Authenticated QKD protocol using onetime ID

1
Authenticated QKD protocol using one-time ID

• GSIS / CIST
• Hwa Yean Lee
• 2005. 2. 21

2
Contents

• Introduction
• Authentication with one-time ID
• Quantum Key distribution
• Security proof
• Conclusion

3
1. Introduction

• QKD (Quantum Key Distribution) protocols
• Advantage
• Unconditional security
• Disadvantage
• Vulnerability to the Man-in-the middle
  attack

4
1. Introduction(2)

• Miloslav Dusek, Ondrej Haderka, Martin Hendrych,
  and Robert Myska, PRA, 60, 149-156 (1999)
• Bao-Sen Shi, Jian Li, Jin-Ming Liu, Xiao-Feng
  Fan, Guang-Can Guo, Physics Letters A 281  83-87
  (2001)
• Guihua Zeng and Weiping Zhan, PRA, 61, 022303
  (2000)
• Daniel Ljunggren, Mohamed Bourennane, and Anders
  Karlsson, PRA, 62, 022305 (2000)
• Takashi Mihara, PRA, 65, 052326 (2002)

5
2. Authentication with one-time ID

• Preparation
• Each user register him to the arbitrator
• secret user and one-way function
• One-way authentication key of a user, Alice is
• where is a count.
• If is 1, then the Hadamard operator
  is applied, else the identity operator is
  applied to the ith qubit.
• If does not have enough length to
  encode the qubits, then can be
  used, where .

6
2. Authentication with one-time ID (2)

• Procedure of the authentication
• Alice request a secure communication with Bob to
  the arbitrator.
• The arbitrator prepares GHZ tripartite
  states.
• He encodes Alices and Bobs particles of GHZ
  states with and ,
  respectively.
• where is Alices authentication
  key
• and is Bobs.

7
2. Authentication with one-time ID (3)

• Procedure of the authentication(2)
• The arbitrator sends the encoded qubits to Alice
  and Bob respectively.
• Alice and Bob decode their qubits with their
  authentication key and selects some bits.
• Alice and Bob measure the bits and compare the
  results.
• If the results are same, they can authenticate
  each other and do the following key distribution
  procedure. Otherwise they abort the protocol.

8
2. Authentication with one-time ID (4)

• Transformation of the GHZ states

9
3. Quantum Key distribution

• Procedure of the key distribution
• Using the remaining particles after
  authentication, Alice and Bob randomly make an
  operation either or on each particles,
  respectively.
• Alice sends her particles to the arbitrator and
  Bob sends his to Alice.
• The arbitrator perform C-NOT operation, where the
  control qubit is his and the target qubits is
  from Alice.
• The arbitrator measures each qubits(Alices and
  his) and announces the measurement outcomes are
  same(O) or not(X).

10
3. Quantum Key distribution (2)

• Procedure of the key distribution (2)
• Alice measures the GHZ particles received from
  Bob.
• Using the information published by the
  arbitrator, Alice can find Bobs sequence of the
  operations.
• The Bobs sequence of the operations can be used
  as a raw secret key.

11
3. Quantum Key distribution (3)
12
4. Security proof

• Man-in-the middle attack
• In the authentication process
• Eve introduces errors
• with probability ¼
• for each check bit
• in the authentication
• procedure.
• On knowing
• the hash function,
• Eve can estimate only
• some bits of hashed value.

13
4. Security proof (2)

• Intercept-resend attack
• Intercepts both the qubits heading to Alice or
  Bob in the authentication and the qubits heading
  to Alice or the authentication in the key
  distribution.
• When Eve intercepts one-side in the key
  distribution,
• the probability of detection is 3/8.
• When Eve intercepts both-side in the key
  distribution,
• the probability of detection is 7/16.
• But she cannot be aware of the exact key since
  Alice and Bobs information of operations are not
  exposed to Eve.

14
4. Security proof (3)

• Intercept-resend attack (2)
• Intercept only the qubits transmitted in the key
  distribution
• Eve only can know Alice and Bob use same
  operation or not.
• The probability of inferring correct key is
  .

15
4. Security proof (4)

• Eve Eavesdrops Alices (Bobs) qubits
  transmitted to the arbitrator (Alice) after Alice
  and Bob make operations on decoded GHZ states

16
5. Conclusion

• QKD with authentication using one-time ID is
  proposed.
• Authentication with one-time ID can be used on
  the various fields of quantum cryptography.
• The neutrality of the arbitrator is important
  for the security of the proposed scheme.
• ? More research on this problem are needed.