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Diffstat (limited to 'secure/lib/libcrypto/man/EVP_DigestVerifyInit.3')
| -rw-r--r-- | secure/lib/libcrypto/man/EVP_DigestVerifyInit.3 | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/secure/lib/libcrypto/man/EVP_DigestVerifyInit.3 b/secure/lib/libcrypto/man/EVP_DigestVerifyInit.3 new file mode 100644 index 0000000..af521a6 --- /dev/null +++ b/secure/lib/libcrypto/man/EVP_DigestVerifyInit.3 @@ -0,0 +1,204 @@ +.\" Automatically generated by Pod::Man 2.23 (Pod::Simple 3.22) +.\" +.\" Standard preamble: +.\" ======================================================================== +.de Sp \" Vertical space (when we can't use .PP) +.if t .sp .5v +.if n .sp +.. +.de Vb \" Begin verbatim text +.ft CW +.nf +.ne \\$1 +.. +.de Ve \" End verbatim text +.ft R +.fi +.. +.\" Set up some character translations and predefined strings. \*(-- will +.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left +.\" double quote, and \*(R" will give a right double quote. \*(C+ will +.\" give a nicer C++. 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Always turn off hyphenation; it makes +.\" way too many mistakes in technical documents. +.if n .ad l +.nh +.SH "NAME" +EVP_DigestVerifyInit, EVP_DigestVerifyUpdate, EVP_DigestVerifyFinal \- EVP signature verification functions +.SH "SYNOPSIS" +.IX Header "SYNOPSIS" +.Vb 1 +\& #include <openssl/evp.h> +\& +\& int EVP_DigestVerifyInit(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx, +\& const EVP_MD *type, ENGINE *e, EVP_PKEY *pkey); +\& int EVP_DigestVerifyUpdate(EVP_MD_CTX *ctx, const void *d, unsigned int cnt); +\& int EVP_DigestVerifyFinal(EVP_MD_CTX *ctx, unsigned char *sig, size_t siglen); +.Ve +.SH "DESCRIPTION" +.IX Header "DESCRIPTION" +The \s-1EVP\s0 signature routines are a high level interface to digital signatures. +.PP +\&\fIEVP_DigestVerifyInit()\fR sets up verification context \fBctx\fR to use digest +\&\fBtype\fR from \s-1ENGINE\s0 \fBimpl\fR and public key \fBpkey\fR. \fBctx\fR must be initialized +with \fIEVP_MD_CTX_init()\fR before calling this function. If \fBpctx\fR is not \s-1NULL\s0 the +\&\s-1EVP_PKEY_CTX\s0 of the verification operation will be written to \fB*pctx\fR: this +can be used to set alternative verification options. +.PP +\&\fIEVP_DigestVerifyUpdate()\fR hashes \fBcnt\fR bytes of data at \fBd\fR into the +verification context \fBctx\fR. This function can be called several times on the +same \fBctx\fR to include additional data. This function is currently implemented +using a macro. +.PP +\&\fIEVP_DigestVerifyFinal()\fR verifies the data in \fBctx\fR against the signature in +\&\fBsig\fR of length \fBsiglen\fR. +.SH "RETURN VALUES" +.IX Header "RETURN VALUES" +\&\fIEVP_DigestVerifyInit()\fR and \fIEVP_DigestVerifyUpdate()\fR return 1 for success and 0 +or a negative value for failure. In particular a return value of \-2 indicates +the operation is not supported by the public key algorithm. +.PP +Unlike other functions the return value 0 from \fIEVP_DigestVerifyFinal()\fR only +indicates that the signature did not not verify successfully (that is tbs did +not match the original data or the signature was of invalid form) it is not an +indication of a more serious error. +.PP +The error codes can be obtained from \fIERR_get_error\fR\|(3). +.SH "NOTES" +.IX Header "NOTES" +The \fB\s-1EVP\s0\fR interface to digital signatures should almost always be used in +preference to the low level interfaces. This is because the code then becomes +transparent to the algorithm used and much more flexible. +.PP +In previous versions of OpenSSL there was a link between message digest types +and public key algorithms. This meant that \*(L"clone\*(R" digests such as \fIEVP_dss1()\fR +needed to be used to sign using \s-1SHA1\s0 and \s-1DSA\s0. This is no longer necessary and +the use of clone digest is now discouraged. +.PP +For some key types and parameters the random number generator must be seeded +or the operation will fail. +.PP +The call to \fIEVP_DigestVerifyFinal()\fR internally finalizes a copy of the digest +context. This means that calls to \fIEVP_VerifyUpdate()\fR and \fIEVP_VerifyFinal()\fR can +be called later to digest and verify additional data. +.PP +Since only a copy of the digest context is ever finalized the context must +be cleaned up after use by calling \fIEVP_MD_CTX_cleanup()\fR or a memory leak +will occur. +.SH "SEE ALSO" +.IX Header "SEE ALSO" +\&\fIEVP_DigestSignInit\fR\|(3), +\&\fIEVP_DigestInit\fR\|(3), \fIerr\fR\|(3), +\&\fIevp\fR\|(3), \fIhmac\fR\|(3), \fImd2\fR\|(3), +\&\fImd5\fR\|(3), \fImdc2\fR\|(3), \fIripemd\fR\|(3), +\&\fIsha\fR\|(3), \fIdgst\fR\|(1) +.SH "HISTORY" +.IX Header "HISTORY" +\&\fIEVP_DigestVerifyInit()\fR, \fIEVP_DigestVerifyUpdate()\fR and \fIEVP_DigestVerifyFinal()\fR +were first added to OpenSSL 1.0.0. |
