Method and apparatus for encrypting data in a wireless communication system

Abstract

In a communications system, a method of transforming a set of message signals representing a message comprising the steps of first encoding one of the set of message signals in accordance with a first keyed transformation, a second encoding of the one of the set of message signals in accordance with at least one additional keyed transformation, a third encoding of the one of the set of message signals in accordance with a self inverting transformation in which at least one of the set of message signals is altered, a fourth encoding of the one of the set of message signals in accordance with at least one additional inverse keyed transformation wherein each of the at least one additional inverse keyed transformation is a corresponding inverse of at least one additional keyed transformation, and fifth encoding the one of the set of message signals in accordance with first inverse keyed transformation wherein the first inverse keyed transformation is the inverse of the first keyed transformation.

1 . A method for encrypting data, the method comprising:
 first encoding the data in accordance with a keyed transformation; and   second encoding the first encoded data;   wherein the first keyed transformation comprising selecting an entry from a first table in accordance with a first index and wherein the first table has no entry equal to its corresponding index.   
     
     
         2 . The method of  claim 1 , wherein the first keyed transformation is a non-linear transformation. 
     
     
         3 . The method of  claim 1 , wherein the second encoding comprises encoding in accordance with a second keyed transformation, and wherein the second keyed transformation comprises selecting an entry from a second table in accordance with a second index and wherein the second table has no entry equal to its corresponding index. 
     
     
         4 . The method of  claim 3 , further comprising third, fourth, fifth and sixths encodings. 
     
     
         5 . The method of  claim 1 , wherein at least one of the first index and second index is a portion of a key. 
     
     
         6 . An apparatus for encrypting data, the apparatus comprising:
 a memory configured to store data to be encrypted; and   a processor configured to
 first encode the data in accordance with a first keyed transformation comprising a table lookup using an index value, wherein no entry in the table is equal to its corresponding index; and 
 second encode the first encoded data. 
   
     
     
         7 . The apparatus of  claim 1 , wherein the keyed transformation is a non-linear transformation. 
     
     
         8 . The apparatus of  claim 1 , wherein the processor performs the second encoding in accordance with a second keyed transformation comprising selecting an entry from a second table in accordance with a second index and wherein the second table has no entry equal to its corresponding index. 
     
     
         9 . The apparatus of  claim 8 , wherein the processor is further configured to perform four additional encodings. 
     
     
         10 . The apparatus of  claim 1 , wherein at least one of the first and second indexes is a portion of a key. 
     
     
         11 . A computer-program product for wireless communications, comprising:
 a computer-readable medium comprising code for:
 first encoding data in accordance with a keyed transformation; and 
 second encoding the first encoded data; 
 wherein the first keyed transformation comprising selecting an entry from a first table in accordance with a first index and wherein the first table has no entry equal to its corresponding index. 
   
     
     
         12 . The apparatus of  claim 1 , wherein the keyed transformation is a non-linear transformation. 
     
     
         13 . The apparatus of  claim 1 , wherein the processor performs the second encoding in accordance with a second keyed transformation comprising selecting an entry from a second table in accordance with a second index and wherein the second table has no entry equal to its corresponding index. 
     
     
         14 . The apparatus of  claim 1 , wherein at least one of the first and second indexes is a portion of a key. 
     
     
         15 . An apparatus for encrypting data, the apparatus comprising:
 means for storing data to be encrypted; and   means for first encoding the stored data in accordance with a first keyed transformation comprising a table lookup using an index value, wherein no entry in the table is equal to its corresponding index; and   means for second encoding the first encoded data.