This Week in Custody is a newsletter covering technical and narrative developments in digital asset custody written for wallet engineers, digital asset operators, and security engineers.
Bitcoin
Taproot is now active on mainnet which means you can safely spend P2TR outputs. To get a gist of benefits that Taproot brings outside of application development see Lightning in a Taproot World, scriptless scripts, Discreet Log Contracts, SIGHASH_ANYPREVOUT, and ring signatures over taproot scripts.
Ledger is planning to support PSBTs and output descriptors in their Bitcoin firmware. See their repo for more details.
New full Bitcoin implementation written in C.
There is speculation that some mining pools are not enforcing the new Taproot rules. Several pools have flagged support for the soft-fork but have failed to include a P2TR transaction in their blocks.
Several wallet providers have begun exposing Taproot features to their users. Muun Wallet implements MuSig2. Blockstream’s Green adds support for Bech32m and sending to P2TR scripts. Bitgo has full support for sending and receiving P2TR.
Muun Wallet adds output script descriptors to improve wallet recovery. Nice!
Ethereum
Paradigm creates an interesting CTF on rinkeby. A solution can be found here.
Video tutorial to dapptools. Written guide to testing with dapptools.
Overview of new features in WalletConnect v2.
Optimism successfully launched their latest upgrade allowing for EVM equivalence.
Other Chains
Report from Polkadot on utility token design.
Technical overview of transaction fee calculation in Solana.
Figment shares a tutorial on building a Solana wallet.
OFAC adds Monero “addresses” for the first time.
Security
A new approach to /dev/random.
Signing arbitrary data with SSH keys.
SeedSigner shares insights into building a wallet.
Disclosure of a ransomware attack on Trezor and Keepkey wallets.
MacOS 0-days are used against Hong Kong activists.
Paper on async MPC.
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