Abstract: The method generally includes the steps of receiving (201) a message (100) comprising a message indicator (101) and a plurality of encrypted blocks (103 through 111). When at least one block of the plurality of encrypted blocks is received with error, a second message is transmitted (215), which second message requests a retransmission of the at least one block. Upon receiving the retransmission of the at least one block without error, a keystream is generated (219) from the message indicator and the at least one block is decrypted using the keystream.

Abstract: A method of decrypting retransmitted parts of a message includes receiving (201) a message comprising encryption synchronization and a plurality of encrypted blocks. Until a first block of the plurality of encrypted blocks is received with error, a first keystream is generated (205) from the encryption synchronization and at least one of the plurality of encrypted blocks, and, using the first keystream, the plurality of encrypted blocks, received without error before the first block of the plurality of encrypted blocks is received with error, is decrypted (207). A priming block is determined (211) from the message. When the first block of the plurality of encrypted blocks is received with error, a second message is transmitted (219) requesting a retransmission of the first block.

Abstract: In a receiver (100), an encrypted communication (104) is decrypted using a decryptor (101) and a key (107) to produce a decrypted communication (105). A comparator (103) compares decrypted symbol patterns in the decrypted communication against a set of predetermined symbol patterns (108). When the decrypted symbol patterns are distributed non-uniformly relative to the set of predetermined symbol patterns, the receiver is identified as a target of the encrypted communication.