Kleptography

Source: Wikipedia, the free encyclopedia.

Kleptography is the study of stealing information securely and subliminally. The term was introduced by Adam Young and Moti Yung in the Proceedings of Advances in Cryptology – Crypto '96.[1] Kleptography is a subfield of

Sandia National Laboratory.[2][3][4] A kleptographic backdoor is synonymously referred to as an asymmetric backdoor. Kleptography encompasses secure and covert communications through cryptosystems and cryptographic protocols. This is reminiscent of, but not the same as steganography
that studies covert communications through graphics, video, digital audio data, and so forth.

Kleptographic attack

Meaning

A kleptographic attack is an attack which uses

smartcard, or a Trusted Platform Module
, a successful attack could go completely unnoticed.

A reverse engineer might be able to uncover a backdoor inserted by an attacker, and when it is a symmetric backdoor, even use it themself.[5] However, by definition a kleptographic backdoor is asymmetric and the reverse-engineer cannot use it. A kleptographic attack (asymmetric backdoor) requires a private key known only to the attacker in order to use the backdoor. In this case, even if the reverse engineer was well-funded and gained complete knowledge of the backdoor, it would remain useless for them to extract the plaintext without the attacker's private key.[5]

Construction

cryptotrojan that infects a cryptosystem and opens a backdoor for the attacker,[citation needed] or can be implemented by the manufacturer of a cryptosystem. The attack does not necessarily have to reveal the entirety of the cryptosystem's output; a more complicated attack technique may alternate between producing uninfected output and insecure data with the backdoor present.[8]

Design

Kleptographic attacks have been designed for

kleptographic attacks.[9]
In each case, the attacker is able to compromise the particular cryptographic algorithm or protocol by inspecting the information that the backdoor information is encoded in (e.g., the public key, the digital signature, the key exchange messages, etc.) and then exploiting the logic of the asymmetric backdoor using their secret key (usually a private key).

A. Juels and J. Guajardo[10] proposed a method (KEGVER) through which a third party can verify RSA key generation. This is devised as a form of distributed key generation in which the secret key is only known to the black box itself. This assures that the key generation process was not modified and that the private key cannot be reproduced through a kleptographic attack.[10]

Examples

Four practical examples of kleptographic attacks (including a simplified SETUP attack against RSA) can be found in JCrypTool 1.0,

kleptographic attacks
by means of the KEGVER method is also implemented in JCrypTool.

The

elliptic curve cryptography, and NSA is thought to hold a private key which, together with bias flaws in Dual_EC_DRBG, allows NSA to decrypt SSL traffic between computers using Dual_EC_DRBG for example.[13] The algebraic nature of the attack follows the structure of the repeated Dlog Kleptogram in the work of Young and Yung
.

References

  1. ISBN 978-3-540-68697-2
    .
  2. ISBN 978-1-4684-4732-3
    .
  3. ISBN 978-3-540-16076-2
    .
  4. ISBN 978-3-540-57600-6
    .
  5. ^ a b c Esslinger, Bernhard; Vacek, Patrick (20 February 2013). "The Dark Side of Cryptography: Kleptography in Black-Box Implementations". Infosecurity Magazine. Retrieved 18 March 2014.
  6. ^ Young, Adam (2006). "Cryptovirology FAQ". Cryptovirology.com. Archived from the original on 9 May 2017. Retrieved 18 March 2014.
  7. S2CID 52896242
    .
  8. ^
    ISBN 978-0-7645-6846-6
    .
  9. ^ Zagórski, Filip; Kutyłowski, Mirosław. "Bezpieczeństwo protokołów SSL/TLS i SSL w kontekście ataków kleptograficznych" [Security of SSL/TLS and SSL protocols in the context of kleptographic attacks]. kleptografia.im.pwr.wroc.pl (in Polish). Archived from the original on 2006-04-23.
  10. ^
    ISSN 0302-9743. Archived from the original
    (PDF) on 2013-05-12.
  11. ^ https://github.com/jcryptool JCrypTool project website
  12. ^ Esslinger, B. (2010). "Die dunkle Seite der Kryptografie – Kleptografie bei Black-Box-Implementierungen". <kes> (in German). No. 4. p. 6. Archived from the original on 2011-07-21.
  13. ^ Green, Matthew (September 18, 2016). "The Many Flaws of Dual_EC_DRBG". Retrieved November 19, 2016.
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