init

.gitignore

@@ -0,0 +1,5 @@
+k
+mactext
+
+*.pem
+sigtext

part1/alice.py

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+import hmac
+import hashlib
+
+import secrets
+
+# Generate and write shared key
+
+shared_secret: bytes = secrets.token_bytes(16)
+
+with open('k', 'wb') as file:
+    file.write(shared_secret)
+
+# Take in message and compute hmac
+m = input("Message: ").encode()
+
+hmac_object: hmac.HMAC = hmac.new(shared_secret, m, hashlib.sha256)
+m_hash = hmac_object.digest()
+
+print(f'HMAC: {m_hash}')
+
+# Write hmac digest and message
+
+with open('mactext', 'wb') as file:
+    file.write(m + m_hash)
+
+
+
+

part1/bob.py

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+import hmac
+import hashlib
+
+
+# Import shared secret
+with open('k', 'rb') as file:
+    shared_key = file.read()
+
+# Compute hmac
+with open('mactext', 'rb') as file:
+    data = file.read()
+
+m = data[:18]
+m_hash = data[18:]
+
+hmac_oject: hmac.HMAC = hmac.new(shared_key, m, hashlib.sha256)
+derived_hmac = hmac_oject.digest()
+print(f'Derived HMAC: {hmac_oject.digest()}')
+
+if derived_hmac == m_hash:
+    print("HMAC matches message")
+
+else:
+    print("HMAC does not match message")
+
+
+
+
+

part2/alice.py

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+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

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+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")
+
+

part3/speed_test.py

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+import time
+
+import hmac
+import hashlib
+import secrets
+
+m = input("Message: ").encode()
+
+key = secrets.token_bytes(16)
+
+sig_gen_times = []
+sig_ver_times = []
+
+# HMAC
+
+for n in range(100):
+
+    start = time.time()
+    hmac_object = hmac.new(key, m, hashlib.sha256)
+    end = time.time()
+
+    sig_gen_times.append(end - start)
+
+    start = time.time()
+    assert hmac_object.digest() == hmac.new(key, m, hashlib.sha256).digest()
+    end = time.time()
+
+    sig_ver_times.append(end - start)
+
+avg_gen_time = (sum(sig_gen_times)/len(sig_gen_times)) * 1000
+avg_ver_time = (sum(sig_ver_times)/len(sig_ver_times)) * 1000
+
+print(f"Average HMAC Generation Time: {avg_gen_time} ms")
+print(f"Average HMAC Verification Time: {avg_ver_time} ms")
+
+# RSA
+
+from Crypto.PublicKey import RSA
+from Crypto.Signature import pss
+from Crypto.Hash import SHA256
+
+sig_gen_times = []
+sig_ver_times = []
+
+key = RSA.generate(2048)
+
+for n in range(100):
+
+    start = time.time()
+    h = SHA256.new(m)
+    signer = pss.new(key)
+    signature = signer.sign(h)
+    end = time.time()
+
+    sig_gen_times.append(end - start)
+    public_key = key.publickey()
+
+    start = time.time()
+    h = SHA256.new(m)
+    verifier = pss.new(public_key)
+    verifier.verify(h, signature)
+    end = time.time()
+
+    sig_ver_times.append(end - start)
+
+avg_gen_time = (sum(sig_gen_times)/len(sig_gen_times)) * 1000
+avg_ver_time = (sum(sig_ver_times)/len(sig_ver_times)) * 1000
+
+print(f"Average RSA Signature Generation Time: {avg_gen_time} ms")
+print(f"Average RSA Signature Verification Time: {avg_ver_time} ms")