1=pod 2 3=head1 NAME 4 5RSA_public_encrypt, RSA_private_decrypt - RSA public key cryptography 6 7=head1 SYNOPSIS 8 9 #include <openssl/rsa.h> 10 11 int RSA_public_encrypt(int flen, unsigned char *from, 12 unsigned char *to, RSA *rsa, int padding); 13 14 int RSA_private_decrypt(int flen, unsigned char *from, 15 unsigned char *to, RSA *rsa, int padding); 16 17=head1 DESCRIPTION 18 19RSA_public_encrypt() encrypts the B<flen> bytes at B<from> (usually a 20session key) using the public key B<rsa> and stores the ciphertext in 21B<to>. B<to> must point to RSA_size(B<rsa>) bytes of memory. 22 23B<padding> denotes one of the following modes: 24 25=over 4 26 27=item RSA_PKCS1_PADDING 28 29PKCS #1 v1.5 padding. This currently is the most widely used mode. 30 31=item RSA_PKCS1_OAEP_PADDING 32 33EME-OAEP as defined in PKCS #1 v2.0 with SHA-1, MGF1 and an empty 34encoding parameter. This mode is recommended for all new applications. 35 36=item RSA_SSLV23_PADDING 37 38PKCS #1 v1.5 padding with an SSL-specific modification that denotes 39that the server is SSL3 capable. 40 41=item RSA_NO_PADDING 42 43Raw RSA encryption. This mode should I<only> be used to implement 44cryptographically sound padding modes in the application code. 45Encrypting user data directly with RSA is insecure. 46 47=back 48 49B<flen> must be less than RSA_size(B<rsa>) - 11 for the PKCS #1 v1.5 50based padding modes, less than RSA_size(B<rsa>) - 41 for 51RSA_PKCS1_OAEP_PADDING and exactly RSA_size(B<rsa>) for RSA_NO_PADDING. 52The random number generator must be seeded prior to calling 53RSA_public_encrypt(). 54 55RSA_private_decrypt() decrypts the B<flen> bytes at B<from> using the 56private key B<rsa> and stores the plaintext in B<to>. B<to> must point 57to a memory section large enough to hold the decrypted data (which is 58smaller than RSA_size(B<rsa>)). B<padding> is the padding mode that 59was used to encrypt the data. 60 61=head1 RETURN VALUES 62 63RSA_public_encrypt() returns the size of the encrypted data (i.e., 64RSA_size(B<rsa>)). RSA_private_decrypt() returns the size of the 65recovered plaintext. 66 67On error, -1 is returned; the error codes can be 68obtained by L<ERR_get_error(3)|ERR_get_error(3)>. 69 70=head1 CONFORMING TO 71 72SSL, PKCS #1 v2.0 73 74=head1 SEE ALSO 75 76L<ERR_get_error(3)|ERR_get_error(3)>, L<rand(3)|rand(3)>, L<rsa(3)|rsa(3)>, 77L<RSA_size(3)|RSA_size(3)> 78 79=head1 HISTORY 80 81The B<padding> argument was added in SSLeay 0.8. RSA_NO_PADDING is 82available since SSLeay 0.9.0, OAEP was added in OpenSSL 0.9.2b. 83 84=cut 85