76 lines
2 KiB
Python
76 lines
2 KiB
Python
import os
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from cryptography.hazmat.primitives.ciphers.aead import AESGCM
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import argparse
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def setup(key_file):
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key = AESGCM.generate_key(bit_length=128)
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with open(key_file, "wb") as f:
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f.write(key)
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def encrypt(input_file, key_file):
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with open(input_file, "rb") as f:
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plaintext = f.read()
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with open(key_file, "rb") as f:
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key = f.read()
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aad = b"authenticated but unencrypted data"
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aesgcm = AESGCM(key)
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nonce = os.urandom(12)
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ct = aesgcm.encrypt(nonce, plaintext, aad)
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with open(f"{input_file}.enc", "wb") as f:
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f.write(nonce)
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f.write(ct)
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def decrypt(input_file, key_file):
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with open(input_file, "rb") as f:
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nonce = f.read(12)
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ct = f.read()
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with open(key_file, "rb") as f:
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key = f.read()
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aad = b"authenticated but unencrypted data"
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aesgcm = AESGCM(key)
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pt = aesgcm.decrypt(nonce, ct, aad)
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with open(f"{input_file}.dec", "wb") as f:
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f.write(pt)
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def main():
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parser = argparse.ArgumentParser(
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description="Program to perform operations using AES-GCM cipher on files",
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)
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subparsers = parser.add_subparsers(dest="operation", help="Operation to perform")
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# Encrypt subcommand
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enc_parser = subparsers.add_parser("enc", help="Encrypt a file")
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enc_parser.add_argument("fich", help="File to be encrypted")
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enc_parser.add_argument("password", help="Pass-phrase to derive the key")
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# Decrypt subcommand
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dec_parser = subparsers.add_parser("dec", help="Decrypt a file")
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dec_parser.add_argument("fich", help="File to be decrypted")
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dec_parser.add_argument("password", help="Pass-phrase to derive the key")
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args = parser.parse_args()
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match args.operation:
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case "enc":
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input_file = args.fich
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password = args.password
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encrypt(input_file,password)
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case "dec":
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input_file = args.fich
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password = args.password
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decrypt(input_file,password)
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if __name__ == "__main__":
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main()
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