+int EVP_add_kdf(const EVP_KDF *kdf);
+
+/* struct evp_kdf_impl_st is defined by the implementation */
+typedef struct evp_kdf_impl_st EVP_KDF_IMPL;
+struct evp_kdf_st {
+ int type;
+ EVP_KDF_IMPL *(*new) (void);
+ void (*free) (EVP_KDF_IMPL *impl);
+ void (*reset) (EVP_KDF_IMPL *impl);
+ int (*ctrl) (EVP_KDF_IMPL *impl, int cmd, va_list args);
+ int (*ctrl_str) (EVP_KDF_IMPL *impl, const char *type, const char *value);
+ size_t (*size) (EVP_KDF_IMPL *impl);
+ int (*derive) (EVP_KDF_IMPL *impl, unsigned char *key, size_t keylen);
+};
+
+extern const EVP_KDF pbkdf2_kdf_meth;
+extern const EVP_KDF scrypt_kdf_meth;
+extern const EVP_KDF tls1_prf_kdf_meth;
+extern const EVP_KDF hkdf_kdf_meth;
+extern const EVP_KDF sshkdf_kdf_meth;
+extern const EVP_KDF ss_kdf_meth;
+extern const EVP_KDF x963_kdf_meth;
+extern const EVP_KDF x942_kdf_meth;