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to form the message prefix which is hashed before the real message is hashed.
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=head1 NOTES
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-B<SM2> signature can be generated by using the 'DigestSign' series APIs, for instance,
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-EVP_DigestSignInit(), EVP_DigestSignUpdate() and EVP_DigestSignFinal(). Ditto
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-for the verification process by calling the 'DigestVerify' series APIs.
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+B<SM2> signatures can be generated by using the 'DigestSign' series of APIs, for
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+instance, EVP_DigestSignInit(), EVP_DigestSignUpdate() and EVP_DigestSignFinal().
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+Ditto for the verification process by calling the 'DigestVerify' series of APIs.
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-There are several special steps need to be done before computing an B<SM2> signature.
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+There are several special steps that need to be done before computing an B<SM2>
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+signature.
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-The B<EVP_PKEY> structure should be set to B<EVP_PKEY_SM2> by calling:
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+The B<EVP_PKEY> structure will default to using ECDSA for signatures when it is
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+created. It should be set to B<EVP_PKEY_SM2> by calling:
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EVP_PKEY_set_alias_type(pkey, EVP_PKEY_SM2);
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@@ -30,23 +32,23 @@ Then an ID should be set by calling:
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EVP_PKEY_CTX_set1_id(pctx, id, id_len);
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-When calling the EVP_DeigestSignInit() or EVP_DigestVerifyInit() function, a
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+When calling the EVP_DigestSignInit() or EVP_DigestVerifyInit() functions, a
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pre-allocated B<EVP_PKEY_CTX> should be assigned to the B<EVP_MD_CTX>. This is
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done by calling:
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EVP_MD_CTX_set_pkey_ctx(mctx, pctx);
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-And normally there is no need to pass a B<pctx> parameter to EVP_DeigestSignInit()
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-or EVP_DigestVerifyInit() in such scenario.
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+And normally there is no need to pass a B<pctx> parameter to EVP_DigestSignInit()
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+or EVP_DigestVerifyInit() in such a scenario.
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=head1 EXAMPLE
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-This example demonstrates the calling sequence on how to use an B<EVP_PKEY> to
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-sign a message with SM2 signature algorithm and SM3 hash algorithm:
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+This example demonstrates the calling sequence for using an B<EVP_PKEY> to verify
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+a message with the SM2 signature algorithm and the SM3 hash algorithm:
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#include <openssl/evp.h>
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- /* obtain an EVP_PKEY from whatever methods... */
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+ /* obtain an EVP_PKEY using whatever methods... */
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EVP_PKEY_set_alias_type(pkey, EVP_PKEY_SM2);
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mctx = EVP_MD_CTX_new();
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pctx = EVP_PKEY_CTX_new(pkey, NULL);
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