fix(crypto): refuse to encrypt when a .gpg-id recipient key is missing

CryptoRepository.encrypt looked up every .gpg-id recipient and dropped
the ones it could not find, so an entry saved on a device that lacked
one recipient's key was encrypted to the others only. With a store
shared between a phone key and a smartcard key, entries created on the
phone could no longer be decrypted with the smartcard alone.

Fail with the lookup error instead (KeyNotFoundException names the
key), so the user imports the missing public key and saves again.

PasswordCreationActivity also ignored the Result of encrypt and wrote
the output buffer regardless: on any encryption failure it wrote an
empty .gpg file, overwriting the entry when editing, and committed it.
Show the error and leave the file untouched.

CryptoRepositoryTest covers both the missing-recipient failure and the
all-present success path, with keys generated by PGPainless (added as
an app test dependency).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

2 files changed, 24 insertions, 6 deletions

diff --git a/app/src/main/java/app/passwordstore/data/crypto/CryptoRepository.kt b/app/src/main/java/app/passwordstore/data/crypto/CryptoRepository.kt
index eb858006..61b63ea7 100644
--- a/app/src/main/java/app/passwordstore/data/crypto/CryptoRepository.kt
+++ b/app/src/main/java/app/passwordstore/data/crypto/CryptoRepository.kt
@@ -14,6 +14,8 @@ import app.passwordstore.crypto.PGPainlessCryptoHandler
 import app.passwordstore.injection.prefs.SettingsPreferences
 import app.passwordstore.util.coroutines.DispatcherProvider
 import app.passwordstore.util.settings.PreferenceKeys
+import com.github.michaelbull.result.andThen
+import com.github.michaelbull.result.combine
 import com.github.michaelbull.result.filterValues
 import com.github.michaelbull.result.map
 import com.github.michaelbull.result.mapBoth
@@ -64,7 +66,12 @@ constructor(
         PGPEncryptOptions.Builder()
           .withAsciiArmor(settings.getBoolean(PreferenceKeys.ASCII_ARMOR, false))
           .build()
-      val keys = identities.map { id -> pgpKeyManager.getKeyById(id) }.filterValues()
-      pgpCryptoHandler.encrypt(keys, content, out, encryptionOptions).map { out }
+      // Every recipient in .gpg-id must be present: silently dropping one would write an entry
+      // that the missing key's owner can no longer decrypt.
+      identities
+        .map { id -> pgpKeyManager.getKeyById(id) }
+        .combine()
+        .andThen { keys -> pgpCryptoHandler.encrypt(keys, content, out, encryptionOptions) }
+        .map { out }
     }
 }
diff --git a/app/src/main/java/app/passwordstore/ui/crypto/PasswordCreationActivity.kt b/app/src/main/java/app/passwordstore/ui/crypto/PasswordCreationActivity.kt
index b4fd21e5..6971c2e3 100644
--- a/app/src/main/java/app/passwordstore/ui/crypto/PasswordCreationActivity.kt
+++ b/app/src/main/java/app/passwordstore/ui/crypto/PasswordCreationActivity.kt
@@ -40,6 +40,7 @@ import app.passwordstore.util.extensions.unsafeLazy
 import app.passwordstore.util.extensions.viewBinding
 import app.passwordstore.util.settings.DirectoryStructure
 import app.passwordstore.util.settings.PreferenceKeys
+import com.github.michaelbull.result.getOrElse
 import com.github.michaelbull.result.onFailure
 import com.github.michaelbull.result.onSuccess
 import com.github.michaelbull.result.runCatching
@@ -378,10 +379,20 @@ class PasswordCreationActivity : BasePGPActivity() {
         runCatching {
             val result =
               withContext(dispatcherProvider.io()) {
-                val outputStream = ByteArrayOutputStream()
-                repository.encrypt(gpgIdentifiers, content.byteInputStream(), outputStream)
-                outputStream
-              }
+                  val outputStream = ByteArrayOutputStream()
+                  repository.encrypt(gpgIdentifiers, content.byteInputStream(), outputStream)
+                }
+                .getOrElse { e ->
+                  logcat(ERROR) { e.asLog("Failed to encrypt password file") }
+                  MaterialAlertDialogBuilder(this@PasswordCreationActivity)
+                    .setTitle(R.string.password_creation_file_fail_title)
+                    .setMessage(
+                      getString(R.string.password_creation_encrypt_fail_message, e.message)
+                    )
+                    .setPositiveButton(android.R.string.ok, null)
+                    .show()
+                  return@runCatching
+                }
             val passwordFile = Paths.get(path)
             // If we're not editing, this file should not already exist!
             // Additionally, if we were editing and the incoming and outgoing