Variant key matrix cipher system

• US RE30,957 E
• Filed: 06/30/1980
• Issued: 06/01/1982
• Est. Priority Date: 10/15/1973
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Feistel, Horst
• Primary Examiner(s): Birmiel, Howard A.
• Application Number:
  US06/164,402
• Time in Patent Office: 701 Days
• Field of Search: 375/2, 178/22.17, 178/22.19, 364/717
• US Class Current: 380/262
• CPC Class Codes: H04L 2209/08 Randomization, e.g. dummy operations or using noise
• CPC Class Codes: H04L 9/065 Encryption by serially and continuously modifying data stream elements, e.g. stream cipher systems, RC4, SEAL or A5/3

Abstract

This is a cipher system for enciphering a stream of binary data by means of a product cipher. A clear message represented in a binary data format is transformed into a cipher message by operating on each bit of clear information with a complex modulo-two addition function. This function is dependent on previous internal cipher digits transmitted and varies for each message bit processed. The function is developed by continually shifting a key matrix under the control of a varying control matrix. The control matrix is formed from the sub-product of the complex function developed in generating each cipher bit.

Claims

1. A variant key cryptographic system comprising:

input means for introducing a plurality of electrical signals in binary form as message information to be enciphered or deciphered;

priming means for presenting a plurality of random binary signals to said input means to initialize the system prior to introducing message information thereto,

matrix storage means for arranging a cipher key in an n×

m matrix array, wherein m and n are greater than 1;

a plurality of modulo-two adders interconnected with each other for adding selected elements from said matrix with binary signals obtained from said input means;

feedback means connected to said plurality of modulo-two adders;

non-affine transformation means connected to said feedback means for transforming the feedback signals present on the lines contained in said feedback means;

shift control means connected to said non-affine transformation means for rearranging selected matrix elements within said n×

m matrix array.

2. The system as defined in claim 1 wherein said plurality of modulo-two adders are arranged in a cascaded fashion.

3. The system as defined in claim 2 wherein said priming means is an external source of random binary signals.

4. The system as defined in claim 2 wherein said feedback means further comprises a plurality of lines connected to intermediate stages of said modulo-two adders and at least one line connected to an element within said matrix which element is also connected to one of said plurality of modulo-two adders.

5. The system as defined in claim 4 wherein said non-affine tranformation means is a substitution device.

6. The system as defined in claim 5 wherein said substitution device comprises coding-decoding means for converting from one base number to another base number.

7. The system as defined in claim 6 wherein said matrix consists of a plurality of shift registers each capable of shifting information within the register for rearranging a column or row of the matrix;

shift control output means for specifying the number of shifts that are to be executed by each of said plurality of shift registers.

8. A variant key cryptographic system comprising:

input means for introducing a plurality of electrical signals in binary form as message information to be enciphered or deciphered;

priming means for presenting a plurality of pseudo-random binary signals to the input means to initialize the system prior to introducing message information thereto,

matrix storage means for arranging a cipher key in an n×

m matrix array wherein m and n are greater than 1;

a plurality of modulo-two adders interconnected with each other for adding selected elements from said matrix with binary signals obtained from said input means;

feedback means connected to said plurality of modulo-two adders;

first non-affine transformation means connected to said feedback means for transforming the feedback signals present on the lines contained in said feedback means;

shift control means connected to said first non-affine transformation means for rearranging selected matrix elements within said n×

m matrix array;

second feedback means connected to selected elements of said matrix for providing a binary word to a second non-affine transformation means;

said second non-affine transformation means generating a variant binary vector that is stored in selected elements within the key matrix.

9. The system as defined in claim 8 wherein said second non-affine transformation means is a substitution device. .Iadd.

10. A variant key cryptographic system comprising:

means for introducing a plurality of electrical signals in binary form as message information to be enciphered or deciphered;

priming means for presenting a plurality of random binary signals to said input means to initialize the system prior to introducing message information thereto,

means for storing and rearranging a cipher key,

a plurality of modulo-two adders interconnected with each other for adding selected elements from said storage means with binary signals obtained from said input means;

feedback means connected to said plurality of modulo-two adders;

non-affine transformation means connected to said feedback means for transforming the feedback signals present on the lines contained in said feedback means;

control means connected to said non-affine transformation means for rearranging selected elements within said storage means. .Iaddend. .Iadd.

11. A variant key cryptographic system comprising;

input means for introducing a plurality of electrical signals in binary form as message information to be enciphered or deciphered;

priming means for presenting a plurality of pseudo-random binary signals to the input means to initialize the system prior to introducing message information thereto,

storage means for storing and rearranging a cipher key;

a plurality of modulo-two adders interconnected with each other for adding selected elements from said storage means with binary signals obtained from said input means;

feedback means connected to said plurality of modulo-two adders;

first non-affine transformation means connected to said feedback means for transforming the feedback signals present on the lines contained in said feedback means;

control means connected to said first non-affine transformation means for rearranging selected elements within said key storage means;

second feedback means connected to selected elements of said storage means for providing a binary word to a second non-affine transformation means;

said second non-affine transformation means generating a variant binary vector that is stored in selected elements within the key storage means. .Iaddend.