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			88 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
			
		
		
	
	
			88 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
=pod
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=head1 NAME
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RSA_private_encrypt, RSA_public_decrypt - low-level signature operations
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=head1 SYNOPSIS
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 #include <openssl/rsa.h>
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Deprecated since OpenSSL 3.0, can be hidden entirely by defining
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B<OPENSSL_API_COMPAT> with a suitable version value, see
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L<openssl_user_macros(7)>:
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 int RSA_private_encrypt(int flen, unsigned char *from,
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                         unsigned char *to, RSA *rsa, int padding);
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 int RSA_public_decrypt(int flen, unsigned char *from,
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                        unsigned char *to, RSA *rsa, int padding);
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=head1 DESCRIPTION
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Both of the functions described on this page are deprecated.
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Applications should instead use L<EVP_PKEY_encrypt_init_ex(3)>,
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L<EVP_PKEY_encrypt(3)>, L<EVP_PKEY_decrypt_init_ex(3)> and
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L<EVP_PKEY_decrypt(3)>.
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These functions handle RSA signatures at a low-level.
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RSA_private_encrypt() signs the B<flen> bytes at B<from> (usually a
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message digest with an algorithm identifier) using the private key
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B<rsa> and stores the signature in B<to>. B<to> must point to
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B<RSA_size(rsa)> bytes of memory.
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B<padding> denotes one of the following modes:
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=over 4
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=item RSA_PKCS1_PADDING
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PKCS #1 v1.5 padding. This function does not handle the
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B<algorithmIdentifier> specified in PKCS #1. When generating or
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verifying PKCS #1 signatures, L<RSA_sign(3)> and L<RSA_verify(3)> should be
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used.
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=item RSA_NO_PADDING
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Raw RSA signature. This mode should I<only> be used to implement
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cryptographically sound padding modes in the application code.
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Signing user data directly with RSA is insecure.
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=back
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RSA_public_decrypt() recovers the message digest from the B<flen>
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bytes long signature at B<from> using the signer's public key
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B<rsa>. B<to> must point to a memory section large enough to hold the
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message digest (which is smaller than B<RSA_size(rsa) -
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11>). B<padding> is the padding mode that was used to sign the data.
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=head1 RETURN VALUES
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RSA_private_encrypt() returns the size of the signature (i.e.,
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RSA_size(rsa)). RSA_public_decrypt() returns the size of the
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recovered message digest.
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On error, -1 is returned; the error codes can be
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obtained by L<ERR_get_error(3)>.
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=head1 SEE ALSO
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L<ERR_get_error(3)>,
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L<RSA_sign(3)>, L<RSA_verify(3)>
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=head1 HISTORY
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Both of these functions were deprecated in OpenSSL 3.0.
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=head1 COPYRIGHT
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Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
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Licensed under the Apache License 2.0 (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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