KT ColdSigner

Offline QR transaction signing

Only for iPhone

Free · Designed for iPhone. Not verified for macOS.

iPhone

Keep signing on a dedicated offline device. Pair with KT Wallet through QR codes, review transaction details and approve locally. Open source, built for self-custody. KT ColdSigner is the dedicated offline signing companion to KT Wallet. Keep recovery phrases and signing keys on an offline device while using a separate connected device to prepare and broadcast transactions. A SEPARATE OFFLINE WALLET Create or import wallets and protect local access with device authentication. KT ColdSigner does not fetch balances, prices or transaction history, and does not broadcast transactions. QR-BASED SIGNING Export a public-address QR for the connected KT Wallet app. Scan a pending transaction request, inspect its network, recipient, amount and available transaction details, then authenticate to sign. Show the signed-result QR to KT Wallet to broadcast from the online device. REVIEW BEFORE YOU SIGN Built-in safety checks reject unsupported or inconsistent requests. Keep the signing device offline; signing is blocked when a network connection is detected. Only approve transactions whose contents you understand. ENCRYPTED QR BACKUP Protect an exported recovery-phrase backup with a strong password and save it locally as a QR image. Import the encrypted backup with its password. Store backups and passwords carefully and verify recovery before relying on them. OPEN SOURCE KT ColdSigner, KT Wallet and the backend source code are publicly available at https://github.com/siliconnexus-jp/KT-Wallet under MPL-2.0. The frontend and backend are 100% open source. Available in English, Simplified Chinese and Japanese. No server account is required. IMPORTANT A dedicated offline phone is not a guarantee against every security risk. Device integrity, backup handling and careful transaction review remain essential. Never share recovery phrases or private keys. Losing your recovery material may result in permanent loss of access to your assets. Blockchain transactions can be irreversible. Powered by Silicon Nexus LLC

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    Information

    Seller
    Silicon Nexus LLC
    Size
    67 MB
    Category
    Finance
    Compatibility
    Requires iOS 15.0 or later.
    • iPhone
      Requires iOS 15.0 or later.
    • iPod touch
      Requires iOS 15.0 or later.
    • Mac
      Requires macOS 12.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 1.0 or later.
    Languages
    English and 2 more
    • English, Japanese, Simplified Chinese
    Age Rating
    18+
    Copyright
    © 2026 Silicon Nexus LLC
  • Developer Website
  • Privacy Policy

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