His work connects hardware self-custody, open firmware and interoperable wallet recovery. Attribution is shared: Trezor was collaborative, BIP39 has four authors and SLIP39 six; a specification is not the same as a product implementation.
Rusnák uses the name Stick. Primary records identify him as a SatoshiLabs co-founder, Trezor developer and author or co-author of public specifications; his GitHub also documents sustained open-source work. [SatoshiLabs — our story] [SatoshiLabs — presskit and current leadership] [Pavol Rusnák — personal FOSS and Bitcoin archive]
He connected with Marek “Slush” Palatinus at Prague hackerspace brmlab. They explored a device that signed transactions away from a general computer and, with Alena Vránová, built SatoshiLabs. [SatoshiLabs — our story] [Trezor — a decade of the first hardware wallet] [brmlab — Prague hackerspace]
Trezor Model One keeps and uses private keys in a separate device, with transaction confirmation on its screen. A hardware wallet does not validate all Bitcoin state by itself and still depends on correct display, backup and user procedure. [Trezor — a decade of the first hardware wallet] [Trezor firmware — source repository] [Trezor hardware — source repository]
Trezor publishes firmware source and hardware designs for outside review, building and attack. Openness does not guarantee flawless hardware or an untampered unit, but materially expands independent verification. [Trezor firmware — source repository] [Trezor hardware — source repository]
BIP39, assigned on 10 September 2013, names Marek Palatinus, Pavol Rusnák, Aaron Voisine and Sean Bowe. It maps computer entropy plus checksum to 12–24 words and then a seed; the words back up a secret, not coins stored inside a device. [BIP39 — mnemonic code specification]
BIP43 and BIP44 name Palatinus and Rusnák. BIP43 introduced a purpose branch; BIP44 defines m / 44' / coin_type' / account' / change / address_index. A standard path aids interoperability but cannot recover a missing seed or passphrase. [BIP43 — purpose field specification] [BIP44 — multi-account hierarchy]
SLIP39, created in 2017 by six named authors, standardizes Shamir Secret Sharing as mnemonic shares with threshold recovery. It is not a compatible spare BIP39 copy: migration requires understanding groups, thresholds, passphrase and a recovery test. [SLIP39 — Shamir mnemonic shares]
Rusnák also co-authored SLIP10 for derivation across multiple curves and SLIP21 for symmetric-key trees; SLIP44 with Palatinus registers BIP44 coin types. These are interoperability specifications, not proof that every implementation is secure. [SLIP10 — universal private-key derivation] [SLIP21 — symmetric-key hierarchy] [SLIP44 — registered coin types]
In 2021 SatoshiLabs announced that Trezor’s CTO role passed to Tomáš Sušánka while Rusnák continued in group management. The current presskit calls him SatoshiLabs co-founder and CTO, so the two corporate roles must not be conflated. [SatoshiLabs — presskit and current leadership] [SatoshiLabs — Trezor CTO transition]
Rusnák’s precise legacy is not one solitary invention: it links Trezor, open development and portable recovery standards. Credit must retain collaborators, the specification/product boundary and the user responsibility created by self-custody. [SatoshiLabs — our story] [Trezor firmware — source repository] [BIP39 — mnemonic code specification] [SLIP39 — Shamir mnemonic shares]
For the clearest picture, read this entry together with Bitcoin, Trezor, Hardware Wallet, Self-custody, SatoshiLabs, Marek “Slush” Palatinus. The reverse links also lead from SatoshiLabs, brmlab.