Is AES-128 still safe to use?

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Harry

Member
Oct 13, 2020
17
7
There's an interesting note in the CISA SolarWinds incident response recommendations:

"Set account options for service accounts to support AES256_CTS_HMAC_SHA1_96 and not support DES, RC4, or AES128 bit encryption"


Is CISA suggesting that AES-128 is no longer secure? I understand that people should choose the most secure encryption reasonably possible, but that's different than instructing people to not support something. I hope this isn't one of those cases where CISA knows something and aren't telling us yet. A more conspiratorial view is that the US government knows a foreign adversary has cracked AES-128. I think that's unlikely, but possible.
 

PHolder

Well-known member
Sep 16, 2020
724
2
356
Ontario, Canada
Well according to https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-57pt1r5.pdf (look for 5.6.3 Projected Security Strength Time Frames and Current Approval Status) 128bit is still permitted for use up until 2030. I suspect if there is any concern, it is related to the progress of quantum computers and the worry they might significantly reduce the strength of algorithms not specifically hardened again quantum computing.
 

Harry

Member
Oct 13, 2020
17
7
Well according to https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-57pt1r5.pdf (look for 5.6.3 Projected Security Strength Time Frames and Current Approval Status) 128bit is still permitted for use up until 2030. I suspect if there is any concern, it is related to the progress of quantum computers and the worry they might significantly reduce the strength of algorithms not specifically hardened again quantum computing.
That may be the case, but has CISA given this advice anywhere else? It seems like it is in the context of the SolarWinds situation.