RSA_generate_key 3 2003-07-24 0.9.9-dev OpenSSL

NAME

RSA_generate_key - generate RSA key pair

LIBRARY

libcrypto, -lcrypto

SYNOPSIS


 #include 


 RSA *RSA_generate_key(int num, unsigned long e,
    void (*callback)(int,int,void *), void *cb_arg);

DESCRIPTION

_R_S_A___g_e_n_e_r_a_t_e___k_e_y_(_) generates a key pair and returns it in a newly allocated RRSSAA structure. The pseudo-random number generator must be seeded prior to calling _R_S_A___g_e_n_e_r_a_t_e___k_e_y_(_).

The modulus size will be nnuumm bits, and the public exponent will be ee. Key sizes with nnuumm < 1024 should be considered insecure. The exponent is an odd number, typically 3, 17 or 65537.

A callback function may be used to provide feedback about the progress of the key generation. If ccaallllbbaacckk is not NNUULLLL, it will be called as follows:

· While a random prime number is generated, it is called as
described in _B_N___g_e_n_e_r_a_t_e___p_r_i_m_e(3).
· When the n-th randomly generated prime is rejected as not
suitable for the key, ccaallllbbaacckk((22,, nn,, ccbb__aarrgg)) is called.
· When a random p has been found with p-1 relatively prime to ee,
it is called as ccaallllbbaacckk((33,, 00,, ccbb__aarrgg)).

The process is then repeated for prime q with ccaallllbbaacckk((33,, 11,, ccbb__aarrgg)).

RETURN VALUE

If key generation fails, _R_S_A___g_e_n_e_r_a_t_e___k_e_y_(_) returns NNUULLLL; the error codes can be obtained by _E_R_R___g_e_t___e_r_r_o_r(3).

BUGS

ccaallllbbaacckk((22,, xx,, ccbb__aarrgg)) is used with two different meanings.

_R_S_A___g_e_n_e_r_a_t_e___k_e_y_(_) goes into an infinite loop for illegal input values.

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___f_r_e_e(3)

HISTORY

The ccbb__aarrgg argument was added in SSLeay 0.9.0.