2 files changed, 75 insertions, 0 deletions
diff --git a/app/src/test/java/app/passwordstore/util/git/sshj/Ed25519KeyPairTest.kt b/app/src/test/java/app/passwordstore/util/git/sshj/Ed25519KeyPairTest.kt
new file mode 100644
index 00000000..34acae18
--- /dev/null
+++ b/app/src/test/java/app/passwordstore/util/git/sshj/Ed25519KeyPairTest.kt
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package app.passwordstore.util.git.sshj
+
+import java.security.Signature
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+import net.schmizz.sshj.common.Buffer
+import net.schmizz.sshj.common.KeyType
+import org.bouncycastle.jce.provider.BouncyCastleProvider
+
+class Ed25519KeyPairTest {
+
+  private fun hex(s: String) = s.chunked(2).map { it.toInt(16).toByte() }.toByteArray()
+
+  // RFC 8032, section 7.1, test 1. Wrapped keys store the 32-byte seed, so a seed must keep
+  // mapping to the same key pair across library changes.
+  private val seed = hex("9d61b19deffd5a60ba844af492ec2cc44449c5697b326919703bac031cae7f60")
+  private val publicKey = hex("d75a980182b10ab7d54bfed3c964073a0ee172f3daa62325af021a68f707511a")
+
+  @Test
+  fun derivesTheRfc8032PublicKeyFromTheSeed() {
+    val keyPair = ed25519KeyPair(seed)
+    assertEquals(KeyType.ED25519, KeyType.fromKey(keyPair.public))
+    val sshBlob = Buffer.PlainBuffer().putPublicKey(keyPair.public).compactData
+    // ssh-ed25519 wire format: string "ssh-ed25519", then string <32-byte public key>.
+    assertContentEquals(publicKey, sshBlob.copyOfRange(sshBlob.size - 32, sshBlob.size))
+  }
+
+  @Test
+  fun privateKeySignsForThePublicKey() {
+    val keyPair = ed25519KeyPair(seed)
+    val message = "hardenedpass".encodeToByteArray()
+    val signature =
+      Signature.getInstance("Ed25519", BouncyCastleProvider()).run {
+        initSign(keyPair.private)
+        update(message)
+        sign()
+      }
+    val verified =
+      Signature.getInstance("Ed25519", BouncyCastleProvider()).run {
+        initVerify(keyPair.public)
+        update(message)
+        verify(signature)
+      }
+    assertTrue(verified)
+  }
+}
diff --git a/app/src/test/java/app/passwordstore/util/git/sshj/SshjConfigTest.kt b/app/src/test/java/app/passwordstore/util/git/sshj/SshjConfigTest.kt
new file mode 100644
index 00000000..af6eee47
--- /dev/null
+++ b/app/src/test/java/app/passwordstore/util/git/sshj/SshjConfigTest.kt
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package app.passwordstore.util.git.sshj
+
+import kotlin.test.Test
+import kotlin.test.assertNull
+import net.schmizz.sshj.common.SecurityUtils
+
+class SshjConfigTest {
+
+  // Android Keystore keys have no encoding, so Bouncy Castle cannot sign with them. sshj must
+  // leave provider selection to the JCA, which hands Keystore keys to the AndroidKeyStore
+  // provider.
+  @Test
+  fun sshjDoesNotForceBouncyCastle() {
+    setUpBouncyCastleForSshj()
+    assertNull(SecurityUtils.getSecurityProvider())
+  }
+}