SecKeyCopyKeyExchangeResult() function return an error, “kSecKeyKeyExchangeParameterRequestedSize is missing”

问题

I'm using Xcode11 Beta as IDE and Swift.

Below is my code, my code can work well on Xcode10.3, but it can't work on Xcode11. When I call the function SecKeyCopyKeyExchangeResult(), the stack always return an error, "kSecKeyKeyExchangeParameterRequestedSize is missing", but it's okay on Xcode10.3. I checked Apple Developer portal, haven't any clue on it.

`
func main() {

    testECDH()
}

private func testECDH(){
    generateKeyPair()
    let alicePublicKey = getPublicKey()
    let alicePrivateKey = getPrivateKey()
    print(alicePublicKey)
    print(alicePrivateKey)

    generateKeyPair()
    let bobPublicKey = getPublicKey()
    let bobPrivateKey = getPrivateKey()
    print(bobPublicKey)
    print(bobPrivateKey)

    let alice_bob_ecdhsecret = ecdhSecretCalculation(publicKey: alicePublicKey, privateKey: bobPrivateKey)!
    let bob_alice_ecdhsecret = ecdhSecretCalculation(publicKey: bobPublicKey, privateKey: alicePrivateKey)!

    os_log("alice_bob_ecdhsecret = %@", alice_bob_ecdhsecret)
    os_log("bob_alice_ecdhsecret = %@", bob_alice_ecdhsecret)
}

private func generateKeyPair(){
    let attributes: [String: Any] = [kSecAttrKeySizeInBits as String: 256,
                                     kSecAttrKeyType as String: kSecAttrKeyTypeECSECPrimeRandom,
                                     kSecPrivateKeyAttrs as String: [kSecAttrIsPermanent as String: false],
                                     kSecPublicKeyAttrs as String:[kSecAttrIsPermanent as String: false]]

    var error: Unmanaged<CFError>?

    privateKey = SecKeyCreateRandomKey(attributes as CFDictionary, &error)!

    if privateKey != nil {
        publicKey = SecKeyCopyPublicKey(privateKey!)
    }


}

private func getPrivateKey()->SecKey{
    return privateKey!
}

private func getPublicKey()->SecKey{
    return publicKey!
}

private func ecdhSecretCalculation(publicKey: SecKey, privateKey: SecKey) -> NSData?
{
    var error: Unmanaged<CFError>?

    let keyPairAttr:[String : Any] = [kSecAttrKeySizeInBits as String: 256,
                                      kSecAttrKeyType as String: kSecAttrKeyTypeECSECPrimeRandom,
                                      kSecPrivateKeyAttrs as String: [kSecAttrIsPermanent as String: false],
                                      kSecPublicKeyAttrs as String:[kSecAttrIsPermanent as String: false]]
    let algorithm:SecKeyAlgorithm = SecKeyAlgorithm.ecdhKeyExchangeStandardX963SHA256//ecdhKeyExchangeStandardX963SHA256

    let shared:CFData? = SecKeyCopyKeyExchangeResult(privateKey, algorithm, publicKey, keyPairAttr as! CFDictionary, &error)

    return shared
}`

回答1:

I just solve this issue by below code snippet

let keyPairAttr:[String : Any] = [kSecAttrKeySizeInBits as String: 256,

                                      SecKeyKeyExchangeParameter.requestedSize.rawValue as String: 32,
                                      kSecAttrKeyType as String: kSecAttrKeyTypeECSECPrimeRandom,
                                      kSecPrivateKeyAttrs as String: [kSecAttrIsPermanent as String: false],
                                      kSecPublicKeyAttrs as String:[kSecAttrIsPermanent as String: false]]
    let algorithm:SecKeyAlgorithm = SecKeyAlgorithm.ecdhKeyExchangeStandardX963SHA256//ecdhKeyExchangeStandardX963SHA256

    let shared:CFData? = SecKeyCopyKeyExchangeResult(privateKey, algorithm, publicKey, keyPairAttr as! CFDictionary, &error)

Please noticed that below is the code I added to solve this issue:

SecKeyKeyExchangeParameter.requestedSize.rawValue as String: 32,

来源：https://stackoverflow.com/questions/58007604/seckeycopykeyexchangeresult-function-return-an-error-kseckeykeyexchangeparam

标签

security

xcode11

ecdh