diff --git a/CMakeLists.txt b/CMakeLists.txt
index 58138fa..1b3e8b7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -54,6 +54,7 @@ set( LIB_SOURCE
 include(OpenSSL)
 set (LIB_SOURCE ${LIB_SOURCE}
 	src/openssl/ec.cpp
+	src/openssl/ecdsa.cpp
 	src/openssl/hash.cpp
 	src/openssl/helpers.c
 	src/openssl/recovery.c
diff --git a/src/openssl/ecdsa.cpp b/src/openssl/ecdsa.cpp
new file mode 100644
index 0000000..a897166
--- /dev/null
+++ b/src/openssl/ecdsa.cpp
@@ -0,0 +1,185 @@
+/**
+ * MIT License
+ *
+ * Copyright (c) 2019-2021 EOS Sw/eden
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include <openssl/ec.h>
+#include <openssl/bn.h>
+#include <openssl/ecdsa.h>
+#include <libeosio/ec.hpp>
+#include "internal.h"
+
+namespace libeosio {
+
+extern BN_CTX *ctx;
+
+int ecdsa_sign(const ec_privkey_t& key, const sha256_t* digest, ec_signature_t& sig) {
+
+	int rc = -1;
+	EC_POINT *pub;
+	const EC_GROUP *group;
+	ECDSA_SIG *ecdsa_sig;
+	EC_KEY *ec_key;
+
+	if ((ec_key = EC_KEY_new_secp256k1()) == NULL) {
+		return -1;
+	}
+
+	if (EC_KEY_oct2priv(ec_key, key.data(), key.size()) < 0) {
+		goto err1;
+	}
+
+	group = EC_KEY_get0_group(ec_key);
+	if (group == NULL) {
+		goto err1;
+	}
+
+	if (calculate_pubkey(group, ec_key, &pub) == 0) {
+		goto err2;
+	}
+
+	while (1) {
+		int recid = -1;
+		const BIGNUM *r, *s;
+		EC_KEY* tmpk;
+
+		ecdsa_sig = ECDSA_do_sign(digest->data, 32, ec_key);
+		if (ecdsa_sig == NULL) {
+			goto err2;
+		}
+
+		// Get R and S numbers.
+		r = ECDSA_SIG_get0_r(ecdsa_sig);
+		s = ECDSA_SIG_get0_s(ecdsa_sig);
+
+		tmpk = EC_KEY_new_by_curve_name( NID_secp256k1 );
+		for (int i = 0; i < 4; i++) {
+			if (ECDSA_SIG_recover_key_GFp(tmpk, r, s, digest->data, sizeof(digest->data), i, 1) == 1) {
+				const EC_POINT *p = EC_KEY_get0_public_key(tmpk);
+
+				// Compare public keys
+				if (EC_POINT_cmp(group, pub, p, ctx) == 0) {
+					recid = i;
+					break;
+				}
+			}
+		}
+
+		EC_KEY_free( tmpk );
+
+		// Could not find recovery id.
+		if (recid == -1) {
+			goto err2;
+		}
+
+		if (ECDSA_SIG_serialize(ecdsa_sig, recid, sig.data()) == 0) {
+			goto out;
+		}
+	}
+
+out:	rc = 0;
+err2:
+	EC_POINT_free(pub);
+err1:
+	EC_KEY_free(ec_key);
+	return rc;
+}
+
+int ecdsa_verify(const sha256_t* digest, const ec_signature_t& sig, const ec_pubkey_t& pub) {
+
+	int recid, ret = -1;
+	EC_POINT *point;
+	const EC_GROUP *group;
+	ECDSA_SIG* ecdsa_sig;
+	EC_KEY *ec_key;
+
+	ec_key = EC_KEY_new_by_curve_name( NID_secp256k1 );
+	if (ec_key == NULL) {
+		return -1;
+	}
+
+	if ((ecdsa_sig = ECDSA_SIG_new()) == NULL) {
+		goto err1;
+	}
+
+	if (ECDSA_SIG_unserialize(sig.data(), ecdsa_sig, &recid) == 0) {
+		goto err2;
+	}
+
+	if ((group = EC_KEY_get0_group(ec_key)) == NULL) {
+		goto err2;
+	}
+
+	if ((point = EC_POINT_new(group)) == NULL) {
+		goto err2;
+	}
+
+	if (EC_POINT_oct2point(group, point, pub.data(), EC_PUBKEY_SIZE, ctx) == 0) {
+		goto err3;
+	}
+
+	if (EC_KEY_set_public_key(ec_key, point) == 0) {
+		goto err3;
+	}
+
+	if (ECDSA_do_verify(digest->data, 32, ecdsa_sig, ec_key) == 1) {
+		ret = 0;
+	}
+
+err3:	EC_POINT_free(point);
+err2:	ECDSA_SIG_free(ecdsa_sig);
+err1:	EC_KEY_free(ec_key);
+	return ret;
+}
+
+int ecdsa_recover(const sha256_t* digest, const ec_signature_t& sig, ec_pubkey_t& key) {
+
+	int recid;
+	int ret = -1;
+	BIGNUM *r, *s;
+	EC_KEY *ec_key;
+
+	// Initialize ec variables.
+	if ((ec_key = EC_KEY_new_secp256k1()) == NULL) goto err1;
+
+	// Unserialize signature into r,s,recid components.
+	ECDSA_SIG_unserialize_rs(sig.data(), &r, &s, &recid);
+
+	// Recover public key.
+	if (ECDSA_SIG_recover_key_GFp(ec_key, r, s, digest->data, 32, recid, 1) == 1) {
+
+		// Encode point to binary compressed format.
+		const EC_POINT *p = EC_KEY_get0_public_key(ec_key);
+		const EC_GROUP *g = EC_KEY_get0_group(ec_key);
+		if (EC_POINT_encode(g, p, key.data(), EC_PUBKEY_SIZE, ctx) == 0) {
+			goto err4;
+		}
+
+		ret = 0;
+	}
+
+err4:	BN_free(s);
+err3:	BN_free(r);
+err2:   EC_KEY_free(ec_key);
+err1:	return ret;
+}
+
+} // namespace libeosio
\ No newline at end of file