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COINKITE Blog

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Stay up to date with Coinkite — COLDCARD, Opendime, Tapsigner, Blockclock. Firmware releases, security research, and Bitcoin cold storage.

Crypto / fintechSecurityEmbedded / microcontrollers

’16’17’18’19’20’21’22’23’24’25’26
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88 from 6 May 2016 to 26 Oct 2026
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monthly (23 in the last year)
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2026 23

  1. Understanding the COLDCARD Mk5 and Q Security Model
  2. COLDCARD Firmware 5.6.3 & 1.5.3Q: Codex32 and Shamir Backups
  3. Codex32 and Shamir Backups on COLDCARD
  4. Build and Run Your Own COLDCARD Firmware
  5. COLDCARD Firmware Update 5.6.2 & 1.5.2Q: Verifiable Seed Mixing; Continued Security Review; and EDGE 6.6.1X/6.6.1QX
  6. COLDCARD + Sparrow: Air-Gapped from First Address to First Signature
  7. COLDCARD Security Update: Seed Generation, Transaction Integrity, and Data Isolation
  8. Update on Customer Data Retention
  9. Adding to the Public Record on Our Ongoing Investigation
  10. Update, Sunday.
  11. Technical Deep Dive into the Entropy Issue
  12. Coldcard Security Advisory Funds from affected COLDCARD seeds are at risk if the seed lacks 50 independent, private dice rol... Jul 30, 2026
  13. One COLDCARD, Many Wallets: Better Backups with BIP-85 BIP-85 lets one COLDCARD recovery root recreate separate child seeds for compatible wallets. Here... Jul 29, 2026
  14. arca Reservations Are Open A $99 partial prepayment reserves a place in arca's limited first batch, currently targeting Janu... Jul 22, 2026
  15. Why mempool.space Matters for Bitcoin Users How the open-source mempool.space project makes Bitcoin's fee market visible, why self-hosting ma... Jul 20, 2026
  16. Offline Is Not Enough: COLDCARD vs a Disconnected Phone Why a disconnected phone or air-gapped computer cannot replace COLDCARD’s dedicated Bitcoin signi... Jul 16, 2026
  17. COLDCARD 5.5.1 and 1.4.1Q New COLDCARD Release: Versions 5.5.1 (Mk4/Mk5) and 1.4.1Q (Q) Jul 2, 2026
  18. Careers
  19. Paper spam attempts Remember letterhead? Now it’s the Newest Affinity Scam! Jun 24, 2026
  20. OPENDIME Turns 10: A Decade of Real, Physical Bitcoin Well, it finally happened. Our little USB stick that could is officially a decade old this month.... Jun 1, 2026
  21. Introducing the COLDCARD Mk5 The Mk4 is a proven workhorse. It’s secure, it’s air-gapped, and it gets the job done. But engine... Mar 10, 2026
  22. BIP-322 Support, WIF Keys, and more! New COLDCARD Feature Release: BIP-322 and WIF Support Mar 5, 2026
  23. COLDCARD Bitcoin Spending Policy Released New COLDCARD Feature Release: Spending Policies! Sep 29, 2025

2025 5

  1. Earn Sats Straight to Cold Storage with Zaprite and COLDCARD Earn Sats Straight to Cold Storage with Zaprite and COLDCARD Sep 9, 2025
  2. Coldcard Cosign and Key Teleport New COLDCARD Release: Many BIG features & Fixes! Apr 17, 2025
  3. New COLDCARD EDGE Version Released New COLDCARD EDGE Release: Versions 6.3.5X (Mk4) and 6.3.5QX (Q). Feb 19, 2025
  4. New Release: Signing and Address Display New COLDCARD Release: Versions 5.4.1 (Mk4) and 1.3.1 (Q) Feb 13, 2025
  5. New COLDCARD EDGE Version Released New COLDCARD EDGE Release: Versions 6.3.4X (Mk4) and 6.3.4QX (Q). Dec 18, 2024

2024 5

  1. Blockclock MINI/MICRO Update with BitcoinTreasuries.net New MINI and MICRO Firmware, and BitcoinTreasuries.net Dec 13, 2024
  2. Performance and Fixes New COLDCARD Release: Versions 5.4.0 (Mk4) and 1.3.0 (Q) Sep 12, 2024
  3. New COLDCARD EDGE Version Released New COLDCARD EDGE Release: Versions 5.3.3X (Mk4) and 1.2.3QX (Q) Jul 8, 2024
  4. NFC PushTx and More Updates New COLDCARD Release: Versions 5.3.2 (Mk4) and 1.2.2 (Q) Jun 26, 2024
  5. Version 5.2.1 for Mk4 Released New Mk4 Release: Version 5.2.1 (now 5.2.2) Dec 19, 2023

2023 10

  1. Corporate Adoption of TAPSIGNER for 2-Factor Authentication Corporate Adoption of TAPSIGNER for 2-Factor Authentication Oct 27, 2023
  2. Version 5.2.0 for Mk4: Seed Vault New Mk4 Release: Version 5.2.0 Oct 10, 2023
  3. Version 5.1.4 for Mk4 Released Bugfix and Enhancement Mk4 Release: Version 5.1.4 (was 5.1.3) Sep 8, 2023
  4. Donjon Faults SE2 on Mk4 Ledger’s Donjon lab has released anew presentation on Laser Fault Injection against the DS28C36B ... Sep 7, 2023
  5. Edge Firmware [developer preview] for Mk4 Announcing: Edge Firmware for Coldcard Mk4 May 12, 2023
  6. Version 5.1.2 for Mk4 Released Minor Mk4 Release: Version 5.1.2 Apr 7, 2023
  7. Version 5.1.0 for Mk4 Released Huge Mk4 Release! Version 5.1.1 (was 5.1.0) Feb 27, 2023
  8. COLDCARD Q1 Early-Bird reservation starts now. Meet the COLDCARD Q1 Feb 9, 2023
  9. Understanding The COLDCARD Mk4 Security Model and Secure Element Use Understanding The COLDCARD Mk4 Security Model and Secure Element Use Jan 10, 2023
  10. Everything You Need To Know About Passphrases A Brief on Private Keys & Wallets Nov 25, 2022

2022 5

  1. Version 5.0.6 Security Update (Virtual Disk) Version 5.0.6 Security Update for Virtual Disk Jul 29, 2022
  2. Announcing SATSCARD & TAPSIGNER Announcing SATSCARD & TAPSIGNER Jan 24, 2022
  3. Terms of Use
  4. COLDCARD Mk4 Early-Bird reservation ( $40 OFF) starts now. Excited to announce the Early Bird reservation of COLDCARD Mk4, get $40 off as many units as you’... Jan 23, 2022
  5. Version 4.1.3 Released (PSBT support in Core) Enhancements Sep 2, 2021

2021 8

  1. Version 4.1.2 Released (More QR Codes) Enhancements Jul 28, 2021
  2. Version 4.1.0 Released (Seed XOR Feature) Apr 29, 2021
  3. Version 4.0.2 Released (Countdown to Brick feature) New feature: “Countdown to Brick” Apr 7, 2021
  4. Version 4.0.0 Released (Major Internal Improvements) All New Code, Same Great Features Mar 17, 2021
  5. Version 3.2.2 Update Recommended (Multisig Security Update) Security Fix (Multisig Users) Feb 9, 2021
  6. Version 3.2.2 Released (Major Address Explorer Improvements) Major Multisig Improvements! Jan 14, 2021
  7. Version 3.2.1 Released (Major Multisig Enhancements) Major Multisig Improvements! Jan 8, 2021
  8. Testnet Considered Useful The Aledged Problem Nov 24, 2020

2020 9

  1. Version 3.1.8 Released (Lots of enhancements) Major Performance Boosts! Aug 4, 2020
  2. Version 3.1.4 Released (BIP-85 added / BIP-143 defences) Security Fix (BIP-143 replay attack) Jun 12, 2020
  3. BIP-143 Vulnerability A security researcher has reportedan attack leveraging an knownissue with how BIP-143 commits to ... Jun 3, 2020
  4. Laser Fault Injection Ledger’s Donjon lab has posted anew security report regarding the older Coldcard Mk2 .... May 18, 2020
  5. SEEDPLATE Bitcoin metal backup May 5, 2020
  6. Coldcard firmware update: 3.1.3 Apr 30, 2020
  7. COLDPOWER 9volt Battery to USB Apr 1, 2020
  8. Blockclock Firmware updated Firmware Upgrade Time! Mar 30, 2020
  9. Version 3.0.6 Released (Security Update) Security Fix (Multisig Users) Dec 19, 2019

2019 8

  1. Login Countdown and Nickname With 3.0.3 release we have two new optional features, Login Countdown and Device Nickname. Nov 6, 2019
  2. Troublesome Change Outputs Nov 1, 2019
  3. Coldcard Hardware Details Today we have posted all the information you need to be able tobuild your own Coldcard from off-t... Oct 25, 2019
  4. Coldcard Address Explorer Firmware update for powerful new feature: "The Address Explorer" Oct 8, 2019
  5. Coldcard™ Mark 3 Announcement Aug 26, 2019
  6. Possible Information Leak, Considered Unlikely Aug 7, 2019
  7. Keep Your Pins Long, and Your Peace of Mind Intact Jan 28, 2019
  8. Some Other Wallets.fail Dec 28, 2018

2018 3

  1. Coldcard Firmware 1.1.0 Nov 26, 2018
  2. Coldcard Firmware 1.0.1 Sep 5, 2018
  3. Announcing: Coldcard™ The World Needs An Open, Cheap & Ultrasecure Hardware Wallet! Pre-Order Now Dec 8, 2017

2017 4

  1. Announcing: Opendime V3 You might have noticed that the Opendime store is out-of-stock. Aug 22, 2017
  2. Opendime V2: Cyberpunk Credsticks Return The OpenDime (OpenDime.com) is one of those projects which really captures the imagination. Lik... May 20, 2017
  3. Announcing: Chrome Extension for Opendime Just as we were finalizing the firmware for V2 of Opendime(now shipping, by the way) we discovere... Mar 8, 2017
  4. Announcing: Opendime v2 – Now Genuine Verified Bitcoin Credit Stick Opendime is a small USB stick that allows you to spend Bitcoin like a dollar bill. Pass it along ... Dec 27, 2016

2016 7

  1. Real Life Cyberpunk Cred Sticks: Opendime If there’s ever any doubt that we’re currently living in a cyberpunk world, then the OpenDime (... Sep 14, 2016
  2. The Bitcoin Game Interview With Opendime Team Hello, welcome to episode 38 of The Bitcoin Game. I’m Rob Mitchell.It’s always great interviewi... Aug 21, 2016
  3. Exquisite Opendime When we first read about OpenDime, the hardware Bitcoin Wallet, we were exited by what they app... Aug 5, 2016
  4. Friends of Satoshi Opendime Video: The Zero-Trust Bitcoin Stick The 1st Bitcoin Bearer Bond or just call it a “Bitcoin Stick”. Aug 4, 2016
  5. Multiple Languages on Opendime Interface Since Opendime v1.1 multiple languages are supported right in the User Interface. 中文 🇨🇳, 日本語 🇯🇵, ... Aug 1, 2016
  6. Opendime Unboxings! Opendime is a new way to transact Bitcoin in physical form. It’s basically a bearer bond for Bitc... May 6, 2016
  7. Video: World's First Bitcoin Bearer Bond–A Bitcoin Stick! Watch a demo of the world’s first bitcoin bearer bond–a bitcoin stick! Opendime is a small USB st... Apr 27, 2016

Undated 1

  1. Responsible Disclosure