Re: Byte Addressability And Beyond

On Tue, 4 Jun 2024 02:00:55 -0000 (UTC), Lawrence D'Oliveiro
<ldo@nz.invalid> wrote:

On Mon, 3 Jun 2024 17:42:17 +0300, Michael S wrote:
>

On Mon, 03 Jun 2024 14:07:12 GMT scott@slp53.sl.home (Scott Lurndal)
wrote:
 

Most modern CPUs have instruction set support for symmetric ciphers
such as AES, SM2/SM3 as well as message digest/hash (SHA1, SHA256 et
al).
 

It is still not *too* fast.
'Too fast' in my book is when with 1B to 10B USD worth of OTP servers
you can break cipher by brute force in less than 1 hour.

>
The good algorithms are designed to be fast for encryption/decryption use,
while still being uselessly slow for cracking purposes.
>
Hash algorithms come in two flavours: cryptographic hashes (as mentioned
above) and password hashes. Cryptographic hashes have to be fast to
compute, but password hashes should take some appreciable fraction of a
second. This is fast enough to authenticate a user logging in, while
significantly slowing down password-guessing attacks.
>
For example, the WordPress password-hashing algorithm takes a
cryptographic hash like MD5 (considered crap nowadays), and iterates it
8000 times. And suddenly crap becomes good.

It's debatable whether repeated application of a given function really
represents a /different/ function.

In any event there is no such thing as a "password" hash - really
there only are cryptographic hashes.  A use of a particular hash for
passwords may deliberately slow its execution - e.g., by iterating or
by deliberate delays - but the hash algorithm remains the same.