85 lines
2.3 KiB
Plaintext
85 lines
2.3 KiB
Plaintext
=pod
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=head1 NAME
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RSA_public_encrypt, RSA_private_decrypt - RSA public key cryptography
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=head1 SYNOPSIS
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#include <openssl/rsa.h>
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int RSA_public_encrypt(int flen, unsigned char *from,
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unsigned char *to, RSA *rsa, int padding);
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int RSA_private_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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RSA_public_encrypt() encrypts the B<flen> bytes at B<from> (usually a
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session key) using the public key B<rsa> and stores the ciphertext in
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B<to>. B<to> must point to RSA_size(B<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 currently is the most widely used mode.
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=item RSA_PKCS1_OAEP_PADDING
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EME-OAEP as defined in PKCS #1 v2.0 with SHA-1, MGF1 and an empty
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encoding parameter. This mode is recommended for all new applications.
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=item RSA_SSLV23_PADDING
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PKCS #1 v1.5 padding with an SSL-specific modification that denotes
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that the server is SSL3 capable.
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=item RSA_NO_PADDING
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Raw RSA encryption. 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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Encrypting user data directly with RSA is insecure.
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=back
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B<flen> must be less than RSA_size(B<rsa>) - 11 for the PKCS #1 v1.5
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based padding modes, less than RSA_size(B<rsa>) - 41 for
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RSA_PKCS1_OAEP_PADDING and exactly RSA_size(B<rsa>) for RSA_NO_PADDING.
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The random number generator must be seeded prior to calling
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RSA_public_encrypt().
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RSA_private_decrypt() decrypts the B<flen> bytes at B<from> using the
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private key B<rsa> and stores the plaintext in B<to>. B<to> must point
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to a memory section large enough to hold the decrypted data (which is
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smaller than RSA_size(B<rsa>)). B<padding> is the padding mode that
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was used to encrypt the data.
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=head1 RETURN VALUES
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RSA_public_encrypt() returns the size of the encrypted data (i.e.,
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RSA_size(B<rsa>)). RSA_private_decrypt() returns the size of the
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recovered plaintext.
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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)|ERR_get_error(3)>.
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=head1 CONFORMING TO
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SSL, PKCS #1 v2.0
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=head1 SEE ALSO
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L<ERR_get_error(3)|ERR_get_error(3)>, L<rand(3)|rand(3)>, L<rsa(3)|rsa(3)>,
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L<RSA_size(3)|RSA_size(3)>
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=head1 HISTORY
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The B<padding> argument was added in SSLeay 0.8. RSA_NO_PADDING is
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available since SSLeay 0.9.0, OAEP was added in OpenSSL 0.9.2b.
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=cut
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