Stream cipher cryptographic system and method
AssigneeQUALCOMM Incorporated
InventorsGregory Gordon Rose, Philip Michael Hawkes
Life of this patent
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Abstract
Apparatus and method for generating a key stream is disclosed. In one embodiment, a cryptographic function is applied on input values selected from a first array of values to generate output values. Mask values are then selected from a second array of values and combined with the output values to generate a key stream block for the key stream. The first and second arrays are finite and may be implemented by a linear feedback shift register.
Claims53
A method of generating a key stream comprising:
- applying a cryptographic function on input values selected from a first array of values to generate output values;
- selecting mask values from a second array of values;
- and
- combining the output values with the mask values to generate a key stream block for the key stream;
- wherein the first and second arrays are finite.
Apparatus for generating a key stream comprising:
- means for applying a cryptographic function on input values selected from a first array of values to generate output values;
- means for selecting mask values from a second array of values;
- and
- means for combining the output values with the mask values to generate a key stream block for the key stream;
- wherein the first and second arrays are finite.
A machine readable medium used for generating a key stream comprising:
- code segment for applying a cryptographic function on input values selected from a first array of values to generate output values;
- code segment for selecting mask values from a second array of values;
- and
- code segment for combining the output values with the mask values to generate a key stream block for the key stream;
- wherein the first and second arrays are finite.
Apparatus for generating a key stream comprising:
- a linear feedback shift register (LFSR) configured to generate a first array of values, wherein the values of the first array corresponds to the values of the LFSR states;
- a nonlinear filter module configured to apply a cryptographic function on input values selected from the first array to generate output values;
- and
- a combining module configured to combine the output values with mask values selected from a second array of values to generate a key stream block for the key stream;
- wherein the first and second arrays are finite.
Dependencies are inferred from the claim text.