+int ecdsa_simple_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
+ BIGNUM **rp);
+ECDSA_SIG *ecdsa_simple_sign_sig(const unsigned char *dgst, int dgst_len,
+ const BIGNUM *in_kinv, const BIGNUM *in_r,
+ EC_KEY *eckey);
+int ecdsa_simple_verify_sig(const unsigned char *dgst, int dgst_len,
+ const ECDSA_SIG *sig, EC_KEY *eckey);