Creation of ECBPlaintextAttack

ECBPlaintextAttack/README.md

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+# ECB Plaintext Attack
+A sample AES-ECB server and client for demonstrating a chosen plaintext attack.
+
+For more information, see the following blog post - https://www.doyler.net/security-not-included/ecb-chosen-plaintext-attack

ECBPlaintextAttack/ecbAttack.py

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+#!/usr/bin/python
+
+import math
+import socket
+import sys
+
+def chunkstring(string, length):
+    return (string[0+i:length+i] for i in range(0, len(string), length))
+
+def roundup(x, base=10):
+    return int(math.ceil(x / (base + 0.0))) * base
+
+s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+
+server_address = ('localhost', 10000)
+s.connect(server_address)
+
+try:
+    found = False
+    secret = ""
+
+    secretLen = 0
+    #prependChars = "ENCRYPT:"
+    prependChars = ""
+
+    message = "A"
+    s.sendall(message)
+    data = s.recv(2048)
+    output = list(chunkstring(data, 32))
+    initialLen = len(output)
+
+    curLen = 0
+
+    while (curLen <= initialLen):
+        message += "A"
+        s.sendall(message)
+        data = s.recv(2048)
+        output = list(chunkstring(data, 32))
+        curLen = len(output)
+
+    extra = len(message) - 1
+
+    secretLen = ((curLen - 1) * 16) - extra - len(prependChars)
+
+    print "SECRETLEN: " + str(secretLen)
+
+    while not found:
+        initialBlock = "A" * (16 - len(prependChars))
+        fullLen = roundup(secretLen, 16)
+        prepend = "B" * (fullLen - len(secret) - 1)
+        message1 = initialBlock + prepend
+
+        s.sendall(message1)
+        data = s.recv(8192)
+        initialReturn = list(chunkstring(data, 32))
+        #print "INITIAL: " + str(initialReturn)
+
+        for i in range(33, 127):
+            message2 = message1 + secret + chr(i)
+            s.sendall(message2)
+            data = s.recv(8192)
+            oracle = list(chunkstring(data, 32))
+            #print "ORACLE: " + str(oracle)
+            compareBlock = (len(message2) / 16)
+            #print "COMPARE = " + str(compareBlock)
+            if oracle[compareBlock] == initialReturn[compareBlock]:
+                secret += chr(i)
+                #print "LENGTH: " + str(len(secret))
+                #print "SECRET: " + secret
+                #print "INITIAL: " + str(initialReturn)
+                #print "ORACLE: " + str(oracle)
+                if len(secret) == secretLen:
+                    found = True
+                    print secret
+                break
+
+finally:
+    s.close()

ECBPlaintextAttack/ecbServer.py

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+#!/usr/bin/python
+
+from Crypto.Cipher import AES
+import socket
+import sys
+import random
+import string
+
+blockSize = 16
+encKey = "ENCRYPTIONKEY123"
+#secret = "mys3cretP@ssword!"
+before = ""
+#before = "ENCRYPT:"
+chars = string.ascii_letters + string.digits + string.punctuation
+secret = ''.join(random.choice(chars) for _ in range(random.randint(1,1000)))
+
+def pad(input):
+	if (len(input) % blockSize == 0):
+		return input
+	else:
+		extra = blockSize - (len(input) % blockSize)
+		output = input + "\x00" * extra
+		return output
+
+def unpad(input):
+	return input.rstrip("\x00")
+
+def encrypt(input):
+	if (input is None) or (len(input) == 0):
+		print "Input text cannot be null or empty"
+
+	input += secret
+	input = pad(before + input)
+	cipher = AES.AESCipher(encKey, AES.MODE_ECB)
+	cipherText = cipher.encrypt(input)
+	return cipherText.encode("hex")
+
+def decrypt(input):
+	if (input is None) or (len(input) == 0):
+		print "Input text cannot be null or empty"
+
+	encrypted = input.decode("hex")
+	cipher = AES.AESCipher(encKey, AES.MODE_ECB)
+	plainText = unpad(cipher.decrypt(encrypted))
+	return plainText
+
+def main():
+	print "SECRET LENGTH: " + str(len(secret))
+	print "SECRET = " + secret
+
+	s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+	s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+
+	server_address = ('localhost', 10000)
+	print "\nStarting up on %s port %s" % server_address
+	s.bind(server_address)
+
+	s.listen(1)
+
+	while True:
+	   	connection, client_address = s.accept()
+
+	   	try:
+	   		while True:
+	   			data = connection.recv(2048)
+	   			if data:
+	   				#print "DATA: " + data
+	   				input = data.rstrip()
+	   				print "INPUT: " + input
+	   				print "HEX: " + input.encode("hex")
+	   				encrypted = encrypt(input)
+	   				print "ENCRYPTED: " + encrypted
+	   				connection.send(encrypted)
+	   			else:
+	   				break
+	   	finally:
+	   		connection.close()
+
+if __name__ == "__main__":
+    main()