[Cryptography] [FORGED] Re: Crypto best practices

[Patrick Chkoreff]

I wrote:

> 1. Generate an unpredictable IV.
> 
> 2. Encrypt the IV with AES-ECB and send that as the first block.
> 
> 3. For each block of data, XOR it with the IV and encrypt that result
> with AES-ECB.

It was brought to my attention, offlist, that this reveals when two
plaintext blocks are equal.  Thanks for that.  That's exactly the sort
of "obvious in hindsight" observation I wanted to hear.

So I amend it to:

3. For each block of data, XOR it with the IV, add the sequential block
index, and encrypt that result with AES-ECB.


-- Patrick