RSA_public_encrypt 3 2005-03-25 0.9.9-dev OpenSSL

NAME

RSA_public_encrypt, RSA_private_decrypt - RSA public key cryptography

LIBRARY

libcrypto, -lcrypto

SYNOPSIS


 #include 


 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

_R_S_A___p_u_b_l_i_c___e_n_c_r_y_p_t_(_) encrypts the fflleenn bytes at ffrroomm (usually a session key) using the public key rrssaa and stores the ciphertext in ttoo. ttoo must point to RSA_size(rrssaa) bytes of memory.

ppaaddddiinngg 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 _o_n_l_y be used to implement
cryptographically sound padding modes in the application code. Encrypting user data directly with RSA is insecure.

fflleenn must be less than RSA_size(rrssaa) - 11 for the PKCS #1 v1.5 based padding modes, less than RSA_size(rrssaa) - 41 for RSA_PKCS1_OAEP_PADDING and exactly RSA_size(rrssaa) for RSA_NO_PADDING. The random number generator must be seeded prior to calling _R_S_A___p_u_b_l_i_c___e_n_c_r_y_p_t_(_).

_R_S_A___p_r_i_v_a_t_e___d_e_c_r_y_p_t_(_) decrypts the fflleenn bytes at ffrroomm using the private key rrssaa and stores the plaintext in ttoo. ttoo must point to a memory section large enough to hold the decrypted data (which is smaller than RSA_size(rrssaa)). ppaaddddiinngg is the padding mode that was used to encrypt the data.

RETURN VALUES

_R_S_A___p_u_b_l_i_c___e_n_c_r_y_p_t_(_) returns the size of the encrypted data (i.e., RSA_size(rrssaa)). _R_S_A___p_r_i_v_a_t_e___d_e_c_r_y_p_t_(_) returns the size of the recovered plaintext.

On error, -1 is returned; the error codes can be obtained by _E_R_R___g_e_t___e_r_r_o_r(3).

CONFORMING TO

SSL, PKCS #1 v2.0

SEE ALSO

_E_R_R___g_e_t___e_r_r_o_r(3), _o_p_e_n_s_s_l___r_a_n_d(3), _o_p_e_n_s_s_l___r_s_a(3), _R_S_A___s_i_z_e(3)

HISTORY

The ppaaddddiinngg 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.