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Dark Skippy: A New Attack on Bitcoin Hardware Wallets? With Nick, Lloyd and Robin SLP597

Dark Skippy: A New Attack on Bitcoin Hardware Wallets? With Nick, Lloyd and Robin SLP597

Stephan Livera Podcast vor 2 Jahren

0:00

1:06:04

Dark Skippy is a new attack that in theory, makes it much easier
for a malicious person to steal your coins. Listen in to learn
about some of the ins and outs here, as well as mitigation and
the path forward for the industry from @utxoclub , @LLFOURN &
@robin_linus .

Why air gapping is not the be all end all

Dark Skippy in context with other attacks

Security while signing transactions, and security while
generating keys

RFC6979 Deterministic nonce generation

Updating PSBT to help mitigate this attack

Summary

The conversation discusses the ‘Dark Skippy’ attack, a new method
for leaking secret keys from a malicious signing device. The
attack takes advantage of the nonces used in the Schnorr and
ECDSA signature schemes. The new attack vector can potentially
extract private keys and seed words from hardware wallets. The
attack targets the nonce generation process during key generation
and signing. The previous versions of this attack were
inefficient, but Dark Skippy improves upon them. The contributors
explain how the attack came about and its implications for
hardware wallet security. They also discuss the RFC6979
deterministic nonce generation and the concept of anti-klepto
signing protocols as mitigations against the attack.

While Dark Skippy is a sophisticated attack, it requires a high
level of expertise and is not currently seen in the wild. The
discussion highlights the importance of secure boot, upgrading
the Partially Signed Bitcoin Transaction (PSBT) process, and
improving the randomness of upfront key generation as potential
mitigations.

However, it is emphasized that current reputable hardware wallets
still provide a high level of security, and there is no immediate
action required for users.

Takeaways

Dark Skippy is a new attack that leaks secret keys from a
malicious signing device.

The attack exploits the nonces used in the Schnorr and ECDSA
signature schemes.

Previous versions of this attack were inefficient, but Dark
Skippy improves upon them.

Mitigations against the attack include the RFC6979
deterministic nonce generation and anti-klepto signing
protocols. Dark Skippy is a sophisticated attack that targets
the nonce generation process during key generation and
signing.

Mitigations for Dark Skippy include implementing secure boot,
upgrading the PSBT process, and improving the randomness of
upfront key generation.

Reputable hardware wallets currently provide a high level of
security, and there is no immediate action required for
users.

The discussion highlights the importance of ongoing research
and development to enhance the security of hardware wallets
and protect against potential future attacks.

Timestamps:

(00:00) - Intro

(00:45) - What is ‘Dark Skippy’?

(04:39) - Is it an old attack vector? Bitcoin’s security evolving
with time

(12:41) - Sponsor

(15:22) - What is a nonce?, RFC6979 Deterministic nonce
generation

(22:55) - Common ways of people losing their Bitcoin

(31:08) - Sponsor

(32:07) - Anti-klepto signing protocols; ways to mitigate risks
of losing coins

(39:51) - Updating PSBT to help mitigate this attack

(43:26) - The role of Multisig in preventing the attack

(49:57) - Other attack vectors in malicious actor’s toolkit

(56:49) - Summarizing the steps to improve the ecosystem security

(1:00:18) - Closing thoughts

Links:

https://darkskippy.com/

https://frostsnap.com/

https://x.com/LLFOURN

https://x.com/robin_linus

https://x.com/utxoclub

https://x.com/utxoclub/status/1820520960476561825

Sponsors:

CoinKite.com (code LIVERA)

mempool.space/accelerator

Stephan Livera links:

Follow me on X: @stephanlivera

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