From 6d89eb9e76e42ea5ccc24c28ccde8770512fc0ef Mon Sep 17 00:00:00 2001
From: Chris Duncan <chris@zoso.dev>
Date: Fri, 8 Aug 2025 13:53:20 -0700
Subject: [PATCH] Require wallet type as additional metadata to decrypt.

---
 src/lib/safe.ts   | 35 ++++++++++++++++++++++++++---------
 src/lib/wallet.ts |  1 +
 2 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/src/lib/safe.ts b/src/lib/safe.ts
index 8a97124..6aecb1e 100644
--- a/src/lib/safe.ts
+++ b/src/lib/safe.ts
@@ -69,7 +69,7 @@ export class Safe {
 						break
 					}
 					case 'unlock': {
-						result = await this.unlock(key, iv, encrypted)
+						result = await this.unlock(type, key, iv, encrypted)
 						break
 					}
 					case 'update': {
@@ -209,8 +209,11 @@ export class Safe {
 	/**
 	* Decrypts the input and sets the seed and, if it is included, the mnemonic.
 	*/
-	static async unlock (key?: CryptoKey, iv?: ArrayBuffer, encrypted?: ArrayBuffer): Promise<NamedData<boolean>> {
+	static async unlock (type?: string, key?: CryptoKey, iv?: ArrayBuffer, encrypted?: ArrayBuffer): Promise<NamedData<boolean>> {
 		try {
+			if (type == null) {
+				throw new TypeError('Wallet type is required')
+			}
 			if (key == null) {
 				throw new TypeError('Wallet password is required')
 			}
@@ -220,7 +223,7 @@ export class Safe {
 			if (encrypted == null) {
 				throw new TypeError('Wallet encrypted data is required')
 			}
-			const { seed, mnemonic } = await this.#decryptWallet(key, iv, encrypted)
+			const { seed, mnemonic } = await this.#decryptWallet(type, key, iv, encrypted)
 			if (!(seed instanceof ArrayBuffer)) {
 				throw new TypeError('Invalid seed')
 			}
@@ -312,11 +315,21 @@ export class Safe {
 		return await crypto.subtle.deriveKey(derivationAlgorithm, derivationKey, derivedKeyType, false, [purpose])
 	}
 
-	static async #decryptWallet (key: CryptoKey, iv: ArrayBuffer, encrypted: ArrayBuffer): Promise<NamedData<string | ArrayBuffer>> {
-		const decrypted = await crypto.subtle.decrypt({ name: 'AES-GCM', iv }, key, encrypted)
-		const decoded = JSON.parse(bytes.toUtf8(new Uint8Array(decrypted)))
-		const seed = hex.toBuffer(decoded.seed)
-		const mnemonic = decoded.mnemonic
+	static async #decryptWallet (type: string, key: CryptoKey, iv: ArrayBuffer, encrypted: ArrayBuffer): Promise<NamedData<string | ArrayBuffer>> {
+		let decrypted, decoded, parsed
+
+		const additionalData = utf8.toBytes(type)
+		decrypted = new Uint8Array(await crypto.subtle.decrypt({ name: 'AES-GCM', iv, additionalData }, key, encrypted))
+		decoded = bytes.toUtf8(decrypted)
+		bytes.erase(decrypted)
+		decrypted = undefined
+
+		parsed = JSON.parse(decoded)
+		decoded = undefined
+
+		const seed = hex.toBuffer(parsed.seed)
+		const mnemonic = parsed.mnemonic
+		parsed = parsed.seed = parsed.mnemonic = undefined
 		return { seed, mnemonic }
 	}
 
@@ -342,6 +355,9 @@ export class Safe {
 	}
 
 	static async #encryptWallet (key: CryptoKey): Promise<NamedData<ArrayBuffer>> {
+		if (this.#type == null) {
+			throw new Error('Invalid wallet type')
+		}
 		if (this.#seed == null) {
 			throw new Error('Wallet seed not found')
 		}
@@ -352,8 +368,9 @@ export class Safe {
 
 		// restrict iv to 96 bits per GCM best practice
 		const iv = crypto.getRandomValues(new Uint8Array(12)).buffer
+		const additionalData = utf8.toBytes(this.#type)
 		const encoded = utf8.toBytes(JSON.stringify(data))
-		const encrypted = await crypto.subtle.encrypt({ name: 'AES-GCM', iv }, key, encoded)
+		const encrypted = await crypto.subtle.encrypt({ name: 'AES-GCM', iv, additionalData }, key, encoded)
 		return { iv, encrypted }
 	}
 
diff --git a/src/lib/wallet.ts b/src/lib/wallet.ts
index 354fdc4..bb5c12a 100644
--- a/src/lib/wallet.ts
+++ b/src/lib/wallet.ts
@@ -404,6 +404,7 @@ export class Wallet {
 			const { iv, salt, encrypted } = await Wallet.#get(this.#id)
 			const { isUnlocked } = await this.#safe.request<boolean>({
 				action: 'unlock',
+				type: this.#type,
 				password: utf8.toBuffer(password),
 				iv,
 				keySalt: salt,
-- 
2.47.3