RSA_PUBLIC_ENCRYPT(3) OpenSSL RSA_PUBLIC_ENCRYPT(3)

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** (usu-
ally 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, less than RSA_size(**rsa**) - 41 for
RSA_PKCS1_OAEP_PADDING and exactly RSA_size(**rsa**) for
RSA_NO_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.
MirBSD #10-current 2005-04-29 1
RSA_PUBLIC_ENCRYPT(3) OpenSSL RSA_PUBLIC_ENCRYPT(3)

*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_get_error*(3), *rand*(3), *rsa*(3), *RSA_size*(3)

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.
MirBSD #10-current 2005-04-29 2