init

part2/alice.py

@@ -0,0 +1,25 @@
+from Crypto.PublicKey import RSA
+from Crypto.Signature import pss
+from Crypto.Hash import SHA256
+
+key = RSA.generate(2048)
+
+# Generate / write alice pub key
+with open("alice_public.pem", "wb") as file:
+    file.write(key.publickey().export_key())
+
+m = input("Message: ").encode()
+
+h = SHA256.new(m)
+
+signer = pss.new(key)
+
+signature: bytes = signer.sign(h)
+
+print(f'Signature: {signature}')
+
+with open("sigtext", 'wb') as file:
+    file.write(m + signature)
+
+
+

part2/bob.py

@@ -0,0 +1,25 @@
+from Crypto.PublicKey import RSA
+from Crypto.Signature import pss
+from Crypto.Hash import SHA256
+
+with open("alice_public.pem", 'rb') as file:
+    alice_pub = RSA.import_key(file.read())
+
+with open('sigtext', 'rb') as file:
+    data = file.read()
+
+m = data[:18]
+sig = data[18:]
+
+h = SHA256.new(m)
+
+verifier = pss.new(alice_pub)
+
+try:
+    verifier.verify(h, sig)
+    print("Signature is valid")
+
+except (ValueError, TypeError) as e:
+    print("Signature is invalid")
+
+