Jul 1, 2022
In this episode of Bitcoin, Explained, hosts
Aaron van Wirdum and Sjors Provoost discuss reusing Bitcoin
addresses. More specifically, they explain why reusing Bitcoin
addresses is a bad idea.
Reusing Bitcoin addresses is a bad idea for roughly three reasons.
The first two of these are that it harms privacy and impedes on the
censorship resistance of Bitcoin. In the episode, Aaron and Sjors
go over a couple examples of how such a loss of privacy and
censorship resistance can negatively affect Bitcoin
users.
The third reason that reusing Bitcoin addresses is a bad idea, is
that it opens up the possibility of some niche attacks. In certain
cases, attackers could extract private keys from signatures after
coins are first spent from an address — though this does require
that a wallet implemented the signing algorithm wrongly in the
first place. There are also some scenarios where quantum computers
could in the future extract private keys from signatures if
addresses are reused.
Another type of niche attack is a timing sidechannel attack, such
as the recently disclosed Hertzbleed Attack. Sjors explains that
attackers can potentially derive a private key from a wallet by
closely monitoring how the computer that hosts the wallet behaves
when signing a transaction. This attack is more plausible if
addresses are reused.
Address reuse wiki: https://en.bitcoin.it/wiki/Address_reuse#Security
Hertzbleed attack: https://www.hertzbleed.com/