Add support for parsing transferable private keys with a primary public key and public subkeys

src/key/factory.js

@@ -51,15 +51,18 @@ const allowedKeyPackets = /*#__PURE__*/ util.constructAllowedPackets([
  * @throws if no key packet was found
  */
 function createKey(packetlist) {
-  for (const packet of packetlist) {
+  if (packetlist[0]?.constructor.tag === enums.packet.secretKey) {
-    switch (packet.constructor.tag) {
-      case enums.packet.secretKey:
     return new PrivateKey(packetlist);
-      case enums.packet.publicKey:
+  } else if (packetlist[0]?.constructor.tag === enums.packet.publicKey) {
+    if (packetlist.findPacket(enums.packet.secretSubkey)) {
+      return new PrivateKey(packetlist);
+    } else {
       return new PublicKey(packetlist);
     }
+  } else {
+    throw new Error('No primary key packet found');
   }
-  throw new Error('No key packet found');
+
 }
 
 
@@ -384,10 +387,10 @@ export async function readPrivateKey({ armoredKey, binaryKey, config, ...rest })
   const packetlist = await PacketList.fromBinary(input, allowedKeyPackets, config);
   const keyIndex = packetlist.indexOfTag(enums.packet.publicKey, enums.packet.secretKey);
   for (let i = 0; i < keyIndex.length; i++) {
-    if (packetlist[keyIndex[i]].constructor.tag === enums.packet.publicKey) {
+    const firstPrivateKeyList = packetlist.slice(keyIndex[i], keyIndex[i + 1]);
+    if (packetlist[keyIndex[i]].constructor.tag === enums.packet.publicKey && !firstPrivateKeyList.findPacket(enums.packet.secretSubkey)) {
       continue;
     }
-    const firstPrivateKeyList = packetlist.slice(keyIndex[i], keyIndex[i + 1]);
     return new PrivateKey(firstPrivateKeyList);
   }
   throw new Error('No secret key packet found');
@@ -471,10 +474,10 @@ export async function readPrivateKeys({ armoredKeys, binaryKeys, config }) {
   const packetlist = await PacketList.fromBinary(input, allowedKeyPackets, config);
   const keyIndex = packetlist.indexOfTag(enums.packet.publicKey, enums.packet.secretKey);
   for (let i = 0; i < keyIndex.length; i++) {
-    if (packetlist[keyIndex[i]].constructor.tag === enums.packet.publicKey) {
+    const oneKeyList = packetlist.slice(keyIndex[i], keyIndex[i + 1]);
+    if (packetlist[keyIndex[i]].constructor.tag === enums.packet.publicKey && !oneKeyList.findPacket(enums.packet.secretSubkey)) {
       continue;
     }
-    const oneKeyList = packetlist.slice(keyIndex[i], keyIndex[i + 1]);
     const newKey = new PrivateKey(oneKeyList);
     keys.push(newKey);
   }

src/key/key.js

@@ -49,13 +49,14 @@ class Key {
   /**
    * Transforms packetlist to structured key data
    * @param {PacketList} packetlist - The packets that form a key
-   * @param {Set<enums.packet>} disallowedPackets - disallowed packet tags
+   * @param {Boolean} expectPrivateKey - if a private key is expected, a SecretKeyPacket or SecretKeySubpacket must be present.
    */
-  packetListToStructure(packetlist, disallowedPackets = new Set()) {
+  packetListToStructure(packetlist, expectPrivateKey) {
     let user;
     let primaryKeyID;
     let subkey;
     let ignoreUntil;
+    let isPrivateKey;
 
     for (const packet of packetlist) {
 
@@ -78,7 +79,8 @@ class Key {
         if (!ignoreUntil.has(tag)) continue;
         ignoreUntil = null;
       }
-      if (disallowedPackets.has(tag)) {
+      isPrivateKey = isPrivateKey || tag === enums.packet.secretKey || tag === enums.packet.secretSubkey;
+      if (!expectPrivateKey && isPrivateKey) {
         throw new Error(`Unexpected packet type: ${tag}`);
       }
       switch (tag) {
@@ -151,6 +153,13 @@ class Key {
           break;
       }
     }
+
+    if (!this.keyPacket) {
+      throw new Error('Invalid key: missing primary key packet');
+    }
+    if (expectPrivateKey && !isPrivateKey) {
+      throw new Error('No secret key packet found');
+    }
   }
 
   /**

src/key/private_key.js

@@ -18,10 +18,7 @@ class PrivateKey extends PublicKey {
  */
   constructor(packetlist) {
     super();
-    this.packetListToStructure(packetlist, new Set([enums.packet.publicKey, enums.packet.publicSubkey]));
+    this.packetListToStructure(packetlist, true);
-    if (!this.keyPacket) {
-      throw new Error('Invalid key: missing private-key packet');
-    }
   }
 
   /**

src/key/public_key.js

@@ -32,10 +32,7 @@ class PublicKey extends Key {
     this.users = [];
     this.subkeys = [];
     if (packetlist) {
-      this.packetListToStructure(packetlist, new Set([enums.packet.secretKey, enums.packet.secretSubkey]));
+      this.packetListToStructure(packetlist, false);
-      if (!this.keyPacket) {
-        throw new Error('Invalid key: missing public-key packet');
-      }
     }
   }