Method and system for data integrity protection

• US 7,298,840 B2
• Filed: 04/09/2002
• Issued: 11/20/2007
• Est. Priority Date: 05/03/2001
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Blom, Rolf, Gehrmann, Christian
• Primary Examiner(s): Barron, Jr.; Gilberto
• Assistant Examiner(s): PERUNGAVOOR, VENKATANARAY
• Application Number:
  US10/476,138
• Publication Number:
  US 20040123102A1
• Time in Patent Office: 2,051 Days
• Field of Search: 380 36- 40, 380/262
• US Class Current: 380/36
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 9/3242 involving keyed hash functions, e.g. message authentication codes [MACs], CBC-MAC or HMAC

Abstract

A method of authenticating a message (111) received via a transmission channel (108) using a Message Authentication Code (MAC). The message comprises a message body (114) and a tag (116) and the method comprises the steps of generating a second tag (115) according to a MAC function (112) on the basis of the received message body and a secret key (113), calculating a distance (117) between the received tag and generated second tag, and comparing (118) the calculated distance with a predetermined threshold value.

Claims

1. A method of authenticating data, the method comprising the steps of:

receiving a message and a corresponding first data item generated according to a first predetermined rule;

generating a second data item according to a second predetermined rule on the basis of the received message;

calculating a first distance between the received first data item and the generated second data item;

comparing the calculated first distance with a predetermined distance; and

processing the message by accepting the message if the calculated first distance is smaller than the predetermined distance value wherein the step of processing the message includes;

generating a first sequence of message sections from the message, each message section having a predetermined length;

modifying at least a first message section of the sequence of message sections;

applying at least a first permutation to at least the modified first message section of the sequence of message sections;

calculating at least one XOR sum of a result of at least the first permutation; and

calculating a hash value from the calculated at least one XOR sum.

2. A method according to claim 1, wherein the message and the first data item are received via a wireless communications channel.

3. A method according to claim 2, wherein the step of generating the second data item comprises the step of applying a predetermined permutation to a third data item derived from the message.

4. A method according to claim 3, wherein the step of generating the second data item comprises the step of combining a fourth data item derived from the message with a predetermined fifth data item.

5. A method according to claims 4, wherein the step of combining a fourth data item derived from the message with a predetermined fifth data item comprises the step of inserting predetermined binary sequences at predetermined positions of the fourth data item.

6. A method according to claim 5, wherein the step of calculating a first distance comprises the step of calculating a Hamming distance.

7. A method according to claim 1, wherein the method further comprises the step of repeating the steps of applying at least the first permutation and calculating an XOR sum a predetermined number of times.

8. A method according to claim 1, wherein the method further comprises the step of repeating the steps of processing the message using at least a second permutation.

9. A method according to claim 8, wherein the method further comprises the step of encrypting the calculated hash value.

10. A method according to claim 9, wherein the step of calculating the first distance further comprises the steps of:

dividing the first and second data items into corresponding first and second sets of data sections;

calculating a second distance between a first section of the first set of sections and a corresponding second section of the second set of sections; and

comparing the second distance with a predetermined threshold value.

11. A method according to claim 10, wherein:

the first data item is further generated on the basis of a first secret key code; and

the step of generating the second data item on the basis of the received message further comprises the step of generating the second data item on the basis of a second secret key code.

12. A method according to claim 11, wherein:

the first and second secret key codes are the same key code; and

the first and second predetermined rules are the same rule.

13. A communications system comprising:

first processing means adapted to calculate a first data item according to a first predetermined rule on the basis of a message;

a transmitter adapted to transmit the message and the generated first data item via a transmission channel;

a receiver adapted to receive the transmitted message and the transmitted first data item;

second processing means adapted to;

generate a second data item according to a second predetermined rule on the basis of the received message;

calculate a first distance between the received first data item and the generated second data item; and

compare the calculated first distance with a predetermined distance value; and

third processing means for processing the message and adapted to;

generating a first sequence of message sections from the message, each message section having a predetermined length;

modifying at least a first message section of the sequence of message sections;

applying at least a first permutation to at least the modified first message section of the sequence of message sections;

calculating at least one XOR sum of a result of at least the first permutation; and

calculating a hash value from the calculated at least one XOR sum.

14. An apparatus comprising:

a receiver adapted to receive a message and a corresponding first data item generated according to a first predetermined rule;

first processing means adapted to;

generate a second data item according to a second predetermined rule on the basis of the received message;

calculate a first distance between the received first data item and the generated second data item; and

compare the calculated first distance with a predetermined distance value; and

second processing means for processing the message and adapted to;

generating a first sequence of message sections from the message, each message section having a predetermined length;

modifying at least a first message section of the sequence of message sections;

applying at least a first permutation to at least the modified first message section of the sequence of message sections;

calculating at least one XOR sum of a result of at least the first permutation; and

calculating a hash value from the calculated at least one XOR sum.

15. An apparatus according to claim 14, wherein the apparatus is a mobile radio terminal.