implementacao em piton

TPs/TP02/py/cfich_chacha20.py

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+#!/usr/bin/env python3
+
+from cryptography.hazmat.primitives.ciphers import Cipher, algorithms
+import sys
+import os
+
+def setup(key_file):
+    f = open(key_file,"wb")
+    key_bytes = os.urandom(32)
+    f.write(key_bytes)
+    f.close()
+
+def encrypt(input_file, key_file):
+    fkey = open(key_file,"rb")
+    inp = open(input_file,"rb")
+    out = open(f"{input_file}.enc","wb")
+
+    key = fkey.read()
+    plaintext = inp.read()
+    nonce = os.urandom(16)
+    cipher = Cipher(algorithms.ChaCha20(key=key,nonce=nonce),mode=None)
+    encryptor = cipher.encryptor()
+    ciphertext = encryptor.update(plaintext)
+    ciphertext = nonce + ciphertext
+
+    out.write(ciphertext)
+
+    fkey.close()
+    inp.close()
+    out.close()
+
+def decrypt(input_file,key_file):
+    fkey = open(key_file,"rb")
+    inp = open(f"{input_file}.enc","rb")
+    out = open(f"{input_file}.dec","wb")
+
+    key = fkey.read()
+    input_bytes = inp.read()
+    nonce = input_bytes[:16]
+    ciphertext = input_bytes[16:]
+
+    cipher = Cipher(algorithms.ChaCha20(key=key,nonce=nonce),mode=None)
+    decryptor = cipher.decryptor()
+    plaintext = decryptor.update(ciphertext)
+
+    out.write(plaintext)
+
+    fkey.close()
+    inp.close()
+    out.close()
+
+def main():
+    args = sys.argv[1:]
+    if len(args) == 0:
+        sys.exit("Needs at least 2 arguments, use help.")
+
+    match args[0]:
+        case "setup":
+            if len(args) != 2:
+                print("Number of arguments is incorrect for setup option")
+            key_file = args[1]
+            setup(key_file)
+        case "enc":
+            if len(args) != 3:
+                print("Number of arguments is incorrect for enc option")
+            input_file = args[1]
+            key_file = args[2]
+            encrypt(input_file,key_file)
+        case "dec":
+            if len(args) != 3:
+                print("Number of arguments is incorrect for dec option")
+            input_file = args[1]
+            key_file = args[2]
+            decrypt(input_file,key_file)
+
+        case "help":
+            print("skill issue")
+        case _:
+            print(f"{args[1]} is not an option, use help")
+
+if __name__ == "__main__":
+    main()

TPs/TP02/py/input.txt

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+panda é fixe!!!

TPs/TP02/py/input.txt.dec

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+panda é fixe!!!

TPs/TP02/py/input.txt.enc

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+…[nÍ"[v©Õ·µ4ZÍ![n{V­ƒ#<23>ÿì<C3BF>»

TPs/TP02/py/key

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+ן<EFBFBD>Y!ֽ¬m›½'•HjS‘ע<E28098><ה<>:לְAֶ‡Ff