# CPRNG-AES

This module provides a crypto pseudo random number generator using AES in counter mode.

to import:

```
import Crypto.Random.AESCtr
```

to use:

```
rng <- makeSystem
let (ran, rng') = getRandomBytes rng 1024
```

itâ€™s also an instance of CryptoRandomGen from the crypto-api package.

## Statistics

Using ent, a randomness property maker on one 1Mb sample.

cprng-AES:

```
Entropy = 7.999837 bits per byte.
Optimum compression would reduce the size of this 1048576 byte file by 0 percent.
Chi square distribution for 1048576 samples is 237.02.
Arithmetic mean value of data bytes is 127.3422 (127.5 = random).
Monte Carlo value for Pi is 3.143589568 (error 0.06 percent).
```

Compared to urandom with the same sampling:

```
Entropy = 7.999831 bits per byte.
Optimum compression would reduce the size of this 1048576 byte file by 0 percent.
Chi square distribution for 1048576 samples is 246.63.
Arithmetic mean value of data bytes is 127.6347 (127.5 = random).
Monte Carlo value for Pi is 3.132465868 (error 0.29 percent).
```