static int cca_rsa_sign(int type, const unsigned char *m, unsigned int m_len,
unsigned char *sigret, unsigned int *siglen, const RSA *rsa);
static int cca_rsa_verify(int dtype, const unsigned char *m, unsigned int m_len,
static int cca_rsa_sign(int type, const unsigned char *m, unsigned int m_len,
unsigned char *sigret, unsigned int *siglen, const RSA *rsa);
static int cca_rsa_verify(int dtype, const unsigned char *m, unsigned int m_len,