WannaCry in-memory key recovery for Windows XP

Re:WannaCry in-memory key recovery for Windows XP by kutkloon7 on Saturday May 20, 2017 @06:52AM (#14381801)

What is the fundamental difference? The pitfall that makes it possible to decrypt is that the key which is needed to decrypt is not cleared from memory. Your proposed strategy has exactly the same problem.

What would work is hardcoding a large number of public keys in the binary. Then upon paying the ransom the attacker could give the private key to the victim.

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Re:WannaCry in-memory key recovery for Windows XP by roblabla on Saturday May 20, 2017 @07:03AM (#14381835)

That is not how async crypto works. If you only provide the public key (as opposed to creating a keypair locally) you could print it out to the victim and it wouldn't matter, as it can only be used to encrypt.

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Re:WannaCry in-memory key recovery for Windows XP by kutkloon7 on Saturday May 20, 2017 @08:42AM (#14382124)

Which is exactly my point. Ideally, you want to encrypt with a key that is different from the key that you need to decrypt, so that you can encrypt without ever having the key that is needed to decrypt in memory. This is impossible with symmetric cryptography.

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Re:WannaCry in-memory key recovery for Windows XP by paulddraper on Sunday May 21, 2017 @12:01PM (#14387838)

You're right. On the other hand, asymetric encryption if a disk will be dog slow.

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