a528d4f0a9
If something was "present in all versions" of SSLeay, or if it was added to a version of SSLeay (and therefore predates OpenSSL), remove mention of it. Documentation history now starts with OpenSSL. Remove mention of all history before OpenSSL 0.9.8, inclusive. Remove all AUTHOR sections. Reviewed-by: Tim Hudson <tjh@openssl.org>
65 lines
1.8 KiB
Text
65 lines
1.8 KiB
Text
=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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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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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)>, L<rsa(3)>,
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L<RSA_sign(3)>, L<RSA_verify(3)>
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=cut
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