RSA_public_encrypt, RSA_private_decrypt − RSA public key cryptography |
#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); |
RSA_public_encrypt() encrypts the flen bytes at from (usually a session key) using the public key rsa and stores the ciphertext in to. to must point to RSA_size(rsa) bytes of memory. padding denotes one of the following modes: |
RSA_PKCS1_PADDING |
PKCS #1 v1.5 padding. This currently is the most widely used mode. |
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. |
RSA_SSLV23_PADDING |
PKCS #1 v1.5 padding with an SSL −specific modification that denotes that the server is SSL3 capable. |
RSA_NO_PADDING |
Raw RSA encryption. This mode should only be used to implement cryptographically sound padding modes in the application code. Encrypting user data directly with RSA is insecure. |
flen must be less than RSA_size(rsa) − 11 for the PKCS #1 v1.5 based padding modes, and less than RSA_size(rsa) − 21 for RSA_PKCS1_OAEP_PADDING . The random number generator must be seeded prior to calling RSA_public_encrypt(). RSA_private_decrypt() decrypts the flen bytes at from using the private key rsa and stores the plaintext in to. to must point to a memory section large enough to hold the decrypted data (which is smaller than RSA_size(rsa)). padding is the padding mode that was used to encrypt the data. |
RSA_public_encrypt() returns the size of the encrypted data (i.e., RSA_size(rsa)). RSA_private_decrypt() returns the size of the recovered plaintext. On error, −1 is returned; the error codes can be obtained by ERR_get_error(3). |
SSL, PKCS #1 v2.0 |
err(3), rand(3), rsa(3), RSA_size(3) |
The RSA_PKCS1_RSAref(3) method supports only the RSA_PKCS1_PADDING mode. |
The 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. |