将 SecKey 从 iOS 导出到 watchOS [英] Exporting SecKey from iOS to watchOS

问题描述

我正在尝试在我的 iOS 应用与其 watchOS 等效应用之间同步私有非对称密钥.我尝试使用 SecKeyCopyExternalRepresentation 将其导出为 CFData，然后使用 WatchConnectivity 将其发送到手表.但是，当它到达手表时，我无法将数据转换回 SecKey.我尝试使用 SecKeyCreateWithData 试图重新创建它，但它似乎只适用于对称密钥，因为当我尝试它时它使手表应用程序崩溃.有什么想法吗?

I am trying to sync up private asymmetric keys between my iOS app and its watchOS equivalent. I have tried using SecKeyCopyExternalRepresentation to export it out as CFData and then send it to the watch using WatchConnectivity. However when it gets to the watch I have no way of converting the Data back into a SecKey. I tried using SecKeyCreateWithData in an attempt to recreate it, but it seems that that only works with symmetric keys, for when I tried it it crashed the watch app. Any ideas?

iOS 代码:

func sendSharedKeyPair(keyPair: (publicKey: SecKey, privateKey: SecKey)) {
    var error: Unmanaged<CFError>?

    let publicKeyData = SecKeyCopyExternalRepresentation(keyPair.publicKey, &error)
    if let error = error {
        return print("Error sending shared key: \(error)")
    }
    let privateKeyData = SecKeyCopyExternalRepresentation(keyPair.privateKey, &error)
    if let error = error {
        return print("Error sending shared key: \(error)")
    }

    if let publicKeyData = publicKeyData, let privateKeyData = privateKeyData {
        session.sendMessage(["requestedCommand": WatchControllerCommands.sendSharedKeyPair.rawValue, "keyPair": ["publicKey": publicKeyData, "privateKey": privateKeyData]], replyHandler: nil, errorHandler: { error in
            print(error)
        })
    }


}

watchOS 代码:

watchOS Code:

func session(_ session: WCSession, didReceiveMessage message: [String : Any]) {
    guard let requestedCommand = (message["requestedCommand"] as? String).flatMap({ WatchControllerCommands(rawValue: $0) }), requestedCommand == .sendSharedKeyPair else { return }

    guard let publicKeyData = (message["keyPair"] as? [String: Any])?["publicKey"].flatMap({ $0 as? Data }), let privateKeyData = (message["keyPair"] as? [String: Any])?["privateKey"].flatMap({ $0 as? Data }) else { return print("Couldn't parse keys") }

    let publicTag = "myAppTag"
    let privateTag = publicTag + ".private"

    let privateAttributes = [String(kSecAttrIsPermanent): true,
                             String(kSecAttrApplicationTag): privateTag] as [String : Any]
    let publicAttributes = [String(kSecAttrIsPermanent): true,
                            String(kSecAttrApplicationTag): publicTag] as [String : Any]

    var error: Unmanaged<CFError>?
    let publicCFData = publicKeyData as CFData
    let privateCFData = privateKeyData as CFData
    let publicCFDict = publicAttributes as CFDictionary
    let privateCFDict = privateAttributes as CFDictionary
    SecKeyCreateWithData(publicCFData, publicCFDict, &error)
    if let error = error {
        print(error)
    }
    SecKeyCreateWithData(privateCFData, privateCFDict, &error)
    if let error = error {
        print(error)
    }
}

推荐答案

来自 SecKeyCreateWithData 的标题文档:

@param attributes 包含描述键的属性的字典要进口.该字典中的键是 kSecAttr* 常量来自 SecItem.h.强制性属性是: * kSecAttrKeyType *kSecAttrKeyClass * kSecAttrKeySizeInBits

@param attributes Dictionary containing attributes describing the key to be imported. The keys in this dictionary are kSecAttr* constants from SecItem.h. Mandatory attributes are: * kSecAttrKeyType * kSecAttrKeyClass * kSecAttrKeySizeInBits

您的代码仅定义了 kSecAttrIsPermanent 和 kSecAttrApplicationTag 属性.

Your code only defines kSecAttrIsPermanent and kSecAttrApplicationTag attributes.

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