System and method for secure communication of components inside self-service automats

• US 9,331,850 B2
• Filed: 03/10/2014
• Issued: 05/03/2016
• Est. Priority Date: 12/09/2008
• Status: Active Grant

• Current Assignee: Diebold Nixdorf Systems GmbH (Diebold Nixdorf, Incorporated)
• Original Assignee: Wincor Nixdorf International GmbH (Diebold Nixdorf, Incorporated)
• Inventors: Krummel, Volker, Runowski, Matthias, Bloemer, Johannes, Nolte, Michael
• Primary Examiner(s): NGUYEN, THU HA T
• Application Number:
  US14/202,664
• Publication Number:
  US 20140192978A1
• Time in Patent Office: 785 Days
• Field of Search: 713/176, 713/184, 709/233, 380 40- 44, 235/379
• US Class Current: 1/1
• CPC Class Codes: G06F 21/606 by securing the transmission between two devices or processes
• CPC Class Codes: G06F 21/72 in cryptographic circuits
• CPC Class Codes: G06Q 20/3823 combining multiple encryption tools for a transaction
• CPC Class Codes: G06Q 20/3829 involving key management
• CPC Class Codes: G07F 19/20 Automatic teller machines [ATMs]
• CPC Class Codes: H04L 9/0861 Generation of secret information including derivation or calculation of cryptographic keys or passwords

Abstract

Method to secure the communication of components within self-service automats that are linked to each other by a bus system, having a transmitter and a receiver, characterized in that data are exchanged as tupels (C,A,R,N,Z) on the transport layer of the bus system where

• • C are the message data M encrypted with an encryption key,
  • A are the message data M authenticated with an authentication key,
  • R represents the role of a component on the bus system of active or passive participants,
  • N represents a message counter,
  • Z represents a session counter.

Claims

1. A method for securing communication of components inside a self-service automat that are connected to each other by a bus system, with a transmitter and a receiver, comprising:

encrypting data as tuples (C,A,R,N,Z, {circumflex over (N)}, {circumflex over (Z)}) by a first computing unit including memory and configured to process data;

transmitting data as tuples (C,A,R,N,Z, {circumflex over (N)}, {circumflex over (Z)}) from the transmitter to the receiver on a transport layer of the bus system;

receiving data as tuples (C,A,R,N,Z, {circumflex over (N)}, {circumflex over (Z)}) at the receiver; and

decrypting data received as tuples (C,A,R,N,Z, {circumflex over (N)}, {circumflex over (Z)}) with the first computing unit or a second computing unit including memory and configured to process data;

wherein;

C are message data M encrypted with an encryption key;

A are message data M authenticated with an authentication key;

R represents a participant role of a component on the bus system of active or passive participants;

N represents a message counter;

Z represents a session counter;

{circumflex over (N)} is a message counter for Δ

-last messages N;

{circumflex over (Z)} is a last session counter for Δ

-last messages;

the session counters Z and {circumflex over (Z)} are configured to change the encryption key for different sessions; and

for each session the session counter {circumflex over (Z)} for Δ

-last messages is transmitted and considered and the session counter Z is transmitted and not considered;

the method further comprising;

allowing Δ

-last messages to be lost during exchange of the data without informing an application layer;

transmitting from the transmitter to the receiver a pair ({circumflex over (Z)}, {circumflex over (N)}) as a current session counter; and

checking the received data for accuracy at the receiver.

2. The method of claim 1, wherein the encryption key and the authentication key are a common key K, securely filed in the components, that was generated at the time of production and assembly of the self-service automat on a basis of certificates from a public key infrastructure (PKI).

3. The method of claim 2, wherein the common key K is stored in a Trusted Platform Module (TPM).

4. The method of claim 1, wherein A:

=Auth[K_auth^R,N,M,|M|], where K^R_auth is the result of a key generation procedure using a common key K.

5. The method of claim 1, further comprising:

determining, while transmitting from the transmitter to the receiver, whether the message counter N is less than a maximum message counter N_max; and

upon the determining whether N is less than N_max, if N is less than N_max, setting N;

=N+1.

6. The method of claim 1, further comprising:

determining while transmitting from the transmitter to the receiver, whether Z is less than a maximum session number Z_max;

determining whether N is less than a maximum message number N_max;

comparing a tuple ({circumflex over (Z)},{circumflex over (N)}) to a tuple ( Z, N), wherein {circumflex over (Z)} is a session is a session number for Δ

-last messages, {circumflex over (N)} is a message number for Δ

-last messages, {circumflex over (Z)} is a last session counter, and N is a last message counter;

generating, based on the comparing, an error if more than Δ

messages have been lost;

decrypting message data, based on the comparing, if not more than Δ

messages have been lost; and

upon decrypting the message data, authenticating the message data.

7. The method of claim 6, further comprising:

decrypting the message data based on a K_dec^R and C, wherein K_dec^R is a result of a key generation procedure using a common key K;

comparing A to an authentication value A′

at the receiver, wherein A′

is determined based on K_ver^R, N, the decrypted message data, and |C|, wherein K_ver^R is a result of a key generation procedure using a common key K; and

authenticating the decrypted message data, based on the comparing of A to A′

, if A is equal to A′

.

8. The method of claim 1, wherein the self-service automat is an automated banking machine.

9. The method of claim 1, wherein C C:

=ENC[K_enc^R,Z,N,M], where K_enc^R is the result of a key generation procedure using a common key K.

10. The method of claim 1, wherein the bus system is a universal serial bus (USB).

20. The system of claim 10, wherein the bus system is a universal serial bus (USB) with wired or wireless operation.

11. A system for securing communication of components inside self-service automats comprising:

a plurality of components, inside a self-service automat, including a first component and a second component, the first component being a transmitter in communication with the second component, being a receiver, wherein the first and second components are on a bus system having a transport layer;

a plurality of configured computing units, including a first computing unit in communication with the first component and a second computing unit in communication with the second component, the first and the second computing units each including memory and configured to process data;

wherein;

the first computing unit encrypts data as tuples (C,A,R,N, {circumflex over (N)}, {circumflex over (Z)});

the transmitter transmits data as tuples (C,A,R,N, {circumflex over (N)}, {circumflex over (Z)}) to the receiver on the bus having the transport layer;

the receiver receives the data as tuples (C,A,R,N, {circumflex over (N)}, {circumflex over (Z)});

the first computing unit or the second computing unit decrypt data received as tuples (C,A,R,N, {circumflex over (N)}, {circumflex over (Z)});

{circumflex over (N)}, {circumflex over (Z)}

C are message data M encrypted with an encryption key;

A are message data M authenticated with an authentication key;

R represents a participant role of a component on the bus system, R includes active and passive;

N represents a message counter;

Z represents a session counter;

{circumflex over (N)}is a message counter for Δ

last messages N;

{circumflex over (Z)}is a last session counter for Δ

last messages;

the session counters Z and {circumflex over (Z)}are configured to change the encryption key for different sessions; and

for each session the session counter {circumflex over (Z)}for Δ

-last messages is transmitted and considered and the session counter Z is transmitted and not considered

the system further comprising a means for allowing the Δ

-last messages to be lost in a transmission, from the first component to the second component, without informing an application layer above, wherein the first component transmits a current session counter pair (N, Z) and a pair ({circumflex over (N)}, {circumflex over (Z)}) so that a check is enabled at the receiver.

12. The system of Claim 11, further comprising:

a means for generating and securely filing a common key K during the production and assembly of the self-service automat on the basis of certificates from a public key infrastructure (PKI), wherein a calculating unit uses the common key K for at least one of authentication and encryption.

13. The system of claim 12, further comprising a Trusted Platform Module (TPM) in which the common key K is filed.

14. The system of claim 12, wherein the calculating unit determines at least one of A and C;

and

wherein A;

=Auth[K_auth^R,N,M,|M|], where K_auth^R is a result of a secure authentication calculation using the common key K, and C;

=ENC[K_enc^R,Z,N,M] where K_enc^R, is a result of a secure encryption calculation using the common key K.

15. The system of claim 11, wherein the first computing unit determines whether the message counter N is less than a maximum message counter N_max, and upon determining whether N is less than N_max, the first computing unit sets N:

=N+1.

16. The system of claim 11, wherein the second computing unit:

determines whether Z is less than a maximum session counter Z_max;

determines whether N is less than a maximum message counter N_max;

compares a tuple ({circumflex over (Z)},{circumflex over (N)}) to a tuple ( Z, N), wherein {circumflex over (Z)} is the session counter for Δ

-last messages, {circumflex over (N)} is the message counter for Δ

-last messages, Z is a last session counter, and N is a last message counter;

generates, based on the comparison, an error if more than Δ

messages have been lost;

decrypts message data, based on the comparison, if not more than Δ

messages have been lost; and

upon the decryption of the message data, authenticates the decrypted message data.

17. The system of claim 16, wherein the second computing unit decrypts the message data based on K_dec^R and C, where K_dec^R is a result of a key generation procedure using a common key K.

18. The system of claim 17, wherein the second computing unit authenticates the decrypted message data, based on a comparison of A and A′

, if A is equal to A′

, wherein A′

is determined based on K_ver^R, N, the decrypted message data, and |C|, wherein K_ver^R is a result of a key generation procedure using a common key K.

19. The system of claim 11, wherein the self-service automat is an automated teller machine (ATM).

21. The system of claim 11, further comprising means for exchanging data as tuples (C,A,R,N, {circumflex over (N)}, {circumflex over (Z)}) between the first component and the second component on the transport layer of the bus system.