+/** Returns the maximum length of the DER encoded signature
+ * \param eckey EC_KEY object
+ * \return numbers of bytes required for the DER encoded signature
+ */
+int ECDSA_size(const EC_KEY *eckey);
+
+/********************************************************************/
+/* EC_KEY_METHOD constructors, destructors, writers and accessors */
+/********************************************************************/
+
+EC_KEY_METHOD *EC_KEY_METHOD_new(const EC_KEY_METHOD *meth);
+void EC_KEY_METHOD_free(EC_KEY_METHOD *meth);
+void EC_KEY_METHOD_set_init(EC_KEY_METHOD *meth,
+ int (*init)(EC_KEY *key),
+ void (*finish)(EC_KEY *key),
+ int (*copy)(EC_KEY *dest, const EC_KEY *src),
+ int (*set_group)(EC_KEY *key, const EC_GROUP *grp),
+ int (*set_private)(EC_KEY *key,
+ const BIGNUM *priv_key),
+ int (*set_public)(EC_KEY *key,
+ const EC_POINT *pub_key));
+
+void EC_KEY_METHOD_set_keygen(EC_KEY_METHOD *meth,
+ int (*keygen)(EC_KEY *key));
+
+void EC_KEY_METHOD_set_compute_key(EC_KEY_METHOD *meth,
+ int (*ckey)(unsigned char **psec,
+ size_t *pseclen,
+ const EC_POINT *pub_key,
+ const EC_KEY *ecdh));
+
+void EC_KEY_METHOD_set_sign(EC_KEY_METHOD *meth,
+ int (*sign)(int type, const unsigned char *dgst,
+ int dlen, unsigned char *sig,
+ unsigned int *siglen,
+ const BIGNUM *kinv, const BIGNUM *r,
+ EC_KEY *eckey),
+ int (*sign_setup)(EC_KEY *eckey, BN_CTX *ctx_in,
+ BIGNUM **kinvp, BIGNUM **rp),
+ ECDSA_SIG *(*sign_sig)(const unsigned char *dgst,
+ int dgst_len,
+ const BIGNUM *in_kinv,
+ const BIGNUM *in_r,
+ EC_KEY *eckey));
+
+void EC_KEY_METHOD_set_verify(EC_KEY_METHOD *meth,
+ int (*verify)(int type, const unsigned
+ char *dgst, int dgst_len,
+ const unsigned char *sigbuf,
+ int sig_len, EC_KEY *eckey),
+ int (*verify_sig)(const unsigned char *dgst,
+ int dgst_len,
+ const ECDSA_SIG *sig,
+ EC_KEY *eckey));
+
+void EC_KEY_METHOD_get_init(EC_KEY_METHOD *meth,
+ int (**pinit)(EC_KEY *key),
+ void (**pfinish)(EC_KEY *key),
+ int (**pcopy)(EC_KEY *dest, const EC_KEY *src),
+ int (**pset_group)(EC_KEY *key,
+ const EC_GROUP *grp),
+ int (**pset_private)(EC_KEY *key,
+ const BIGNUM *priv_key),
+ int (**pset_public)(EC_KEY *key,
+ const EC_POINT *pub_key));
+
+void EC_KEY_METHOD_get_keygen(EC_KEY_METHOD *meth,
+ int (**pkeygen)(EC_KEY *key));
+
+void EC_KEY_METHOD_get_compute_key(EC_KEY_METHOD *meth,
+ int (**pck)(unsigned char **psec,
+ size_t *pseclen,
+ const EC_POINT *pub_key,
+ const EC_KEY *ecdh));
+
+void EC_KEY_METHOD_get_sign(EC_KEY_METHOD *meth,
+ int (**psign)(int type, const unsigned char *dgst,
+ int dlen, unsigned char *sig,
+ unsigned int *siglen,
+ const BIGNUM *kinv, const BIGNUM *r,
+ EC_KEY *eckey),
+ int (**psign_setup)(EC_KEY *eckey, BN_CTX *ctx_in,
+ BIGNUM **kinvp, BIGNUM **rp),
+ ECDSA_SIG *(**psign_sig)(const unsigned char *dgst,
+ int dgst_len,
+ const BIGNUM *in_kinv,
+ const BIGNUM *in_r,
+ EC_KEY *eckey));
+
+void EC_KEY_METHOD_get_verify(EC_KEY_METHOD *meth,
+ int (**pverify)(int type, const unsigned
+ char *dgst, int dgst_len,
+ const unsigned char *sigbuf,
+ int sig_len, EC_KEY *eckey),
+ int (**pverify_sig)(const unsigned char *dgst,
+ int dgst_len,
+ const ECDSA_SIG *sig,
+ EC_KEY *eckey));
+