Android_verify/third_party/android-libs/share/man/man7/EVP_PKEY-SM2.7ossl

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.\" ========================================================================
.\"
.IX Title "EVP_PKEY-SM2 7ossl"
.TH EVP_PKEY-SM2 7ossl "2024-09-03" "3.3.2" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.if n .ad l
.nh
.SH "NAME"
EVP_PKEY\-SM2, EVP_KEYMGMT\-SM2, SM2
\&\- EVP_PKEY keytype support for the Chinese SM2 signature and encryption algorithms
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The \fB\s-1SM2\s0\fR algorithm was first defined by the Chinese national standard \s-1GM/T
0003\-2012\s0 and was later standardized by \s-1ISO\s0 as \s-1ISO/IEC 14888.\s0 \fB\s-1SM2\s0\fR is actually
an elliptic curve based algorithm. The current implementation in OpenSSL supports
both signature and encryption schemes via the \s-1EVP\s0 interface.
.PP
When doing the \fB\s-1SM2\s0\fR signature algorithm, it requires a distinguishing identifier
to form the message prefix which is hashed before the real message is hashed.
.SS "Common \s-1SM2\s0 parameters"
.IX Subsection "Common SM2 parameters"
\&\s-1SM2\s0 uses the parameters defined in \*(L"Common \s-1EC\s0 parameters\*(R" in \s-1\fBEVP_PKEY\-EC\s0\fR\|(7).
The following parameters are different:
.ie n .IP """cofactor"" (\fB\s-1OSSL_PKEY_PARAM_EC_COFACTOR\s0\fR) <unsigned integer>" 4
.el .IP "``cofactor'' (\fB\s-1OSSL_PKEY_PARAM_EC_COFACTOR\s0\fR) <unsigned integer>" 4
.IX Item "cofactor (OSSL_PKEY_PARAM_EC_COFACTOR) <unsigned integer>"
This parameter is ignored for \fB\s-1SM2\s0\fR.
.IP "(\fB\s-1OSSL_PKEY_PARAM_DEFAULT_DIGEST\s0\fR) <\s-1UTF8\s0 string>" 4
.IX Item "(OSSL_PKEY_PARAM_DEFAULT_DIGEST) <UTF8 string>"
Getter that returns the default digest name.
(Currently returns \*(L"\s-1SM3\*(R"\s0 as of OpenSSL 3.0).
.SH "NOTES"
.IX Header "NOTES"
\&\fB\s-1SM2\s0\fR signatures can be generated by using the 'DigestSign' series of APIs, for
instance, \fBEVP_DigestSignInit()\fR, \fBEVP_DigestSignUpdate()\fR and \fBEVP_DigestSignFinal()\fR.
Ditto for the verification process by calling the 'DigestVerify' series of APIs.
Note that the \s-1SM2\s0 algorithm requires the presence of the public key for signatures,
as such the \fB\s-1OSSL_PKEY_PARAM_PUB_KEY\s0\fR option must be set on any key used in signature
generation.
.PP
Before computing an \fB\s-1SM2\s0\fR signature, an \fB\s-1EVP_PKEY_CTX\s0\fR needs to be created,
and an \fB\s-1SM2\s0\fR \s-1ID\s0 must be set for it, like this:
.PP
.Vb 1
\& EVP_PKEY_CTX_set1_id(pctx, id, id_len);
.Ve
.PP
Before calling the \fBEVP_DigestSignInit()\fR or \fBEVP_DigestVerifyInit()\fR functions,
that \fB\s-1EVP_PKEY_CTX\s0\fR should be assigned to the \fB\s-1EVP_MD_CTX\s0\fR, like this:
.PP
.Vb 1
\& EVP_MD_CTX_set_pkey_ctx(mctx, pctx);
.Ve
.PP
There is normally no need to pass a \fBpctx\fR parameter to \fBEVP_DigestSignInit()\fR
or \fBEVP_DigestVerifyInit()\fR in such a scenario.
.PP
\&\s-1SM2\s0 can be tested with the \fBopenssl\-speed\fR\|(1) application since version 3.0.
Currently, the only valid algorithm name is \fBsm2\fR.
.PP
Since version 3.0, \s-1SM2\s0 keys can be generated and loaded only when the domain
parameters specify the \s-1SM2\s0 elliptic curve.
.SH "EXAMPLES"
.IX Header "EXAMPLES"
This example demonstrates the calling sequence for using an \fB\s-1EVP_PKEY\s0\fR to verify
a message with the \s-1SM2\s0 signature algorithm and the \s-1SM3\s0 hash algorithm:
.PP
.Vb 1
\& #include <openssl/evp.h>
\&
\& /* obtain an EVP_PKEY using whatever methods... */
\& 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)
.Ve
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBEVP_PKEY_CTX_new\fR\|(3),
\&\fBEVP_DigestSignInit\fR\|(3),
\&\fBEVP_DigestVerifyInit\fR\|(3),
\&\fBEVP_PKEY_CTX_set1_id\fR\|(3),
\&\fBEVP_MD_CTX_set_pkey_ctx\fR\|(3)
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2018\-2024 The OpenSSL Project Authors. All Rights Reserved.
.PP
Licensed under the Apache License 2.0 (the \*(L"License\*(R").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file \s-1LICENSE\s0 in the source distribution or at
<https://www.openssl.org/source/license.html>.