Ole-Morten Duesund
8f5b18cf68
Milestone 5. One BackupManager entry point so export, import and auto-backup share the same serializer and crypto by construction. Explicit DTOs decouple the backup contract from the Room schema. JCE baseline (PBKDF2-HMAC-SHA256 600k → AES-256-GCM) behind the BackupCrypto interface with format auto-detection on decrypt; age lands behind the same interface in milestone 6. SigV4 signer verified against AWS's published documentation example signature. Settings in SharedPreferences encrypted under a non-exportable AndroidKeyStore key — replaces the now fully deprecated androidx security-crypto with the same construction (~70 lines, zero deps); threat-model comments state plainly that the stored auto-backup passphrase only protects against bucket compromise. WorkManager daily periodic job, inexact by design. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
54 lines
1.9 KiB
Kotlin
54 lines
1.9 KiB
Kotlin
package no.naiv.meddetsamme.backup
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import javax.crypto.AEADBadTagException
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import org.junit.Assert.assertArrayEquals
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import org.junit.Assert.assertEquals
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import org.junit.Assert.assertFalse
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import org.junit.Assert.assertThrows
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import org.junit.Assert.assertTrue
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import org.junit.Test
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class JceBackupCryptoTest {
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private val plaintext = """{"version":1,"medications":[]}""".toByteArray()
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private val passphrase = "korrekt hest batteri stift".toCharArray()
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@Test
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fun `round trip with correct passphrase`() {
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val ct = JceBackupCrypto.encrypt(plaintext, passphrase)
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assertArrayEquals(plaintext, JceBackupCrypto.decrypt(ct, passphrase))
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}
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@Test
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fun `wrong passphrase fails authentication, not garbage output`() {
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val ct = JceBackupCrypto.encrypt(plaintext, passphrase)
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assertThrows(AEADBadTagException::class.java) {
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JceBackupCrypto.decrypt(ct, "feil passord".toCharArray())
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}
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}
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@Test
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fun `tampered ciphertext fails authentication`() {
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val ct = JceBackupCrypto.encrypt(plaintext, passphrase)
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ct[ct.size - 5] = (ct[ct.size - 5].toInt() xor 1).toByte()
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assertThrows(AEADBadTagException::class.java) {
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JceBackupCrypto.decrypt(ct, passphrase)
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}
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}
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@Test
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fun `format detection by magic`() {
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val ct = JceBackupCrypto.encrypt(plaintext, passphrase)
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assertTrue(JceBackupCrypto.matches(ct))
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assertFalse(JceBackupCrypto.matches(plaintext))
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assertEquals(JceBackupCrypto, BackupCrypto.detect(ct))
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assertEquals(null, BackupCrypto.detect(plaintext))
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}
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@Test
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fun `fresh salt and IV every time`() {
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val a = JceBackupCrypto.encrypt(plaintext, passphrase)
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val b = JceBackupCrypto.encrypt(plaintext, passphrase)
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assertFalse(a.contentEquals(b)) // deterministic encryption would leak equality
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}
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}
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