Stream deniable-encryption computationally indistinguishable from probabilistic ciphering

For the first time it is proposed a stream deniable-encryption algorithm. The algorithm generates cryptogram that is computationally indistinguishable from the cryptogram produced by some probabilistic encryption algorithm, called associated probabilistic algorithm, while ciphering a fake message with a fake key. When the sender and receiver of the message are coerced to open the encryption key, they open the fake key with which the cryptogram is transformed into the fake message. To recover the secret message from the cryptogram the receiver uses the secret key. The algorithm is constructed on the base of some secure hash function with which two key streams are generated. The key streams are mixed with secret data stream and with fake data stream so that cryptograms looks like the ciphertext produced by the probabilistic encryption of the fake message with the fake key.