Is it possible to find data which makes sense when decrypted with different keys?

Question

In theory, does a piece of data exist which, when encrypted (using any method) with a given key, makes some sense when decrypted with the wrong key?

Here, a definition of "some sense" might be something like "when interpreted as ASCII character codes, the data forms a series of mostly correctly spelled English words". In essence, a definition of "some sense" would be that the decrypted data looks (almost) like it was correctly decrypted.

You may be interested in honey encryption. – DrLecter May 19 '14 at 10:15 — DrLecter, May 19 '14 at 10:15
That sounds like exactly what I wondering about! Thanks. – AndyBursh May 19 '14 at 10:26 — AndyBursh, May 19 '14 at 10:26

score 2 · Accepted Answer · answered May 19 '14 at 11:25

2

Yes. How to find such data depends on which encryption you are using. With one time pads it's trivial: You can freely choose another pad that when used as a key will decrypt the ciphertext to an arbitrary message (of proper length).

answered May 19 '14 at 11:25

otus

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score 2 · Answer 2 · answered May 20 '14 at 11:06

Yes, it is possible. Try to decrypt the one-time-pad cyphertext f54bfe292ad6c2dba0def4e80c0a63c9e562597cfe30 with these 2 keys:

bc6b904c4fb2e2a2cfab86c8646f0fb9c9423d099a55 b92e8a0947b3e2b3c5b284c8756516e5c530361b9b42

In the first case you will get 'I need your help, dude', in the second case you will get 'Let me help you, Roger'.

score 0 · Answer 3 · answered May 20 '14 at 12:08

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If you know the plaintext space then it makes sense. If for instance you know that encrypted values are encoded digits and you are decrypting noise data then you can verify the correctness of decryption

answered May 20 '14 at 12:08

curious

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Is it possible to find data which makes sense when decrypted with different keys?

3 Answers3

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