df75c2bfcd
While stereotyped repetitions are frowned upon in literature, they serve a useful purpose in manual pages, because it is easier for the user to find certain information if it is always presented in the same way. For that reason, this commit harmonizes the varying formulations in the HISTORY section about which functions, flags, etc. were added in which OpenSSL version. It also attempts to make the pod files more grep friendly by avoiding to insert line breaks between the symbol names and the corresponding version number in which they were introduced (wherever possible). Some punctuation and typographical errors were fixed on the way. Reviewed-by: Tim Hudson <tjh@openssl.org> (Merged from https://github.com/openssl/openssl/pull/7854)
103 lines
3 KiB
Text
103 lines
3 KiB
Text
=pod
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=head1 NAME
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EVP_PKEY_verify_init, EVP_PKEY_verify - signature verification using a public key algorithm
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=head1 SYNOPSIS
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#include <openssl/evp.h>
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int EVP_PKEY_verify_init(EVP_PKEY_CTX *ctx);
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int EVP_PKEY_verify(EVP_PKEY_CTX *ctx,
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const unsigned char *sig, size_t siglen,
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const unsigned char *tbs, size_t tbslen);
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=head1 DESCRIPTION
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The EVP_PKEY_verify_init() function initializes a public key algorithm
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context using key B<pkey> for a signature verification operation.
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The EVP_PKEY_verify() function performs a public key verification operation
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using B<ctx>. The signature is specified using the B<sig> and
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B<siglen> parameters. The verified data (i.e. the data believed originally
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signed) is specified using the B<tbs> and B<tbslen> parameters.
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=head1 NOTES
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After the call to EVP_PKEY_verify_init() algorithm specific control
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operations can be performed to set any appropriate parameters for the
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operation.
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The function EVP_PKEY_verify() can be called more than once on the same
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context if several operations are performed using the same parameters.
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=head1 RETURN VALUES
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EVP_PKEY_verify_init() and EVP_PKEY_verify() return 1 if the verification was
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successful and 0 if it failed. Unlike other functions the return value 0 from
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EVP_PKEY_verify() only indicates that the signature did not verify
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successfully (that is tbs did not match the original data or the signature was
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of invalid form) it is not an indication of a more serious error.
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A negative value indicates an error other that signature verification failure.
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In particular a return value of -2 indicates the operation is not supported by
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the public key algorithm.
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=head1 EXAMPLE
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Verify signature using PKCS#1 and SHA256 digest:
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#include <openssl/evp.h>
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#include <openssl/rsa.h>
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EVP_PKEY_CTX *ctx;
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unsigned char *md, *sig;
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size_t mdlen, siglen;
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EVP_PKEY *verify_key;
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/*
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* NB: assumes verify_key, sig, siglen md and mdlen are already set up
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* and that verify_key is an RSA public key
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*/
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ctx = EVP_PKEY_CTX_new(verify_key, NULL /* no engine */);
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if (!ctx)
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/* Error occurred */
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if (EVP_PKEY_verify_init(ctx) <= 0)
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/* Error */
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if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PADDING) <= 0)
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/* Error */
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if (EVP_PKEY_CTX_set_signature_md(ctx, EVP_sha256()) <= 0)
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/* Error */
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/* Perform operation */
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ret = EVP_PKEY_verify(ctx, sig, siglen, md, mdlen);
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/*
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* ret == 1 indicates success, 0 verify failure and < 0 for some
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* other error.
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*/
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=head1 SEE ALSO
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L<EVP_PKEY_CTX_new(3)>,
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L<EVP_PKEY_encrypt(3)>,
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L<EVP_PKEY_decrypt(3)>,
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L<EVP_PKEY_sign(3)>,
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L<EVP_PKEY_verify_recover(3)>,
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L<EVP_PKEY_derive(3)>
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=head1 HISTORY
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These functions were added in OpenSSL 1.0.0.
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=head1 COPYRIGHT
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Copyright 2006-2018 The OpenSSL Project Authors. All Rights Reserved.
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Licensed under the OpenSSL license (the "License"). You may not use
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this file except in compliance with the License. You can obtain a copy
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in the file LICENSE in the source distribution or at
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L<https://www.openssl.org/source/license.html>.
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=cut
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