Logic in streaming decryption isn't quite right

[itamarst]

In particular, at https://github.com/skerkour/kerkour.com/blob/main/2021/rust_file_encryption/src/main.rs#L147, if original file size was exactly multiple of 500, the code won't identify the last chunk correctly.

Thanks for your helpful articles!

[sylvain101010]

Good catch, it's now fixed :)