diff --git a/mail-message/data/src/main/kotlin/me/proton/core/mailmessage/data/extension/EmailPackage.kt b/mail-message/data/src/main/kotlin/me/proton/core/mailmessage/data/extension/EmailPackage.kt
index fec66cb76..b0c68136c 100644
--- a/mail-message/data/src/main/kotlin/me/proton/core/mailmessage/data/extension/EmailPackage.kt
+++ b/mail-message/data/src/main/kotlin/me/proton/core/mailmessage/data/extension/EmailPackage.kt
@@ -20,19 +20,20 @@ package me.proton.core.mailmessage.data.extension
 
 import me.proton.core.mailmessage.data.api.request.EmailPackage
 import me.proton.core.mailmessage.domain.entity.EncryptedPackage
+import me.proton.core.util.kotlin.toInt
 
 fun EncryptedPackage.toEmailPackage(): EmailPackage = EmailPackage(
     addresses = addresses.mapValues { entry ->
         when (val address = entry.value) {
             is EncryptedPackage.Address.Internal -> EmailPackage.Address(
-                type = address.type,
-                signature = address.signature,
+                type = address.packageType.type,
+                signature = address.signed.toInt(),
                 bodyKeyPacket = address.bodyKeyPacket,
                 attachmentKeyPackets = address.attachmentKeyPackets
             )
             is EncryptedPackage.Address.External -> EmailPackage.Address(
-                type = address.type,
-                signature = address.signature
+                type = address.packageType.type,
+                signature = address.signed.toInt()
             )
         }
     },
diff --git a/mail-message/domain/src/main/kotlin/me/proton/core/mailmessage/domain/Constants.kt b/mail-message/domain/src/main/kotlin/me/proton/core/mailmessage/domain/Constants.kt
new file mode 100644
index 000000000..e54a23d95
--- /dev/null
+++ b/mail-message/domain/src/main/kotlin/me/proton/core/mailmessage/domain/Constants.kt
@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2020 Proton Technologies AG
+ * This file is part of Proton Technologies AG and ProtonCore.
+ *
+ * ProtonCore is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * ProtonCore is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with ProtonCore.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+enum class PackageType(val type: Int) {
+    ProtonMail(1),
+    EncryptedOutside(2),
+    Cleartext(4),
+    PgpInline(8),
+    PgpMime(16),
+    ClearMime(32)
+}
diff --git a/mail-message/domain/src/main/kotlin/me/proton/core/mailmessage/domain/entity/EncryptedPackage.kt b/mail-message/domain/src/main/kotlin/me/proton/core/mailmessage/domain/entity/EncryptedPackage.kt
index c494c9762..dfed86595 100644
--- a/mail-message/domain/src/main/kotlin/me/proton/core/mailmessage/domain/entity/EncryptedPackage.kt
+++ b/mail-message/domain/src/main/kotlin/me/proton/core/mailmessage/domain/entity/EncryptedPackage.kt
@@ -18,6 +18,8 @@
 
 package me.proton.core.mailmessage.domain.entity
 
+import PackageType
+
 data class EncryptedPackage(
     val addresses: Map<String, Address>,
     val mimeType: String,
@@ -27,14 +29,14 @@ data class EncryptedPackage(
     val bodyKey: Key? = null,
 ) {
 
-    sealed class Address(val type: Int, val signature: Int) {
+    sealed class Address(val packageType: PackageType, val signed: Boolean) {
 
         data class Internal(
             val bodyKeyPacket: String,
             val attachmentKeyPackets: List<String>
-        ) : Address(1, 1) // TODO
+        ) : Address(PackageType.ProtonMail, true)
 
-        object External : Address(4, 0) // TODO
+        object External : Address(PackageType.Cleartext, false)
     }
 
     data class Key(