US 7,406,595 B1Granted

Method of packet encryption that allows for pipelining

AssigneeThe United States of America as represented by the Director, National Security Agency

InventorsVincent Michael Boyle, Jr., Christopher Mark Salter

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Abstract

A method of packet encryption and decryption that allows for pipelining. The first step is to identify the packets in a message to be encrypted. Then, a unique number is assigned to each packet. A value R is acquired. Then, a first register is initialized. An initialization vector IV is generated. Then, the first register is stepped a user-definable number of times. Then, a packet is selected. R and the unique number are combined. Then, a second register is initialized. A checksum is generated. Then, the packet is divided into blocks. A block is selected. Then, the checksum is combined with the block and designated the checksum. The block is encrypted. Then, the first and second registers are stepped. These steps are repeated for each block. Then, the checksum is encrypted. After the blocks are encrypted, the unique number, IV, the ciphertext of each block, and the encrypted checksum are transmitted. If there are any other packets to encrypt then the steps are repeated.

Claims30

Dependent claims

A method of packet encryption, comprising the steps of:

(a) identifying each packet in a message to be encrypted;
(b) assigning a unique number to each packet;
(c) acquiring a value R of width w, where w is a user-definable integer;
(d) initializing a first register of width w with R, where the first register is configured to step;
(e) generating an initialization vector IV that is a function of the contents of the first register;
(f) stepping the first register a user-definable number of times;
(g) selecting a packet that has not been processed;
(h) combining R and the unique number of the selected packet;
(i) initializing a second register of width w with the result of the last step, where the second register is configured to step;
(j) generating a checksum;
(k) dividing the selected packet into blocks of width w, padding any block to width w if necessary;
(l) selecting a block from the selected packet that has not been processed;
(m) combining the checksum with the selected block and designating the result as the checksum;
(n) encrypting the selected block as a function of the contents of the first register and the second register and designating the result as ciphertext of the selected block;
(o) stepping the first register and the second register a user-definable number of times;
(p) if a block in the selected packet has not been processed then returning to step (1), otherwise proceeding to the next step;
(q) encrypting the checksum;
(r) transmitting the unique number of the selected packet, IV, the ciphertext of each block in the selected packet, and the encrypted checksum;
and
(s) if a packet in the message has not been processed then stepping the first register a user-definable number of times and returning to step (g), otherwise stopping.

17 more elements

A method of packet decryption, comprising the steps of:

(a) receiving a transmission of an encrypted packet, where the transmission includes a unique number for the encrypted packet, an initialization vector IV, at least one ciphertext block, and an encrypted checksum;
(b) acquiring a value R of width w, where w is a user-definable integer, and where R is equal to a corresponding value used to create the received transmission;
(c) setting a second checksum equal to the unique number;
(d) decrypting IV using an inverse of a method used to form IV;
(e) initializing a first register of width w with the result of the last step, where the first register is configured to step;
(f) stepping the first register a number of times equal to a number of times used to form IV;
(g) combining R and the unique number;
(h) initializing a second register of width w with the result of the last step, where the second register is configured to step;
(i) selecting one of said at least one ciphertext blocks;
(j) combining the selected one of said at least one ciphertext block with the contents of the second register;
(k) decrypting the result of the last step using an inverse of a method used to encrypt the selected one of said at least one ciphertext block;
(l) combining the result of the last step with the contents of the first register to form a plaintext block of the selected one of said at least one ciphertext block;
(m) combining the second checksum with the result of the last step;
(n) setting the second checksum equal to the result of the last step;
(o) stepping the first register and the second register a user-definable number of times;
(p) if one of said at least one ciphertext block has not been processed then returning to step (h), otherwise proceeding to the next step;
(q) stepping the first register a user-definable number of times;
(r) combining the encrypted checksum with the result of step (f);
(s) decrypting the result of the last step using an inverse of a method used to form the encrypted checksum;
(t) combining the contents of the first register with the result of the last step;
(u) comparing the second checksum to the result of the last step;
and
(v) accepting the plaintext blocks as valid if a match is found in the last step, otherwise declaring the plaintext blocks invalid.

20 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/843,637Filed 5 May 2004
Granted: 29 Jul 2008
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

H04L 9/3236
Including means for verifying the identity or authority of a user of the system or for message authentication, e.g. authorization, entity…: using…
H04L 9/0637
Block ciphers, i.e. encrypting groups of characters of a plain text message using fixed encryption transformation: modes of operation, e.g. cipher…
H04L 2209/125
Details relating to cryptographic hardware or logic circuitry: parallelization or pipelining, e.g. for accelerating processing of cryptographic…
H04L
Digital communication