| Index: openssl/doc/crypto/EVP_PKEY_verify.pod
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| ===================================================================
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| --- openssl/doc/crypto/EVP_PKEY_verify.pod	(revision 0)
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| +++ openssl/doc/crypto/EVP_PKEY_verify.pod	(revision 0)
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| @@ -0,0 +1,91 @@
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| +=pod
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| +
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| +=head1 NAME
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| +
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| +EVP_PKEY_verify_init, EVP_PKEY_verify - signature verification using a public key algorithm
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| +
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| +=head1 SYNOPSIS
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| +
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| + #include <openssl/evp.h>
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| +
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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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| +
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| +=head1 DESCRIPTION
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| +
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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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| +
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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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| +
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| +=head1 NOTES
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| +
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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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| +
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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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| +
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| +=head1 RETURN VALUES
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| +
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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 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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| +
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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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| +
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| +=head1 EXAMPLE
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| +
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| +Verify signature using PKCS#1 and SHA256 digest:
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| +
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| + #include <openssl/evp.h>
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| + #include <openssl/rsa.h>
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| +
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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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| + /* 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);
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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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| +
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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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| +
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| +=head1 SEE ALSO
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| +
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| +L<EVP_PKEY_CTX_new(3)|EVP_PKEY_CTX_new(3)>,
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| +L<EVP_PKEY_encrypt(3)|EVP_PKEY_encrypt(3)>,
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| +L<EVP_PKEY_decrypt(3)|EVP_PKEY_decrypt(3)>,
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| +L<EVP_PKEY_sign(3)|EVP_PKEY_sign(3)>,
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| +L<EVP_PKEY_verifyrecover(3)|EVP_PKEY_verifyrecover(3)>,
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| +L<EVP_PKEY_derive(3)|EVP_PKEY_derive(3)> 
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| +
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| +=head1 HISTORY
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| +
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| +These functions were first added to OpenSSL 1.0.0.
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| +
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| +=cut
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| 
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