This is a simple library to encrypt and decrypt small amount of data such as passwords.

• Supports down to Android API 18
• Exposes only two methods: Encrypt and Decrypt
• No useless boilerplate
• Uses AndroidKeyStore to store the keys
• Fixed cryptographic algorithms
  • RSA for 18 <= API <= 22 and optionally also for API >= 23 (if you set forceAsymmetric = true in initialization))
  • AES for API >= 23

• Init the library

Crypto.init(context, "keys_alias")

• Use the library

val helper = EncryptionHelper.getInstance()
val encrypted = helper.encrypt("some_text")
val decrypted = helper.decrypt(encrypted)

• More init configuration
  • Algorithm
  • Provider
  • Transformation
• Resiliency to AndroidKeyStore keys deletion
• Recover from exception
• Other features I'm not yet aware

On API level lower than 21 keys might be deleted when user change the display's security mechanism (screen lock) Use with caution and only if losing your keys or not being able to recover the encrypted data are not critical for you.

Parts of the code are freely inspired by the Security Workshop Sample