Cryptographic device and method for generating pseudo-random numbers
AssigneeFrance Telecom
InventorMatt Robshaw
Life of this patent
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Abstract
A cryptographic device and a cryptographic method of generating pseudo-random numbers. Initial data is divided into a plurality of words on b bits defined in a finite body GF(2b). The words are assigned to cells of a state table to form an initial state block. The cells of the state table are grouped to assign a group of cells to each set of d/b words, where d is a multiple of b strictly greater than b. And, a succession of state blocks is iteratively generated from the initial state block to form a final state block, so that on each iteration each set of d/b words of a current state block is replaced by another set of d/b words to form a next state block using a reference table including substitution elements on d bits.
Claims11
1-10. (canceled)
A cryptographic method of generating pseudo-random numbers, comprising:
- dividing initial data into a plurality of words on b bits defined in a finite body GF(2b);
- assigning the words to cells of a state table to form an initial state block;
- grouping the cells of the state table to assign a group of cells to each set of d/b words, wherein d is a multiple of b strictly greater than b;
- and
- generating a succession of state blocks iteratively from the initial state block to form a final state block representative of a pseudo-random number, so that on each iteration each set of d/b words of a current state block is replaced by another set of d/b words to form a next state block using a reference table including substitution elements on d bits.
A cryptographic device for generating pseudo-random numbers, comprising:
- division means for dividing initial data into a plurality of words on b bits defined in a finite body GF(2b);
- assignment means for assigning the words to cells of a state table to form an initial state block;
- definition means for defining and storing a reference table including substitution elements on d bits where d is a multiple of b strictly greater than b;
- grouping means for grouping the cells of the state table to assign a group of cells to each set of d/b words;
- and
- generating means for generating a succession of state blocks iteratively from the initial state block to form a final state block, so that on each iteration each set of d/b words of a current state block is replaced by another set of d/b words as a function of a reference table to form a next state block.
Dependencies are inferred from the claim text.