| 摘要 |
An encryption/decryption method and apparatus may comprise performing in series stages of encryption/decryption operations on a stage data block of a first selected width utilizing an encryption/decryption key of the first selected width and providing an output data block of the first selected width, comprising a subsequent stage input data block input to a subsequent stage of the series of stages; holding the stage input data block for input into a stage of the series of stages, the input data block having the first selected width; encrypting the stage input data block into a encrypted stage input data block having the first selected width, the encrypted stage input data block comprising a unique combination of data bits for each unique combination of data bits in the stage input data block of the first selected width; decrypting the stage input data block into a decrypted stage input data block having the first selected width, the decrypted stage input data block comprising a unique combination of data bits for each unique combination of data bits in the stage input data block of the first selected width that is the inverse of the encryption performed by the encryption step; performing a substitution operation on either the encrypted stage input data block or the decrypted stage input data block. A subsequent stage input data block may be the subsequent stage of the series of stages the output of the substitution step or the stage input data block. One may perform in series the stages of the encryption/decryption operations in a first plurality of stages of the series of stages, each comprising a round, and repeat this operation a selected number of times and a selected number of rounds each of the selected number of times, to thereby effect a total number of rounds. One may perform in any given one of the first plurality of times less than the first plurality of rounds depending upon the total number of rounds necessary. One may generate each round key by the expansion of a starting key of a second selected width. The second selected width may equal the first selected width; and, the encryption step may further include performing an affine transformation and the decryption step may further include performing an inverse of the affine transformation.
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