[Cryptography] Crypto best practices

[Hanno Böck]

On Tue, 7 Mar 2017 17:59:16 -0500
Patrick Chkoreff <patrick at rayservers.net> wrote:

> This looks like some very valuable advice:
> 
> https://wikileaks.org/ciav7p1/cms/files/NOD%20Cryptographic%20Requirements%20v1.1%20TOP%20SECRET.pdf
> 
> Excerpt:
> 
> > Key exchange must be performed using Diffie-Hellman, Elliptic Curve
> > Diffie-Hellman, or RSA. For Elliptic Curve Diffie-Hellman the prime
> > moduli utilized must be at least 256 bits. For Diffie- Hellman and
> > RSA the primes utilized must be at least 2048 bits. The use of
> > Diffie-Hellman or Elliptic Curve Diffie-Hellman is recommended to
> > allow for perfect forward secrecy.  
> ...
> > Confidentiality must be provided by AES with a minimum key size of
> > 256 bits. The cipher must be operated in Galois/Counter Mode (GCM),
> > Counter Mode (CTR), or Cipher Block Chaining Mode (CBC).  

That's already bad advice. Use an AEAD, always. From the mentioned ones
only CTR is an AEAD.

If you read through the whole document it's long and contains a lot of
strange advice, including recommendations for RC4 + countermeasures
that we know don't properly work. It's full of recommendations that I'd
name outdated.

There's also some good advice in there, but none of it is surprising.

-- 
Hanno Böck
https://hboeck.de/

mail/jabber: hanno at hboeck.de
GPG: FE73757FA60E4E21B937579FA5880072BBB51E42