Description

An app that demonstrates usages of Android Keystore API to store keys. The keys can be used to verify the signature and for encryption and decryption.

Usages

Run ./gradlew androidConnectedTest to verify the program is working. You need to connect your computer to an emulator or real device to execute the test.

There are three demo classes with three accompanying test classes:

1. VerifyWithKeyPair and VerifyWithKeyPairTest
2. EncryptDecrypt and EncryptDecryptTest
3. EncryptDecrypt2 and EncryptDecryptTest2

VerifyWithKeyPair uses SHA256withECDSA cipher to sign and verify the text.

VerifyWithKeyPair.sign(data: ByteArray) : ByteArray
VerifyWithKeyPair.verify(signature: ByteArray, data: ByteArray) : Boolean

EncryptDecrypt uses "AES/CBC/PKCS7Padding" for encryption and decryption, while uses EncryptDecrypt2 "AES/GCM/NoPadding" for encryption and decryption.

EncryptDecrypt.encrypt(data: ByteArray): Pair<ByteArray, ByteArray>
EncryptDecrypt.decrypt(data: ByteArray, iv: ByteArray): ByteArray
EncryptDecrypt.encrypt(data: ByteArray): Pair<ByteArray, ByteArray>
EncryptDecrypt2.decrypt(data: ByteArray, iv: ByteArray): ByteArray

Run this command to see the differences between EncryptDecrypt and EncryptDecrypt2

git diff \
HEAD:app/src/main/java/com/github/androidkeystoredemo/EncryptDecrypt.kt \
HEAD:app/src/main/java/com/github/androidkeystoredemo/EncryptDecrypt2.kt

Both EncryptDecrypt and EncryptDecrypt2 uses IV (Initialization Vector), to ensure that the same input always generates different output.