| =pod |
| |
| =head1 NAME |
| |
| RSA_public_encrypt, RSA_private_decrypt - RSA public key cryptography |
| |
| =head1 SYNOPSIS |
| |
| #include <openssl/rsa.h> |
| |
| int RSA_public_encrypt(int flen, unsigned char *from, |
| unsigned char *to, RSA *rsa, int padding); |
| |
| int RSA_private_decrypt(int flen, unsigned char *from, |
| unsigned char *to, RSA *rsa, int padding); |
| |
| =head1 DESCRIPTION |
| |
| RSA_public_encrypt() encrypts the B<flen> bytes at B<from> (usually a |
| session key) using the public key B<rsa> and stores the ciphertext in |
| B<to>. B<to> must point to RSA_size(B<rsa>) bytes of memory. |
| |
| B<padding> denotes one of the following modes: |
| |
| =over 4 |
| |
| =item RSA_PKCS1_PADDING |
| |
| PKCS #1 v1.5 padding. This currently is the most widely used mode. |
| |
| =item RSA_PKCS1_OAEP_PADDING |
| |
| EME-OAEP as defined in PKCS #1 v2.0 with SHA-1, MGF1 and an empty |
| encoding parameter. This mode is recommended for all new applications. |
| |
| =item RSA_SSLV23_PADDING |
| |
| PKCS #1 v1.5 padding with an SSL-specific modification that denotes |
| that the server is SSL3 capable. |
| |
| =item RSA_NO_PADDING |
| |
| Raw RSA encryption. This mode should I<only> be used to implement |
| cryptographically sound padding modes in the application code. |
| Encrypting user data directly with RSA is insecure. |
| |
| =back |
| |
| B<flen> must be less than RSA_size(B<rsa>) - 11 for the PKCS #1 v1.5 |
| based padding modes, less than RSA_size(B<rsa>) - 41 for |
| RSA_PKCS1_OAEP_PADDING and exactly RSA_size(B<rsa>) for RSA_NO_PADDING. |
| The random number generator must be seeded prior to calling |
| RSA_public_encrypt(). |
| |
| RSA_private_decrypt() decrypts the B<flen> bytes at B<from> using the |
| private key B<rsa> and stores the plaintext in B<to>. B<to> must point |
| to a memory section large enough to hold the decrypted data (which is |
| smaller than RSA_size(B<rsa>)). B<padding> is the padding mode that |
| was used to encrypt the data. |
| |
| =head1 RETURN VALUES |
| |
| RSA_public_encrypt() returns the size of the encrypted data (i.e., |
| RSA_size(B<rsa>)). RSA_private_decrypt() returns the size of the |
| recovered plaintext. |
| |
| On error, -1 is returned; the error codes can be |
| obtained by L<ERR_get_error(3)|ERR_get_error(3)>. |
| |
| =head1 CONFORMING TO |
| |
| SSL, PKCS #1 v2.0 |
| |
| =head1 SEE ALSO |
| |
| L<ERR_get_error(3)|ERR_get_error(3)>, L<rand(3)|rand(3)>, L<rsa(3)|rsa(3)>, |
| L<RSA_size(3)|RSA_size(3)> |
| |
| =head1 HISTORY |
| |
| The B<padding> argument was added in SSLeay 0.8. RSA_NO_PADDING is |
| available since SSLeay 0.9.0, OAEP was added in OpenSSL 0.9.2b. |
| |
| =cut |
