Problem: Trying to create a new encrypted message with the same cocoon object generates the same ciphertext. It mostly affects MiniCocoon
and Cocoon
objects with custom seeds and RNGs (where StdRng
is used under the hood).
Note: The issue does NOT affect objects created with Cocoon::new
which utilizes ThreadRng
.
Cause: StdRng
produces the same nonce because StdRng::clone
resets its state.
Measure: Make encryption API mutable (encrypt
, wrap
, and dump
).
Workaround: Create a new cocoon object with a new seed per each encryption.
let cocoon = MiniCocoon::from_password(b"password", &[1; 32]);
let mut data1 = "my secret data".to_owned().into_bytes();
let _ = cocoon.encrypt(&mut data1)?;
let mut data2 = "my secret data".to_owned().into_bytes();
let _ = cocoon.encrypt(&mut data2)?;
// data1: [23, 217, 251, 151, 179, 62, 85, 15, 253, 92, 192, 112, 200, 52]
// data2: [23, 217, 251, 151, 179, 62, 85, 15, 253, 92, 192, 112, 200, 52]
For cocoon <= 0.3.3
, create a new cocoon with a different seed per each encrypt
/wrap
/dump
call.
let cocoon = MiniCocoon::from_password(b"password", &[1; 32]);
let mut data1 = "my secret data".to_owned().into_bytes();
let _ = cocoon.encrypt(&mut data1)?;
// Another seed: &[2; 32].
let cocoon = MiniCocoon::from_password(b"password", &[2; 32]);
let mut data2 = "my secret data".to_owned().into_bytes();
let _ = cocoon.encrypt(&mut data2)?;
// data1: [23, 217, 251, 151, 179, 62, 85, 15, 253, 92, 192, 112, 200, 52]
// data2: [53, 223, 209, 96, 130, 99, 209, 108, 83, 189, 123, 81, 19, 1]