Switch from OpenSSL 0.9.7d to 0.9.7e.
[dragonfly.git] / secure / lib / libcrypto / man / EVP_VerifyInit.3
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80.\" If the F register is turned on, we'll generate
81.\" index entries out stderr for the following things:
82.\" TH Title
83.\" SH Header
84.\" Sh Subsection
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96.TH EVP_VerifyInit 3 "0.9.7d" "2/Sep/2004" "OpenSSL"
97.UC
98.if n .hy 0
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188.\}
189.rm #[ #] #H #V #F C
984263bc 190.SH "NAME"
74dab6c2 191EVP_VerifyInit, EVP_VerifyUpdate, EVP_VerifyFinal \- EVP signature verification functions
984263bc 192.SH "SYNOPSIS"
74dab6c2 193.PP
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194.Vb 1
195\& #include <openssl/evp.h>
196.Ve
197.Vb 3
198\& int EVP_VerifyInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl);
199\& int EVP_VerifyUpdate(EVP_MD_CTX *ctx, const void *d, unsigned int cnt);
200\& int EVP_VerifyFinal(EVP_MD_CTX *ctx,unsigned char *sigbuf, unsigned int siglen,EVP_PKEY *pkey);
201.Ve
202.Vb 1
203\& int EVP_VerifyInit(EVP_MD_CTX *ctx, const EVP_MD *type);
204.Ve
205.SH "DESCRIPTION"
74dab6c2 206The EVP signature verification routines are a high level interface to digital
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207signatures.
208.PP
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209\fIEVP_VerifyInit_ex()\fR sets up verification context \fBctx\fR to use digest
210\fBtype\fR from ENGINE \fBimpl\fR. \fBctx\fR must be initialized by calling
211\fIEVP_MD_CTX_init()\fR before calling this function.
984263bc 212.PP
74dab6c2 213\fIEVP_VerifyUpdate()\fR hashes \fBcnt\fR bytes of data at \fBd\fR into the
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214verification context \fBctx\fR. This function can be called several times on the
215same \fBctx\fR to include additional data.
216.PP
74dab6c2 217\fIEVP_VerifyFinal()\fR verifies the data in \fBctx\fR using the public key \fBpkey\fR
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218and against the \fBsiglen\fR bytes at \fBsigbuf\fR.
219.PP
74dab6c2 220\fIEVP_VerifyInit()\fR initializes verification context \fBctx\fR to use the default
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221implementation of digest \fBtype\fR.
222.SH "RETURN VALUES"
74dab6c2 223\fIEVP_VerifyInit_ex()\fR and \fIEVP_VerifyUpdate()\fR return 1 for success and 0 for
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224failure.
225.PP
74dab6c2 226\fIEVP_VerifyFinal()\fR returns 1 for a correct signature, 0 for failure and \-1 if some
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227other error occurred.
228.PP
229The error codes can be obtained by ERR_get_error(3).
230.SH "NOTES"
74dab6c2 231The \fBEVP\fR interface to digital signatures should almost always be used in
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232preference to the low level interfaces. This is because the code then becomes
233transparent to the algorithm used and much more flexible.
234.PP
235Due to the link between message digests and public key algorithms the correct
236digest algorithm must be used with the correct public key type. A list of
237algorithms and associated public key algorithms appears in
238EVP_DigestInit(3).
239.PP
240The call to \fIEVP_VerifyFinal()\fR internally finalizes a copy of the digest context.
241This means that calls to \fIEVP_VerifyUpdate()\fR and \fIEVP_VerifyFinal()\fR can be called
242later to digest and verify additional data.
243.PP
244Since only a copy of the digest context is ever finalized the context must
245be cleaned up after use by calling \fIEVP_MD_CTX_cleanup()\fR or a memory leak
246will occur.
247.SH "BUGS"
984263bc 248Older versions of this documentation wrongly stated that calls to
74dab6c2 249\fIEVP_VerifyUpdate()\fR could not be made after calling \fIEVP_VerifyFinal()\fR.
984263bc 250.SH "SEE ALSO"
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251evp(3),
252EVP_SignInit(3),
253EVP_DigestInit(3), err(3),
254evp(3), hmac(3), md2(3),
255md5(3), mdc2(3), ripemd(3),
256sha(3), dgst(1)
257.SH "HISTORY"
74dab6c2 258\fIEVP_VerifyInit()\fR, \fIEVP_VerifyUpdate()\fR and \fIEVP_VerifyFinal()\fR are
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259available in all versions of SSLeay and OpenSSL.
260.PP
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261\fIEVP_VerifyInit_ex()\fR was added in OpenSSL 0.9.7
262
263.rn }` ''
264.IX Title "EVP_VerifyInit 3"
265.IX Name "EVP_VerifyInit, EVP_VerifyUpdate, EVP_VerifyFinal - EVP signature verification functions"
266
267.IX Header "NAME"
268
269.IX Header "SYNOPSIS"
270
271.IX Header "DESCRIPTION"
272
273.IX Header "RETURN VALUES"
274
275.IX Header "NOTES"
276
277.IX Header "BUGS"
278
279.IX Header "SEE ALSO"
280
281.IX Header "HISTORY"
282