[LABI] tema01: added cipher_ARC4.py

1ano/2semestre/labi/tema01/src/cipher_ARC4.py

@@ -0,0 +1,32 @@
+import sys
+import hashlib
+from Crypto.Cipher import ARC4
+
+
+def generate_key(key):
+    if len(key) < 5:
+        # Gerar uma síntese de chave com SHA-256
+        key = hashlib.sha256(key.encode('utf-8')).digest()
+    elif len(key) > 256:
+        # Usar apenas os primeiros 256 octetos
+        key = key[:256].encode('utf-8')
+    else:
+        key = key.encode('utf-8')
+    return key
+
+
+def encrypt_file(file_path, key):
+    with open(file_path, 'rb') as file:
+        data = file.read()
+    cipher = ARC4.new(generate_key(key))
+    ciphertext = cipher.encrypt(data)
+    sys.stdout.buffer.write(ciphertext)
+
+
+if __name__ == '__main__':
+    if len(sys.argv) != 3:
+        print('Usage: python3 Ex4.py file key > file_to_send_encriptation', file=sys.stderr)
+        sys.exit(1)
+    file_path = sys.argv[1]
+    key = sys.argv[2]
+    encrypt_file(file_path, key)