Patent ID: 8687800

Claim:
A method for message encryption, comprising: deriving, by a processor, a first key (K 1 ) and a second key (K 2 ) from a session key; generating, by the processor, a first pseudorandom string of bits as a function of K 1 using a first-cipher algorithm; generating, by the processor, a second pseudorandom string of bits as a function of K 1 using the first cipher algorithm, wherein a state of randomization of said first pseudorandom string is independent of a state of randomization of said second pseudorandom string; encrypting a first block of message data with the first pseudorandom string, the encrypting comprising performing a reversible XOR operation between each of at least some bits of the first block and each of respective bits of the first pseudorandom string; encrypting a successive second block of message data with the second pseudorandom string, the encryption comprising performing a reversible XOR operation between each of at least some bits of the second block and each of respective bits of the second pseudorandom string; producing an encrypted message by encrypting the first and second encrypted blocks of message data using a second cipher algorithm that takes K 2 as an input key; and transmitting the encrypted message.