RSA_public_encrypt(3) OpenSSL RSA_public_encrypt(3)
NAME
RSA_public_encrypt, RSA_private_decrypt  RSA public key cryptography
LIBRARY
libcrypto, lcrypto
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);
DESCRIPTION
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
EMEOAEP as defined in PKCS #1 v2.0 with SHA1, MGF1 and an empty
encoding parameter. This mode is recommended for all new applica
tions.
RSA_SSLV23_PADDING
PKCS #1 v1.5 padding with an SSLspecific 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)  41 for RSA_PKCS1_OAEP_PAD
DING. 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 sec
tion 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.
RETURN VALUES
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).
CONFORMING TO
SSL, PKCS #1 v2.0
SEE ALSO
ERR_get_error(3), openssl_rand(3), openssl_rsa(3), RSA_size(3)
HISTORY
The padding argument was added in SSLeay 0.8. RSA_NO_PADDING is avail
able since SSLeay 0.9.0, OAEP was added in OpenSSL 0.9.2b.
3rd Berkeley Distribution 0.9.7d RSA_public_encrypt(3)
