Amazon.com, Inc.
Data encryption method and system

Abstract:

Plaintext data is encrypted and decrypted using a symmetric encryption algorithm that generates a sequence of pseudorandom values from a cryptographic key. A portion of the sequence of pseudorandom values is discarded. For example, in an embodiment, each value in the sequence of pseudorandom values is truncated by a number of bits. Encryption and decryption is performed by combining plaintext or ciphertext with the truncated sequence of pseudorandom values. In an embodiment, the combination is made by performing a bitwise exclusive or operation between the truncated pseudorandom values and the plaintext or ciphertext. In an embodiment, a number of bits discarded from each value is encoded into a message authentication code which is provided with any resulting ciphertext.