Deniable Encryption

In cryptography and steganography, plausibly deniable encryption is encryption that allows its users to convincingly deny that some specific encrypted data exists, that a given piece of data is encrypted, or that they are able to decrypt a given piece of encrypted data. Such denials may or may not be genuine. For example, although suspicions might exist that the data is encrypted, it may be impossible to prove it without the cooperation of the users. If the data is encrypted, the users genuinely may not be able to decrypt it. Deniable encryption serves to undermine an attacker's confidence either that data is encrypted, or that the person in possession of it can decrypt it and provide the associated plaintext.

Normally ciphertexts decrypt to a single plaintext and hence once decrypted, the encryption user cannot claim that he encrypted a different message. Deniable encryption allows its users to decrypt the ciphertext to produce a different (innocuous but plausible) plaintext and insist that it is what they encrypted. The holder of the ciphertext will not have the means to differentiate between the true plaintext, and the bogus-claim plaintext.