chacha20poly1305 decode issue

[vorcigernix]

This is probably my code, I copy pasted the decode function from the internet (my cryptography knowledge is basic). Code looks like this:

fn decrypt(obsf: &[u8], key: &[u8]) -> String {
    type NonceSize = <ChaCha20Poly1305 as AeadCore>::NonceSize;
    let cipher = ChaCha20Poly1305::new(GenericArray::from_slice(key));
    let (nonce, ciphertext) = obsf.split_at(NonceSize::to_usize());
    let nonce = GenericArray::from_slice(nonce);
    let plaintext = match cipher.decrypt(nonce, ciphertext) {
        Ok(v) => v,
        Err(e) => {
            println!("Decryption failed: {:?}", e);
            return e.to_string();
        }
    };
    String::from_utf8(plaintext).unwrap()
}

and obsf/key seems to be correct vectors, example:

[12, 140, 198, 139, 82, 101, 80, 102, 13, 101, 156, 164, 50, 27, 12, 209, 228, 160, 3, 135, 141, 230, 200, 213, 230, 106, 209, 189, 41, 82, 146, 42]
[91, 50, 50, 56, 44, 49, 48, 54, 44, 50, 48, 57, 44, 57, 53, 44, 50, 48, 49, 44, 49, 50, 52, 44, 49, 52, 52, 44, 49, 57, 52, 44, 51, 51, 44, 53, 55, 44, 54, 53, 44, 49, 49, 52, 44, 57, 49, 44, 49, 55, 53, 44, 49, 48, 49, 44, 49, 56, 53, 44, 50, 48, 56, 44, 50, 50, 52, 44, 50, 49, 49, 44, 50, 49, 52, 44, 49, 53, 48, 44, 50, 50, 44, 50, 49, 56, 44, 49, 50, 44, 50, 55, 44, 50, 56, 44, 50, 50, 55, 44, 54, 55, 44, 50, 51, 55, 44, 53, 56, 44, 50, 49, 50, 44, 49, 57, 51, 44, 50, 52, 44, 50, 48, 48, 44, 49, 57, 53, 44, 50, 53, 50, 44, 51, 55, 93]

Any idea what could be wrong? Whole code is here: https://github.com/vorcigernix/tokenshare/blob/main/src/app.rs

[vorcigernix]

So I tried a lot of things, code looks very different, but the issue persists. I am printing input and output and they look exactly the same, but the decode function fails. Any help would be really appreciated.

[newpavlov]

I am not sure what exactly is your problem. Have you verified that you get the same key/nonce/ciphertext? Try to minimize your problem. It's likely that you have a problem not with cryptography per se, but with something else in your code. It's probably better to ask such questions on the URLO forum.