Let's suppose I want to encrypt my disk partition with AES-256 in CTR mode 2 times using two different keys and IVs.
Will I get 512 bits of encryption strength?
Asked
Active
Viewed 126 times
1
-
You are correct, the 1D-meet-in-the-middle attack applies. If you have four or more matched plain and cipher blocks, you have a good chance of uniquely identifying the key without additional testing. Thus the overall complexity will be a little over 256-bits. Note that the memory requirements are much bigger than for exhaustive attacks. – Daniel S Apr 16 '21 at 06:23
-
Why do you need 512-bit encryption? – kelalaka Apr 18 '21 at 17:48
-
@kelalaka -- I'm too paranoid and I want to keep my encryption safe against quantum computers. – phantomcraft Apr 20 '21 at 00:21
-
Use 256-bit key size then you are safe : Has AES-128 been fully broken? – kelalaka Apr 20 '21 at 00:23
-
@DanielS CTR doesn't have decryption process, I still believe that multiple encryption with CTR mode is immune to MITM attacks. – phantomcraft Jan 23 '22 at 03:16