diff --git a/larky/src/main/resources/vendor/jose/backends/pycrypto_backend.star b/larky/src/main/resources/vendor/jose/backends/pycrypto_backend.star
index c6605f604..2168b315f 100644
--- a/larky/src/main/resources/vendor/jose/backends/pycrypto_backend.star
+++ b/larky/src/main/resources/vendor/jose/backends/pycrypto_backend.star
@@ -281,8 +281,9 @@ def RSAKey(key, algorithm):
     self._process_cert = _process_cert
 
     def sign(msg):
-        pkcs1_signer = safe(PKCS1_v1_5_Signature.new(self.prepared_key).sign)
-        return pkcs1_signer(self.hash_alg.new(msg))().unwrap()
+        signature = PKCS1_v1_5_Signature.new(self.prepared_key)
+        res = Ok(signature.sign).map(lambda sign: sign(self.hash_alg.new(msg)))
+        return res.unwrap()
     self.sign = sign
 
     def verify(msg, sig):
diff --git a/larky/src/test/resources/vendor_tests/jose/test_jose.star b/larky/src/test/resources/vendor_tests/jose/test_jose.star
index 75d307e59..4e1414678 100644
--- a/larky/src/test/resources/vendor_tests/jose/test_jose.star
+++ b/larky/src/test/resources/vendor_tests/jose/test_jose.star
@@ -12,6 +12,7 @@ load("@vendor//jose/backends", AESKey="AESKey")
 load("@vendor//jose/constants", ALGORITHMS="ALGORITHMS")
 load("@vendor//jose/jwe", jwe="jwe")
 load("@vendor//jose/jwk", jwk="jwk")
+load("@vendor//jose/utils", base64url_encode="base64url_encode")
 
 
 
@@ -127,6 +128,74 @@ def test_pbkdf2_hmac_aes_key_wrapped():
     d = cipher.decrypt(ctBytes) # does not verify or authenticate the tag..
     asserts.assert_that(base64.b64encode(d)).is_equal_to(b'NTQ0Mjg4MzAxMDAxNjc5Mg==')
 
+def test_sign_with_rsa():
+    rsa_private_key = """-----BEGIN RSA PRIVATE KEY-----
+                        MIIEogIBAAKCAQEAnzJokBF2RIiyOIS8iCJmUKDvg1kFvs+elNeNWb9s+xfJk/ka
+                        pqvs4b5wFzLGmZbmWeWWw4reGyYFk1bmfCKbC+58yciH/Iy2hwOWsvL1MLmQG0lo
+                        wD9joD3uuvFbaPecyHQ9VLE7SBx2w8uffn/PNUtu7/h+9vLP+RFOCIkDVdfHRD1F
+                        Llx1rtXVecpfXu+RE5fVv+FIitzB3VTE3ZBO/oBYp9K/M9xELQ9G9bKpK3Jddw/Z
+                        MJ2rF3Kf6SQHY0907LA9RTIbdg4MCBNdzHeOE42KliOjsxs6ZqFkeIBRuEINlkaC
+                        Y0/Ki+q2pEgHwgIdlfCYC+qA0xOJsk01rhV6LQIDAQABAoIBABjKA6gzX+QqGP5e
+                        BPF50c7KUKF2UkO1Fq98pSENgs3SlWv6RSEg8mDwg4nJOU2fRr1G1+QZEp7Nm96m
+                        kHtR9Cy2dS4CkNJNovqBH4078dwleQAWvT36YOwJ2Mu5W4+LxxkbqJUwh9ehvwic
+                        A3jyM/TLiznIyxRvGN1iyXDgzOkn0mAOHL+m+iwiqVb9xS/7NELbOFxYxyzlqmUn
+                        HC61t2zLRS2aUCGv+HVfhfdBo7jNsH9NnXqNU2ghV9oi9Ssgv8xyQC4nlRmHe1+s
+                        vw4ZFKT1Ybjyhj3rG1LXyDJHmZwc/ktNXSuPHiypwM8KLU6Tx2uBheGwKVciVbbV
+                        WCvnbKECgYEA3AI22eXKc7LgjunQNeIn00W6IJV3zDVt2ELMymYTVpUKILpZkBJG
+                        l8QrMdkyhdMPcRbQhJL427uNWWkKiuRNVWOwU8Yr6/eOjQ7qBmrNRrjL3STt4uW4
+                        pFd1qO9gjvdJ7PdL7sf0LLGeqQ0jfguSCN3L19I33YTsjgyQ8HktTMkCgYEAuT1y
+                        fk3rpLzYt1TfV0ZvSHOYcMSJDjcoo9hBJyYjPDsi1YtmoJgP4zalCJLwssZAbENl
+                        XbFQ38dYF+EJH20GHRjQooS5ffWkBfSrCpkTfqrno+bBbQE6hKapNeCT/Fubk25Y
+                        nHbM/Fswf0JUBDzR6lej4C3oC3QwvsKVIu7tiEUCgYBtdJiPbZh8WUkJMOAKfrpr
+                        jOwd297e9NHyXsF+DKygTcPdJnj6iW0fglQvF6zgEXJERCJ3Ypt2zmdzTSQWl6C1
+                        08Pc2eHuIpqEKSBbEvWPss6R9hZ35Oworu51nqo+Vl8sCph3cnlTZwbVehjnU6BS
+                        0u3gMNDkX4ZE4ZGWYeMcqQKBgCmHmjSw+YSshhXMJGpnsylWKTYXCfcy7JyXLjw9
+                        s6acR3oCz9ZvYRh6ttNORkJ+ahEbpw0zZMNW6Owpmqb+BWHen1/gS8numYBwUyyE
+                        FzfNzzMS2Ai9PsZgqw0WNXddfmq2UY16oQhu1Veioj10+UcFsQrgn+Z5fTg3XcJA
+                        OObVAoGAPk7GL8WELvJGBNYcLFZ4TxgtD7uPxkA+PwMMv/xwHjZjiCKsL5HlYYuD
+                        Qgz4dQy0OW02mfC5LDkCHzOO3m5suiodTJpDiU0arcbtXh3QW3IWwKXMwG2pDLsh
+                        vyExhzkL/cPs+hXX5Uvuwh3RATzdlGx9Vf6NDaF20EvegzK42wY=
+                        -----END RSA PRIVATE KEY-----"""
+    header = {
+        "typ": "JWT",
+        "alg": 'RS256'
+    }
+
+    json_header = bytes(json.dumps(header,), 'utf-8')
+
+    headers = base64url_encode(json_header)
+    encoded_payload = base64url_encode(bytes(json.dumps({'a': 'b'}), 'utf-8'))
+
+    signing_input = bytes([0x2e]).join([headers, encoded_payload])
+    k = jwk.construct(rsa_private_key, 'RS256')
+    sign = k.sign(signing_input)
+    encoded_signature = base64url_encode(sign)
+    
+    encoded_string = b".".join([headers, encoded_payload, encoded_signature])
+
+def test_sign_with_ecc():
+    es_private_key = """-----BEGIN EC PRIVATE KEY-----
+                        MHcCAQEEIDcv6AeZhfUH20LCzlHKr6SZyWK5LnQQrWN5TigDmTcwoAoGCCqGSM49
+                        AwEHoUQDQgAEQ4+x/eCyT+7mnjPgT0iIf7PBB2W7YHDi3qvbNMZm+Its/M+6eCGk
+                        qhcJT26DWf2EMncfCX4okTxVST/r/ohGXA==
+                        -----END EC PRIVATE KEY-----"""
+    header = {
+        "typ": "JWT",
+        "alg": 'ES256'
+    }
+
+    json_header = bytes(json.dumps(header), 'utf-8')
+
+    headers = base64url_encode(json_header)
+    encoded_payload = base64url_encode(bytes(json.dumps({'a': 'b'}), 'utf-8'))
+
+    signing_input = bytes([0x2e]).join([headers, encoded_payload])
+    k = jwk.construct(es_private_key, 'ES256')
+    sign = k.sign(signing_input)
+    encoded_signature = base64url_encode(sign)
+    
+    encoded_string = b".".join([headers, encoded_payload, encoded_signature])
+
 
 def _testsuite():
     _suite = unittest.TestSuite()
@@ -154,6 +223,8 @@ def _testsuite():
     _suite.addTest(unittest.FunctionTestCase(test_vector_RFC_5649_20_wrap))
     _suite.addTest(unittest.FunctionTestCase(test_vector_RFC_5649_20_unwrap))
     _suite.addTest(unittest.FunctionTestCase(test_pbkdf2_hmac_aes_key_wrapped))
+    _suite.addTest(unittest.FunctionTestCase(test_sign_with_ecc))
+    _suite.addTest(unittest.FunctionTestCase(test_sign_with_rsa))
 
     return _suite