From 2dea73c584fb7dcab175cc07c3842b6e8a48b2ae Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Wed, 2 Apr 2025 13:45:21 +0200
Subject: [PATCH] KeySpecBuilder: Expose API for overriding default AEAD
 algorithms and features

---
 .../key/generation/KeySpecBuilder.kt          | 24 ++++++++++++++-----
 .../key/generation/KeySpecBuilderInterface.kt |  6 +++++
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/pgpainless-core/src/main/kotlin/org/pgpainless/key/generation/KeySpecBuilder.kt b/pgpainless-core/src/main/kotlin/org/pgpainless/key/generation/KeySpecBuilder.kt
index 2ed50ffa..21cf5ec0 100644
--- a/pgpainless-core/src/main/kotlin/org/pgpainless/key/generation/KeySpecBuilder.kt
+++ b/pgpainless-core/src/main/kotlin/org/pgpainless/key/generation/KeySpecBuilder.kt
@@ -12,8 +12,7 @@ import org.pgpainless.signature.subpackets.SelfSignatureSubpackets
 import org.pgpainless.signature.subpackets.SignatureSubpackets
 import org.pgpainless.signature.subpackets.SignatureSubpacketsUtil
 
-class KeySpecBuilder
-constructor(
+class KeySpecBuilder(
     private val type: KeyType,
     private val keyFlags: List<KeyFlag>,
 ) : KeySpecBuilderInterface {
@@ -27,6 +26,7 @@ constructor(
     private var preferredSymmetricAlgorithms: Set<SymmetricKeyAlgorithm>? =
         algorithmSuite.symmetricKeyAlgorithms
     private var preferredAEADAlgorithms: Set<AEADCipherMode>? = algorithmSuite.aeadAlgorithms
+    private var features: Set<Feature>? = algorithmSuite.features
     private var keyCreationDate: Date? = null
 
     constructor(type: KeyType, vararg keyFlags: KeyFlag) : this(type, listOf(*keyFlags))
@@ -37,11 +37,13 @@ constructor(
 
     override fun overridePreferredCompressionAlgorithms(
         vararg algorithms: CompressionAlgorithm
-    ): KeySpecBuilder = apply { this.preferredCompressionAlgorithms = algorithms.toSet() }
+    ): KeySpecBuilder = apply {
+        this.preferredCompressionAlgorithms = if (algorithms.isEmpty()) null else algorithms.toSet()
+    }
 
     override fun overridePreferredHashAlgorithms(vararg algorithms: HashAlgorithm): KeySpecBuilder =
         apply {
-            this.preferredHashAlgorithms = algorithms.toSet()
+            this.preferredHashAlgorithms = if (algorithms.isEmpty()) null else algorithms.toSet()
         }
 
     override fun overridePreferredSymmetricKeyAlgorithms(
@@ -50,7 +52,17 @@ constructor(
         require(!algorithms.contains(SymmetricKeyAlgorithm.NULL)) {
             "NULL (unencrypted) is an invalid symmetric key algorithm preference."
         }
-        this.preferredSymmetricAlgorithms = algorithms.toSet()
+        this.preferredSymmetricAlgorithms = if (algorithms.isEmpty()) null else algorithms.toSet()
+    }
+
+    override fun overridePreferredAEADAlgorithms(
+        vararg algorithms: AEADCipherMode
+    ): KeySpecBuilder = apply {
+        this.preferredAEADAlgorithms = if (algorithms.isEmpty()) null else algorithms.toSet()
+    }
+
+    override fun overrideFeatures(vararg features: Feature): KeySpecBuilder = apply {
+        this.features = if (features.isEmpty()) null else features.toSet()
     }
 
     override fun setKeyCreationDate(creationDate: Date): KeySpecBuilder = apply {
@@ -65,7 +77,7 @@ constructor(
                 preferredHashAlgorithms?.let { setPreferredHashAlgorithms(it) }
                 preferredSymmetricAlgorithms?.let { setPreferredSymmetricKeyAlgorithms(it) }
                 preferredAEADAlgorithms?.let { setPreferredAEADCiphersuites(it) }
-                setFeatures(Feature.MODIFICATION_DETECTION)
+                features?.let { setFeatures(*it.toTypedArray()) }
             }
             .let { KeySpec(type, hashedSubpackets as SignatureSubpackets, false, keyCreationDate) }
     }
diff --git a/pgpainless-core/src/main/kotlin/org/pgpainless/key/generation/KeySpecBuilderInterface.kt b/pgpainless-core/src/main/kotlin/org/pgpainless/key/generation/KeySpecBuilderInterface.kt
index 7fb767e4..956a70b0 100644
--- a/pgpainless-core/src/main/kotlin/org/pgpainless/key/generation/KeySpecBuilderInterface.kt
+++ b/pgpainless-core/src/main/kotlin/org/pgpainless/key/generation/KeySpecBuilderInterface.kt
@@ -5,7 +5,9 @@
 package org.pgpainless.key.generation
 
 import java.util.*
+import org.pgpainless.algorithm.AEADCipherMode
 import org.pgpainless.algorithm.CompressionAlgorithm
+import org.pgpainless.algorithm.Feature
 import org.pgpainless.algorithm.HashAlgorithm
 import org.pgpainless.algorithm.SymmetricKeyAlgorithm
 
@@ -21,6 +23,10 @@ interface KeySpecBuilderInterface {
         vararg algorithms: SymmetricKeyAlgorithm
     ): KeySpecBuilder
 
+    fun overridePreferredAEADAlgorithms(vararg algorithms: AEADCipherMode): KeySpecBuilder
+
+    fun overrideFeatures(vararg features: Feature): KeySpecBuilder
+
     fun setKeyCreationDate(creationDate: Date): KeySpecBuilder
 
     fun build(): KeySpec