Switched to cryptography instead of ecdsa for signatures

apps/generate_key.py

@@ -1,21 +1,47 @@
-import ecdsa
 import os.path
 from sys import exit
 
+from cryptography.hazmat.backends import default_backend
+from cryptography.hazmat.primitives import serialization
+from cryptography.hazmat.primitives.asymmetric import ec
+
+
 # Simple tool to generate an ECDSA private key using the secp256k1 curve and save private and public keys
 # as signing_key_priv.pem and signing_key_pub.pem
 
 FILE_NAME_PRIV = 'signing_key_priv.pem'
 FILE_NAME_PUB = 'signing_key_pub.pem'
 
+
+def save_sk(sk, filename):
+    pem = sk.private_bytes(
+        encoding=serialization.Encoding.PEM,
+        format=serialization.PrivateFormat.TraditionalOpenSSL,
+        encryption_algorithm=serialization.NoEncryption()
+    )
+    with open(filename, 'wb') as pem_out:
+        pem_out.write(pem)
+
+
+def save_pk(pk, filename):
+    pem = pk.public_bytes(
+        encoding=serialization.Encoding.PEM,
+        format=serialization.PublicFormat.SubjectPublicKeyInfo
+    )
+    with open(filename, 'wb') as pem_out:
+        pem_out.write(pem)
+
+
 if __name__ == '__main__':
     if os.path.exists(FILE_NAME_PRIV):
         print("A key with name \"{}\" already exists. Aborting.".format(FILE_NAME_PRIV))
         exit(1)
 
-    sk = ecdsa.SigningKey.generate(curve=ecdsa.SECP256k1)
-    pk = sk.get_verifying_key()
+    sk = ec.generate_private_key(
+        ec.SECP256K1, default_backend()
+    )
+    pk = sk.public_key()
 
-    open(FILE_NAME_PRIV, 'wb').write(sk.to_pem())
-    open(FILE_NAME_PUB, 'wb').write(pk.to_pem())
+    save_sk(sk, FILE_NAME_PRIV)
+    save_pk(pk, FILE_NAME_PUB)
     print("Saved private key \"{}\" and public key \"{}\".".format(FILE_NAME_PRIV, FILE_NAME_PUB))