The Design of the Encrypted SD Backup of ColdCard
World Crypto Network
ColdCard generates encrypted SD backups using a 12-word BIP39 passphrase (128+ bits entropy) hashed via SHA-256 to create AES-256 keys for standard 7-zip archives. Once decrypted with any 7-zip tool, the backup contains plain text private keys, extended keys, and fingerprints needed to access funds via another wallet. The design trades plausible deniability (archive filenames remain visible in the
https://relay.towardsliberty.com/cea51e0de135dade63c288938f7a99f71f5195c8c1aea700f86fe7ee3f989548.mp4
World Crypto Network
ColdCard generates encrypted SD backups using a 12-word BIP39 passphrase (128+ bits entropy) hashed via SHA-256 to create AES-256 keys for standard 7-zip archives. Once decrypted with any 7-zip tool, the backup contains plain text private keys, extended keys, and fingerprints needed to access funds via another wallet. The design trades plausible deniability (archive filenames remain visible in the
https://relay.towardsliberty.com/cea51e0de135dade63c288938f7a99f71f5195c8c1aea700f86fe7ee3f989548.mp4