Device for the conversion of a digital block and use of same

• US 5,214,703 A
• Filed: 01/07/1992
• Issued: 05/25/1993
• Est. Priority Date: 05/18/1990
• Status: Expired due to Term

• Current Assignee: Nagravision SA (Kudelski SA)
• Original Assignee: Ascom Tech AG
• Inventors: Massey, James L., Lai, Xuejia
• Primary Examiner(s): Swann, Tod R.
• Application Number:
  US07/781,235
• Time in Patent Office: 504 Days
• Field of Search: 380/36, 380/37, 380/42, 380/43, 380/45, 380/49, 380/50, 380/28, 380/29
• US Class Current: 380/37
• CPC Class Codes: H04L 2209/125 Parallelization or pipelining, e.g. for accelerating processing of cryptographic operations
• CPC Class Codes: H04L 2209/24 Key scheduling, i.e. generating round keys or sub-keys for block encryption
• CPC Class Codes: H04L 9/0625 with splitting of the data block into left and right halves, e.g. Feistel based algorithms, DES, FEAL, IDEA or KASUMI
• CPC Class Codes: Y04S 40/20 Information technology specific aspects, e.g. CAD, simulation, modelling, system security

Abstract

The device (12) comprises nine encryption stages (61.1, 61.2, 69), the first eight of which are constructed identically. It further comprises a key subblock generation unit (63), an input unit (21), and an output unit (79). It serves for the block-by-block encryption of a plaintext (X) proceeding from a message source (11) into a ciphertext (Y) to be delivered on a transmission line (13), wherein a secret key block (Z) is inputted beforehand via a secure channel 17. The encryption is effected in a step-by-step and parallel manner for four subblocks (X₁ -X₄ ; W₁₁ -W₁₄ ; W₂₁ -W₂₄ ; W₈₁ -W₈₄ ; Y₁ -Y₄). Every encryption stage (61.1, 61.2, 69) comprises four first inputs (25-28; 35-38), six and four second inputs (29, 30, 32, 33, 49, 52; 129, 130, 132, 133), respectively, and four outputs (75-78). A total of fifty-two key subblocks (Z₁ -Z₅₂) which are formed from the key block (Z) are connected to the second inputs. The device (12) can also serve, without being altered, for the decryption of an incoming ciphertext (Y). Different key subblocks need only be connected to the second inputs for this purpose.

Claims

1. A device for converting an initial digital block into an assigned final digital block using at least one freely selectable control block, the initial and final digital blocks each having a first number of digits (N), the device comprising:

first input means for receiving at least two initial subblocks, wherein the initial digital block is subdivided to form the initial subblocks, the initial subblocks each having a second number of digits (m);

second input means for receiving at least two control blocks, each control block having the second number of digits (m);

logic means for performing serial operations of at least two different types upon the initial subblocks and the control blocks, the logic means comprising;

at least four operation units, each having first and second inputs for receiving blocks to be operated upon and an output for sending an output block resulting from the logical operation performed, the blocks operated upon and the output block each having the second number of digits (m);

wherein the blocks operated upon by the operation units include the initial subblocks, the control blocks, and the output blocks;

wherein the majority of the operation units are arranged so that the operation unit which operates upon the output block of a previous operation unit performs an operation different from the previous operation unit; and

wherein the operation units perform the operations selected from and and ; and

,

output means for transmitting at least two final subblocks, the final subblocks forming the assigned final digital block, wherein the final subblocks are converted blocks which correspond to the initial subblocks.

2. The device of claim 1, wherein:

the first input means receives first and second initial subblocks,

the second input means receives first and second control blocks,

the output means provides for the output of first and second final subblocks, and

the logic means performs primary encryption logic, the logic means comprising first, second, third, and fourth operation units which perform operation selected from and , and wherein;

the first operation unit performs the operation on the first initial subblock and the first control block to form a first output block;

the second operation unit performs the operation on the second initial subblock and the first output block to form a second output block;

the third operation unit performs the operation on the second output block and the second control block to form the second final subblock; and

,

the fourth operation performs the operation on the first output block and the second final subblock to form the first final subblock.

3. The device of claim 1, wherein:

the first input means receives first, second, third and fourth initial subblocks;

the second input means receives first and second control blocks, and;

the logic means performs extended primary encryption logic, wherein the logic means comprises;

a first operation unit for performing the operation on the first and third initial subblocks to form a first output block;

a second operation unit for performing the operation on the second and fourth initial subblocks to form a second output block;

central logic means for operating on the first and second output blocks and the first and second control blocks to form third and fourth output blocks;

a third operation unit for performing the operation on the third output block and the first initial subblock to form a first final subblock;

a fourth operation unit for performing the operation on the third output block and the third initial subblock to form a third final subblock;

a fifth operation unit for performing the operation on the fourth output block and the second initial subblock to form a second final subblock; and

,

a sixth operation unit for performing the operation on the fourth output block and the fourth initial subblock to form a fourth final subblock.

4. The device of claim 1, wherein:

the first input means receives first, second, third and fourth initial subblocks;

the second input means receives first, second, third, fourth, fifth, and sixth control blocks;

the output means provides for first, second, third and fourth final subblocks, and

the logic means performs encryption logic having a first and second stage, wherein the first stage comprises;

a first operation unit performing the operation on the first initial subblock and the first control block to form a first output block;

a second operation performing the operation on the second initial subblock and the second control block to form a second output block;

a second operation performing the operation on the second plaintext subblock and the second control block to form a second output block;

a third operation unit performing the operation on the third plaintext subblock and the third control block to form a third output block;

a fourth operation unit performing the operation on the fourth plaintext subblock and the fourth control block to form a fourth output block; and

the second stage of the encryption logic performs extended primary encryption logic, the second stage comprising;

a fifth operation unit for performing the operation on the first and third output blocks to form a fifth output block;

a sixth operation unit for performing the operation on the second and fourth output blocks to form a sixth output block;

central logic means for operating on the fifth and sixth output blocks and the fifth and sixth control blocks to form seventh and eighth output blocks;

a seventh operation unit for performing the operation on the seventh output block and the first output block to form the third cyphertext subblock;

an eighth operation unit for performing the operation on the seventh output block and the third output block to form the first cyphertext subblock;

a third operation unit performing the operation on the third initial subblock and the third control block to form a third output block;

a fourth operation unit performing the operation on the fourth initial subblock and the fourth control block to form a fourth output block; and

the second stage of the encryption logic performs extended primary encryption logic, the second stage comprising;

a fifth operation unit for performing the operation on the first and third output blocks to form a fifth output block;

a sixth operation unit for performing the operation on the second and fourth output blocks to form a sixth output block;

central logic means for operating on the fifth and sixth output blocks and the fifth and sixth control blocks to form seventh and eighth output blocks;

a seventh operation unit for performing the operation on the seventh output block and the first output block to form the third final subblock;

an eighth operation unit for performing the operation on the seventh output block and the third output block to form the first final subblock;

a ninth operation unit for performing the operation on the eighth output block and the second output block to form the fourth final subblock; and

,

a tenth operation unit for performing the operation on the eighth output block and the fourth output block to form the second final subblock.

5. The device of claim 4, wherein the central logic means performs primary encryption logic, the central logic means comprising eleventh, twelfth, thirteenth, and fourteenth operation units which perform operations selected from and , and wherein:

the eleventh operation unit performs the operation on the fifth output block and the fifth control block to form an eleventh output block;

the twelfth operation unit performs the operation on the sixth output block and the eleventh output block to form a twelfth output block;

the thirteenth operation unit performs the operation on the twelfth output block and the sixth control block to form the eighth output block; and

,

the fourteenth operation unit performs the operation on the eleventh output block and the eighth output block to form the seventh output block.

6. The device of claim 1, wherein:

the first input means receives first, second, third and fourth initial subblocks;

the second input means receives first, second, third, fourth, fifth, and sixth control blocks;

the output means provides for first, second, third and fourth final subblocks, and

the logic means performs encryption logic in first and second stages, wherein the first stage comprises;

a first operation unit for performing the operation on the first initial subblock and the first control block to form a first output block;

a second operation unit for performing the operation on the second initial subblock and the second control block to form a second output block;

a third operation unit for performing the operation on the third initial subblock and the third control block to form a third output block;

a fourth operation unit for performing the operation on the fourth initial subblock and the fourth control block to form a fourth output block; and

the second stage of the encryption logic performs extended primary encryption logic, the second stage comprising;

a fifth operation unit for performing the operation on the first and third output blocks to form a fifth output block;

a sixth operation unit for performing the operation on the second and fourth output blocks to form a sixth output block;

central logic means for operating on the fifth and sixth output blocks and the fifth and sixth control blocks to form seventh and eighth output blocks;

a seventh operation unit for performing the operation on the seventh output block and the first output block to form the first final subblock;

an eighth operation unit for performing the operation on the seventh output block and the third output block to form the second final subblock;

a ninth operation unit for performing the operation on the eighth output block and the second output block to form the third final subblock; and

,

a tenth operation unit for performing the operation on the eighth output block and the fourth output block to form the fourth final subblock.

7. The device of claim 6, wherein the central logic means performs primary encryption logic, the central logic means comprising eleventh, twelfth, thirteenth, and fourteenth operation units which perform operations selected from and , and wherein:

the eleventh operation unit performs the operation on the fifth output block and the fifth control block to form an eleventh output block;

the twelfth operation unit performs the operation on the sixth output block and the eleventh output block to form a twelfth output block;

the thirteenth operation unit performs the operation on the twelfth output block and the sixth control block to form the eighth output block; and

,

the fourteenth operation unit performs the operation on the eleventh output block and the eighth output block to form the seventh output block.

8. The device of claim 1, wherein:

the first input means receives first, second, third and fourth initial subblocks;

the second input means receives a third number of control blocks (X); and

the logic means comprises;

a fourth number of identical stages (Y), each of the stages having four inputs and four outputs and performing identical operations, the four outputs of one stage being connected to the four inputs of the next stage; and

,

a final stage having four operation units selected from and , for performing four logical operations in a parallel manner to create first, second, third and fourth final subblocks; and

the output means transmits the first, second, third and fourth final subblocks, wherein;

the number of control blocks received by the second input is governed by the equation;

space="preserve" listing-type="equation">X=Y+4; and

wherein, the first operation unit of the final stage performs the operation on the first output block of the Yth stage and the X-3th control block to form the first final subblock,

the second operation unit of the final stage performs the operation on the second output block of the Yth stage and the X-2th control block to form the second final subblock,

the third operation unit of the final stage performs the operation on the third output block of the Yth stage and the X-1th control block to form the third final subblock, and

the fourth operation unit of the final stage performs the operation on the fourth output block of the Yth stage and the Xth control block to form the fourth final subblock.

9. The device of claim 1, wherein the initial digital block is a readable block and the final digital block is an encoded block.

10. The device of claim 1, wherein the initial digital block is an encoded block and the final digital block is a readable block.