CacheWord: Passphrase Caching and Management

CacheWord is an Android library project for passphrase caching and management. It helps app developers securely generate, store, and access secrets derived from a user’s passphrase. It is designed to work easily with IOCipher and SQLCipher-for-Android, but it can be used any time an app needs to manage a password. Broadly speaking this library assists developers with two related problems:

  1. Secrets Management: how the secret key material for your app is generated, stored, and accessed
  2. Passphrase Caching: store the passphrase in memory to avoid constantly prompting the user

CacheWord manages key derivation, verification, persistence, passphrase resetting, and caching secret key material in memory.

Features

  • Strong key derivation (PBKDF2)
  • Dynamic KDF iteration count based on CPU speed
  • Secure secret storage (AES-256 GCM)
  • Persistent notification: informs the user the app data is unlocked
  • Configurable timeout: after a specified time of inactivity the app locks itself
  • Manual clearing: the user can forcibly lock the application

Source Code Repository