From e8bb50299de9554a3df1da511fe2e4a3c63a9348 Mon Sep 17 00:00:00 2001
From: Ezequiel Leanes <ezequiel.leanes@distillery.com>
Date: Sat, 3 Feb 2024 15:54:01 -0300
Subject: [PATCH] fix: set salt as empty (#232)

* fix: set salt as empty

* fix: resolve comment
---
 Sources/XMTPiOS/Crypto.swift | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/Sources/XMTPiOS/Crypto.swift b/Sources/XMTPiOS/Crypto.swift
index 4f3e7126..72c397a7 100644
--- a/Sources/XMTPiOS/Crypto.swift
+++ b/Sources/XMTPiOS/Crypto.swift
@@ -8,7 +8,7 @@ import Foundation
 public typealias CipherText = Xmtp_MessageContents_Ciphertext
 
 enum CryptoError: Error {
-	case randomBytes, combinedPayload, keyDerivationError, hmacSignatureError
+	case randomBytes, combinedPayload, hmacSignatureError
 }
 
 enum Crypto {
@@ -105,17 +105,12 @@ enum Crypto {
 	}
 	
 	static func hkdfHmacKey(secret: Data, info: Data) throws -> SymmetricKey {
-		do {
-			let salt = try secureRandomBytes(count: 32)
-			let key = HKDF<SHA256>.deriveKey(
-				inputKeyMaterial: SymmetricKey(data: secret),
-				salt: salt,
-				info: info,
-				outputByteCount: 32)
-			return key
-		} catch {
-			throw CryptoError.keyDerivationError
-		}
+		let key = HKDF<SHA256>.deriveKey(
+			inputKeyMaterial: SymmetricKey(data: secret),
+			salt: Data(),
+			info: info,
+			outputByteCount: 32)
+		return key
 	}
 	
 	static func generateHmacSignature(secret: Data, info: Data, message: Data) throws -> Data {