diff --git a/Sources/Packages/Package.swift b/Sources/Packages/Package.swift
index 92dc60d..e508b60 100644
--- a/Sources/Packages/Package.swift
+++ b/Sources/Packages/Package.swift
@@ -43,7 +43,7 @@ let package = Package(
         ),
         .testTarget(
             name: "SecretKitTests",
-            dependencies: ["SecretKit", "SecureEnclaveSecretKit", "SmartCardSecretKit"],
+            dependencies: ["SecretKit", "SecretAgentKit", "SecureEnclaveSecretKit", "SmartCardSecretKit"],
             swiftSettings: swiftSettings,
         ),
         .target(
diff --git a/Sources/Packages/Tests/SecretKitTests/OpenSSHSignatureWriterTests.swift b/Sources/Packages/Tests/SecretKitTests/OpenSSHSignatureWriterTests.swift
index 51ff4a3..5c2a916 100644
--- a/Sources/Packages/Tests/SecretKitTests/OpenSSHSignatureWriterTests.swift
+++ b/Sources/Packages/Tests/SecretKitTests/OpenSSHSignatureWriterTests.swift
@@ -1,6 +1,7 @@
 import Foundation
 import Testing
 @testable import SecretKit
+@testable import SecretAgentKit
 @testable import SmartCardSecretKit
 
 @Suite struct OpenSSHSignatureWriterTests {
@@ -59,50 +60,23 @@ private extension OpenSSHSignatureWriterTests {
 
     enum ParseError: Error {
         case eof
-        case invalidLength
         case invalidAlgorithm
     }
 
-    struct Reader {
-        var data: Data
-        var offset: Int = 0
-
-        mutating func readU32() throws -> Int {
-            guard offset + 4 <= data.count else { throw ParseError.eof }
-            let value = data[offset..<offset + 4].reduce(0 as UInt32) { ($0 << 8) | UInt32($1) }
-            offset += 4
-            return Int(value)
-        }
-
-        mutating func readBytes(count: Int) throws -> Data {
-            guard count >= 0 else { throw ParseError.invalidLength }
-            guard offset + count <= data.count else { throw ParseError.eof }
-            let out = data[offset..<offset + count]
-            offset += count
-            return Data(out)
-        }
-
-        mutating func readString() throws -> Data {
-            let length = try readU32()
-            return try readBytes(count: length)
-        }
-    }
-
     func parseEcdsaSignatureMpints(from openSSHSignedData: Data) throws -> (r: Data, s: Data) {
-        var reader = Reader(data: openSSHSignedData)
+        let reader = OpenSSHReader(data: openSSHSignedData)
 
-        let outerLength = try reader.readU32()
-        guard outerLength == (openSSHSignedData.count - 4) else { throw ParseError.invalidLength }
+        // Prefix
+        _ = try reader.readNextBytes(as: UInt32.self)
 
-        let algorithm = try reader.readString()
-        guard String(data: algorithm, encoding: .utf8) == "ecdsa-sha2-nistp256" else {
+        let algorithm = try reader.readNextChunkAsString()
+        guard algorithm == "ecdsa-sha2-nistp256" else {
             throw ParseError.invalidAlgorithm
         }
 
-        let signatureChunk = try reader.readString()
-        var sigReader = Reader(data: signatureChunk)
-        let r = try sigReader.readString()
-        let s = try sigReader.readString()
+        let sigReader = try reader.readNextChunkAsSubReader()
+        let r = try sigReader.readNextChunk()
+        let s = try sigReader.readNextChunk()
         return (r, s)
     }