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From: Stefan Claas <pollux@tilde.club>
Newsgroups: sci.crypt
Subject: XChaCha20 Python3 CLI tool
Date: Sun, 8 Sep 2024 17:31:34 -0000
Organization: Ch1ffr3punk5
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Hi all,

DJB's XChaCha20 stream cipher is pretty cool for Text messages (SMS),
if you have also a proper encoder for the binary output.

So I decided to convert my Go Code to Python3.

Here is the program to play with, base64 encoded.

$ ./xchacha20.py
Error: Incorrect number of arguments
Usage: ./xchacha20.py <keyfile> <noncefile> < infile > outfile

XChaCha20 encryption/decryption tool

Arguments:
  keyfile    Path to the file containing the key in hexadecimal format
  noncefile  Path to the file containing the nonce in hexadecimal format

The program reads from stdin and writes to stdout. Use input/output redirection for files.

Examples:
  Encryption: ./xchacha20.py key.hex nonce.hex < plaintext.txt > encrypted.bin
  Decryption: ./xchacha20.py key.hex nonce.hex < encrypted.bin > decrypted.txt

Note: The key should be 32 hex bytes (64 characters) long.
      The nonce should be 24 hex bytes (48 characters) long.

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$ openssl rand -hex 32 > key
$ openssl rand -hex 24 > nonce
$ echo -n 'Hello World!' | xchacha20 key nonce | hexdump -Cv
00000000  01 eb 7f 2e d5 e9 a4 e0  c8 e4 e2 d6 |............|
0000000c

-- 
Regards
Stefan