I want to encrypt my pagefile.sys. I do not need to access information from it, so I don't need the encryption key after restart. I have these four alternatives:

  1. AES-256 key in Cipher Block Chaining (CBC) mode
  2. Blowfish-448 key CBC mode
  3. Gost-256 key in Cipher Feedback Mode (CFB)
  4. Twofish-256 key CBC.

So which is the best choice? I dug on Google, and my opinion is 4. Expert opinion?


2 Answers 2


Encrypting the pagefile implies you're wanting to protect against someone taking the file after gaining physical access, which is best dealt with by whole disk encryption. If an attacker has access while the os is in operation, the pagefile is neat to go through for historical purposes but otherwise juicier targets abound. If the purpose is to clean tracks after having used a ton of ram, then you're better off using a cleaner tool of some sort (yeah that's vague, you figure it out) to selectively edit/overwrite.


Those are all secure choices with regards to the algorithm. AES has a 16 byte block size and has been the most scrutinized (as Rijndael won the AES competition). It's also most likely to be well optimized or implemented in hardware. So that's why it should generally be the preferred option.

  • PS I'm presuming here that these alternatives are provided by the OS. If not you may want to rethink your strategy. In other words, the above answer is just about the choice of algorithm, nothing else. Jun 17, 2015 at 22:18

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