Cypherock
  • Introduction
  • Design Decisions
    • The balance between security and convenience
    • Cypherock X1 Hardware architecture
      • Using ultrasonic welding for the X1 Vault enclosure
      • Encrypted NFC communication for X1 cards
      • Using Javacards instead of MicroSD
      • Choosing USB vs QR Code
      • Why the X1 cards are not upgradeable
    • Cypherock is BIP39 compliant
    • Private keys should be near to impossible to extract
    • Conflict between trusted parties should not result in unauthorized access
    • Using Shamir Secret Sharing vs. Multi-sig
      • How is Shamir Secret Sharing implemented within Cypherock X1
      • Why Cypherock has a default 2/5 threshold scheme
      • Rejected Key Schemes
    • PIN Protection on Cypherock X1
      • Difference between backing up your PIN vs. Seed Phrase
  • Security Overview
    • Introduction
    • Keylabs - Third Party Security Audit
    • Remote Attacks
    • Physical Attacks
      • $5 Wrench Attack
      • PIN Brute Force Attack
      • Evil Maid Attack
      • Flashing Malicious Firmware
      • Side Channel Attack
      • Supply Chain Attack
  • Cypherock X1 Features
    • Eliminate messy paper backups
    • Open source with secure elements
    • Use Cypherock as a seed phrase vault
    • All-in-one Portfolio Manager
  • Getting Started
    • Download cySync
    • Import Seed Phrase from existing BIP39 compatible wallet
    • Generate a new wallet with Cypherock X1
    • How Cypherock generates your 24-word seed phrase
    • Best practices in keeping your X1 cards secure
      • Use the protective card sleeves
      • Geographical Seperation
      • Choosing your guardians
    • How do I know I am not locked-in to using only Cypherock X1
    • How do I know my Cypherock X1 is genuine?
      • Email 2FA for Product Authentication
    • How to recover your Crypto assets in the case of loss or theft
    • What happens to my Cypherock X1 if Cypherock goes out of business?
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  1. Design Decisions
  2. Cypherock X1 Hardware architecture

Using Javacards instead of MicroSD

There were a few key points that led to the usage of Javacards in comparison to SD Cards:

  1. Users cannot check the genuinity of the SD card because custom logic can not be implemented.

  2. MicroSD cards do not have flexible brute force prevention schemes.

  3. Users can not directly communicate with phones through a MicroSD card. Javacards are NFC based and hence can directly communicate.

  4. Since SD cards can not encrypt/decrypt data on its own, this inability hinders future product development and features, especially when it comes to working on crypto inheritance.

  5. Javacards are battle tested for decades in the banking industry for developing credit and debit cards whereas Micro SD cards are more generally used for larger storage of non-sensitive information.

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Last updated 2 years ago

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