Limiting delays associated with the generation of

专利名称：Limiting delays associated with the

generation of encryption stream ciphers

发明人：Gregory G. Rose,Roy Franklin Quick, Jr.申请号：US09246366申请日：19990208公开号：US06560338B1公开日：20030506

专利附图：

摘要：A method and an apparatus for generating encryption stream ciphers are basedon a recurrence relation designed to operate over finite fields larger than GF(2). A non-linear output can be obtained by using one or a combination of non-linear processes to

form an output function. The recurrence relation and the output function can be selectedto have distinct pair distances such that, as the shift register is shifted, no identical pair ofelements of the shift register are used twice in either the recurrence relation or theoutput function. Under these conditions, the recurrence relation and the output functionalso can be chosen to optimize cryptographic security or computational efficiency.Moreover, it is another object of the present invention to provide a method of assuringthat the delay that results for the encryption process does not exceed predeterminedbounds. To this end the ciphering delay is measured and if the estimated delay exceeds apredetermined threshold a second ciphering method is employed to limit theaccumulated delay of the ciphering operation.

申请人：QUALCOMM INCORPORATED

代理人：Philip R Wadsworth,Charles D. Brown,Kyong H. Macek

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