2 files changed, 25 insertions, 1 deletions
diff --git a/crypto/pgpainless/src/main/kotlin/app/passwordstore/crypto/KeyUtils.kt b/crypto/pgpainless/src/main/kotlin/app/passwordstore/crypto/KeyUtils.kt
index f85fe92c..311e9049 100644
--- a/crypto/pgpainless/src/main/kotlin/app/passwordstore/crypto/KeyUtils.kt
+++ b/crypto/pgpainless/src/main/kotlin/app/passwordstore/crypto/KeyUtils.kt
@@ -10,6 +10,7 @@ import app.passwordstore.crypto.PGPIdentifier.UserId
 import com.github.michaelbull.result.get
 import com.github.michaelbull.result.runCatching
 import org.bouncycastle.openpgp.PGPKeyRing
+import org.bouncycastle.openpgp.PGPSecretKeyRing
 import org.pgpainless.PGPainless
 import org.pgpainless.key.parsing.KeyRingReader
 
@@ -35,9 +36,13 @@ public object KeyUtils {
    */
   public fun tryGetEmail(key: PGPKey): UserId? {
     val keyRing = tryParseKeyring(key) ?: return null
-    return UserId(keyRing.publicKey.userIDs.next())
+    // A key may carry no user ID at all: next() threw NoSuchElementException there.
+    return keyRing.publicKey.userIDs.asSequence().firstOrNull()?.let(::UserId)
   }
 
+  /** True when [key] parses as a secret key ring, the only kind that can decrypt. */
+  public fun isSecretKey(key: PGPKey): Boolean = tryParseKeyring(key) is PGPSecretKeyRing
+
   /**
    * Tests if the given [key] can be used for encryption, which is a bare minimum necessity for the
    * app.
diff --git a/crypto/pgpainless/src/test/kotlin/app/passwordstore/crypto/KeyUtilsTest.kt b/crypto/pgpainless/src/test/kotlin/app/passwordstore/crypto/KeyUtilsTest.kt
index e6e3d7d1..3281c334 100644
--- a/crypto/pgpainless/src/test/kotlin/app/passwordstore/crypto/KeyUtilsTest.kt
+++ b/crypto/pgpainless/src/test/kotlin/app/passwordstore/crypto/KeyUtilsTest.kt
@@ -6,14 +6,18 @@
 package app.passwordstore.crypto
 
 import app.passwordstore.crypto.KeyUtils.isKeyUsable
+import app.passwordstore.crypto.KeyUtils.isSecretKey
+import app.passwordstore.crypto.KeyUtils.tryGetEmail
 import app.passwordstore.crypto.KeyUtils.tryGetId
 import app.passwordstore.crypto.KeyUtils.tryParseKeyring
 import app.passwordstore.crypto.TestUtils.AllKeys
 import app.passwordstore.crypto.TestUtils.getArmoredSecretKeyWithMultipleIdentities
 import kotlin.test.Test
 import kotlin.test.assertEquals
+import kotlin.test.assertFalse
 import kotlin.test.assertIs
 import kotlin.test.assertNotNull
+import kotlin.test.assertTrue
 import org.bouncycastle.openpgp.PGPSecretKeyRing
 
 class KeyUtilsTest {
@@ -37,4 +41,19 @@ class KeyUtilsTest {
       assertEquals(isUsable, isKeyUsable(key), "${allKeys.name} failed expectation:")
     }
   }
+
+  @Test
+  fun secretKeysAreTold() {
+    assertTrue(isSecretKey(PGPKey(AllKeys.ARMORED_SEC.keyMaterial)))
+    assertTrue(isSecretKey(PGPKey(AllKeys.GNUPG_OCB_SEC.keyMaterial)))
+    assertFalse(isSecretKey(PGPKey(AllKeys.ARMORED_PUB.keyMaterial)))
+    assertFalse(isSecretKey(PGPKey("not a key".encodeToByteArray())))
+  }
+
+  @Test
+  fun firstUserIdIsReturned() {
+    val key = PGPKey(getArmoredSecretKeyWithMultipleIdentities())
+    assertNotNull(tryGetEmail(key))
+    assertEquals(null, tryGetEmail(PGPKey("not a key".encodeToByteArray())))
+  }
 }