Automatically generated by Pod::Man 4.14 (Pod::Simple 3.40)

Standard preamble:
========================================================================
..

..

.. 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++. Capital omega is used to do unbreakable dashes and
therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
nothing in troff, for use with C<>.
.tr \(*W- . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\}
Escape single quotes in literal strings from groff's Unicode transform.

If the F register is >0, we'll generate index entries on stderr for
titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
entries marked with X<> in POD. Of course, you'll have to process the
output yourself in some meaningful fashion.

Avoid warning from groff about undefined register 'F'.
.. .nr rF 0 . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF
Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
Fear. Run. Save yourself. No user-serviceable parts.
. \" fudge factors for nroff and troff . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] .\} . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents . \" corrections for vroff . \" for low resolution devices (crt and lpr) \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} ========================================================================

Title "EVP_VERIFYINIT 3" For nroff, turn off justification. Always turn off hyphenation; it makes
way too many mistakes in technical documents.
EVP_VerifyInit_ex, EVP_VerifyInit, EVP_VerifyUpdate, EVP_VerifyFinal \- EVP signature verification functions Header "SYNOPSIS" .Vb 1 #include <openssl/evp.h> \& int EVP_VerifyInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl); int EVP_VerifyUpdate(EVP_MD_CTX *ctx, const void *d, unsigned int cnt); int EVP_VerifyFinal(EVP_MD_CTX *ctx, unsigned char *sigbuf, unsigned int siglen, EVP_PKEY *pkey); \& int EVP_VerifyInit(EVP_MD_CTX *ctx, const EVP_MD *type); .Ve Header "DESCRIPTION" The \s-1EVP\s0 signature verification routines are a high-level interface to digital signatures.

\fBEVP_VerifyInit_ex() sets up verification context ctx to use digest \fBtype from \s-1ENGINE\s0 impl. ctx must be created by calling \fBEVP_MD_CTX_new() before calling this function.

\fBEVP_VerifyUpdate() hashes cnt bytes of data at d into the verification context ctx. This function can be called several times on the same ctx to include additional data.

\fBEVP_VerifyFinal() verifies the data in ctx using the public key pkey and against the siglen bytes at sigbuf.

\fBEVP_VerifyInit() initializes verification context ctx to use the default implementation of digest type.

Header "RETURN VALUES" \fBEVP_VerifyInit_ex() and EVP_VerifyUpdate() return 1 for success and 0 for failure.

\fBEVP_VerifyFinal() returns 1 for a correct signature, 0 for failure and -1 if some other error occurred.

The error codes can be obtained by ERR_get_error\|(3).

Header "NOTES" The \s-1EVP\s0 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.

The call to EVP_VerifyFinal() internally finalizes a copy of the digest context. This means that calls to EVP_VerifyUpdate() and EVP_VerifyFinal() can be called later to digest and verify additional data.

Since only a copy of the digest context is ever finalized the context must be cleaned up after use by calling EVP_MD_CTX_free() or a memory leak will occur.

Header "BUGS" Older versions of this documentation wrongly stated that calls to \fBEVP_VerifyUpdate() could not be made after calling EVP_VerifyFinal().

Since the public key is passed in the call to EVP_SignFinal() any error relating to the private key (for example an unsuitable key and digest combination) will not be indicated until after potentially large amounts of data have been passed through EVP_SignUpdate().

It is not possible to change the signing parameters using these function.

The previous two bugs are fixed in the newer EVP_DigestVerify*() function.

Header "SEE ALSO" \fBevp\|(7), \fBEVP_SignInit\|(3), \fBEVP_DigestInit\|(3), \fBevp\|(7), \s-1HMAC\s0\|(3), \s-1MD2\s0\|(3), \s-1MD5\s0\|(3), \s-1MDC2\s0\|(3), \s-1RIPEMD160\s0\|(3), \s-1SHA1\s0\|(3), dgst\|(1) Header "COPYRIGHT" Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (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>.