Secure communication

Patent metadata

Field	Value
Publication number	US-10009175-B2
Application number	US-201314403144-A
Country	US
Kind code	B2
Filing date	May 23, 2013
Priority date	May 23, 2012
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

A method for allowing a first party and a second party to obtain shared secret information is provided. The method comprises the steps of: obtaining, by the first party, a sequence of values A=X+N A where X is a sequence of values and N A is a random sequence associated with the first party; obtaining, by the second party, a sequence of values B=X+N B where N B is a random sequence associated with the second party; performing, by the first and second parties, a data matching procedure to identify corresponding pairs of values, a , b , in respective sequences A and B that match, wherein sequences A and B are discrete-valued sequences equal to, derived from, or derived using, sequences A and B; wherein the shared secret information is equal to, or derived from, or derived using, the matching values in sequences A and B.

First claim

The invention claimed is:

1. A method for allowing a first apparatus and a second apparatus to obtain shared secret information, the method comprising the steps of:
receiving, by the first apparatus, a first signal comprising a sequence of values X to obtain a sequence of values A=X+N A where N A is a random sequence comprising receiver noise of the first apparatus;
receiving, by the second apparatus, the first signal comprising the sequence of values X to obtain a sequence of values B=X+N B where N B is a random sequence comprising receiver noise of the second apparatus, and where N A and N B are independent of each other;
transmitting, between the first and second apparatuses, one or more second signals for performing a data matching procedure to identify corresponding pairs of matching values, a i , b i , in respective sequences A* and B*, that match, wherein the sequences A* and B* are discrete-valued sequences equal to, derived from, or derived using, the sequences A and B that comprise the receiver noise of the first and second apparatuses, respectively, such that the sequences A* and B* also comprise the receiver noise of the first and second apparatuses, respectively;
wherein the shared secret information is equal to, or derived from, or derived using, matching values in discrete-valued sequences A* and B* that comprise the receiver noise of the first and second apparatuses, respectively.

2. The method of claim 1 , wherein the data matching procedure comprises the steps of:
exchanging one or more messages between the first apparatus and the second apparatus, such that at least one of the first apparatus and the second apparatus acquires one or more acquired values, wherein at least one of the acquired values is equal to or derived from a i , and at least one of the acquired values is equal to or derived from b i ; and
performing, by at least one of the first apparatus and the second apparatus, one or more mathematical operations including a comparison operation, wherein matching of the values a i , and b i is determined from a result of the comparison operation.

3. The method of claim 1 , wherein the data matching procedure comprises performing, by an apparatus P being one of the first apparatus and the second apparatus, and an apparatus Q being other of the first apparatus and the second apparatus, the steps of:
transmitting, by apparatus P to apparatus Q, a value T 1 =ƒ 1 (p), where p is a value in the sequence, A* or B*, of apparatus P and ƒ 1 is a predetermined function;
comparing, by apparatus Q, T 1 or a value derived from T 1 with q or a value derived from q, where q is a value in the sequence, B* or A*, of apparatus Q corresponding in sequence position to p.

4. The method of claim 3 , wherein the step of comparing comprises at least one of: comparing T 1 with ƒ 1 (q); and comparing ƒ −1 1 (T 1 ) with q, where ƒ −1 1 is the inverse function of ƒ 1 .

5. The method of claim 1 , wherein the data matching procedure comprises performing, by an apparatus P being one of the first apparatus and the second apparatus, and an apparatus Q being other of the first apparatus and the second apparatus, the steps of:
transmitting, by apparatus P to apparatus Q, a value T 1 =ƒ 1 (p), where p is a value in the sequence, A* or B*, of apparatus P and ƒ 1 is a predetermined function; and
computing, by apparatus Q, a value T 2 =ƒ 2 (T 1 ,q) where ƒ 2 is a predetermined function and q is a value in the sequence, B* or A*, of apparatus Q corresponding in sequence position to p;
wherein the step of comparing comprises comparing, by at least one of the first apparatus and the second apparatus, T 2 with a predetermined value.

6. The method of claim 5 , wherein ƒ 1 (p)=p⊕r, where r is a random value and ⊕ denotes modulo-2 addition.

7. The method of claim 6 , comprising the further step of transmitting, by apparatus P to apparatus Q, a value T 3 =ƒ 3 (r), where ƒ 3 is a predetermined function;
wherein ƒ 2 (T 1 ,q)=T 1 ⊕q, and wherein the step of comparing comprises comparing, by apparatus Q, T 3 with ƒ 3 (T 2 ).

8. The method of claim 6 , comprising the further step of transmitting, by apparatus Q to apparatus P, the value T 2 , wherein ƒ 2 (T 1 ,q)=ƒ 3 (T 1 ⊕q), where ƒ 3 is a predetermined function; and
wherein the step of comparing comprises comparing, by apparatus P, ƒ 3 (r) with T 2 .

9. The method of claim 1 , wherein the data matching procedure comprises performing, by an apparatus P being one of the first apparatus and the second apparatus, and an apparatus Q being other of the first apparatus and the second apparatus, the steps of:
computing, by apparatus P, a bit value m 1 =p 1 ⊕r, where p 1 is a first bit of a value p in the sequence, A* or B*, of apparatus P, r is a random bit, and ⊕ denotes modulo-2 addition;
computing, by apparatus P, a bit value m 2 =p 2 ⊕r, where p 2 is a second bit of p;
transmitting, by apparatus P to apparatus Q, the bit values m 1 and m 2 ;
computing, by apparatus Q, a bit value m′ 1 =m 1 ⊕q 1 where q 1 is a first bit, corresponding in bit position to p 1 , of a value q in the sequence, B* or A*, of apparatus Q corresponding in sequence position to p;
computing, by apparatus Q, a bit value m′ 2 =m 2 ⊕q 2 where q 2 is a second bit of q, corresponding in bit position to p 2 ;
comparing a value m′ 1 ⊕m′ 2 with 0.

10. The method according to claim 1 , wherein the data matching procedure uses a sequence of random values r i corresponding respectively to pairs of values, a i , b i , in respective sequences A* and B*, and wherein the shared secret information is based on random values, r i , corresponding to matching values a i , b i in sequences A* and B*.

11. The method of claim 1 , comprising the further step of encoding the sequence X into the first signal and transmitting the first signal;
wherein the values of the sequence X are encoded into quantum states of the first signal; and
wherein the values of the sequence X are encoded into at least one of: an amplitude; and a phase of the first signal.

12. The method of claim 11 , wherein the first signal is encoded and transmitted by one of: the first apparatus; and an apparatus other than the first and second apparatus.

13. The method of claim 11 , wherein the step of receiving, by the second apparatus, the first signal to obtain the sequence of values B comprises detecting, by the second apparatus, the encoded values; and wherein the step of receiving, by the first apparatus, the first signal to obtain the sequence of values A comprises detecting, by the first apparatus, the encoded values.

14. The method of claim 1 , wherein the sequence X comprises at least one of: a random sequence of values; a sequence of Gaussian distributed values; and a predetermined sequence of values.

15. The method of claim 1 , comprising the further step of converting, by each of the first and second apparatus, the respective sequences A and B into corresponding discrete-valued sequences A* and B*.

16. The method of claim 15 , wherein the step of converting the sequences A and B into the corresponding discrete-valued sequences A* and B* comprises the step of:
obtaining, by each of the first and second apparatus, a respective sequence of binary values, A* and B*, corresponding respectively to A and B, by applying a predetermined discretization operation to each continuous value, a i , b i , in sequences A and B to obtain corresponding binary values in sequences A* and B*, wherein the discretization operation maps ranges of continuous values to corresponding binary values.

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Assignees

• Univ Leeds Innovations Ltd
• The Univ Of Leeds

Inventors

• Varcoe Benjamin Thomas Hornsby
• Everitt Matthew Christopher John

Classifications

• H04L9/0858

  Details about key distillation or coding, e.g. reconciliation, error correction, privacy amplification, polarisation coding or phase coding · CPC title

• H04L9/0838

  Key agreement, i.e. key establishment technique in which a shared key is derived by parties as a function of information contributed by, or associated with, each of these (network architectures or network communication protocols for key exchange in a packet data network H04L63/061) · CPC title

• H04L9/0852 Primary

  Quantum cryptography (transmission systems employing electromagnetic waves other than radio waves, e.g. light, infrared H04B10/00; wavelength-division multiplex systems H04J14/02; WDM arrangements H04J14/03) · CPC title

• H04L9/08 Primary

  Key distribution {or management, e.g. generation, sharing or updating, of cryptographic keys or passwords (network architectures or network communication protocols for supporting key management in a packet data network H04L63/06)} · CPC title

• H04L9/0816

  Key establishment, i.e. cryptographic processes or cryptographic protocols whereby a shared secret becomes available to two or more parties, for subsequent use · CPC title