This use case does not work

[shijimasoft]

I open this issue because I ran into a somewhat strange situation: I am rewriting a python code in rust using libaes for AES decryption, below is the code I use:

    let data: [u8; 16] = hex!("9f2707bc98bb5781d4e7b461bffe6270");
    let key: [u8; 16] = hex!("64c5fd55dd3ad988325baaec5243db98");
    let iv: [u8; 16] = hex!("0004008c001658000000000000000000");

    let aes: Cipher = Cipher::new_128(&key);
    let dec: Vec<u8> = aes.cbc_decrypt(&iv, &data);

    println!("{:?}", dec); // This will print an empty vec

Using pycrypto instead works correctly, returning the expected result: 59f96218d8eccab277ed477a33dcb7f3 (expected byte array translated into an hex string)

Maybe I'm doing something wrong or just forgetting some padding things or the data format is incorrect (literal hex! returns a decimal format byte array i.e: [159, 39, 7, 188, 152, 187, 87, 129, 212, 231, 180, 97, 191, 254, 98, 112])

[shijimasoft]

I tried the reverse (encryption) process and the data I got are slightly different from what I expected in fact the encrypted data are: 9f2707bc98bb5781d4e7b461bffe6270b419f11edb920f94f6a1b6ec8e469926 (32 bytes) and not the expected 9f2707bc98bb5781d4e7b461bffe6270 (16 bytes).

[keepsimple1]

This is because padding (PKCS7) is always included, hence for a 16-byte input, its padding will be another 16-byte padding, leading to total 32 bytes.

pycrypto is different in a way that padding is handled separately and require the user to add padding when needed.

[shijimasoft]

Is it possible to implement a flag for manual padding management? (For encryption as well as decryption)

[keepsimple1]

Is it possible to implement a flag for manual padding management? (For encryption as well as decryption)

Yes it's possible. I've opened a PR #30 to do that. Would you have time to try out the PR's branch and see it works for you?

[shijimasoft]

I just checked the PR, everything seems to be working correctly (I also tried other use cases and they are all correct). Thank you for being so quick to help me!

[keepsimple1]

Thanks for verifying! I've merged the PR. Will post a new release soon.

[shijimasoft]

Okk! Thank you for your work!