ios swift上的ECDH

Question

我正在开发一个iOS应用程序，我想实现ECDH的安全性。我使用此应用程序(https://github.com/DigitalLeaves/AsymmetricCrypto)生成一对密钥(私钥和公钥)，使用：

private let kAsymmetricCryptoManagerKeyType = kSecAttrKeyTypeEC
private let kAsymmetricCryptoManagerKeySize = 256
private let kAsymmetricCryptoManagerCypheredBufferSize = 128
private let kAsymmetricCryptoManagerSecPadding: SecPadding = .PKCS1

因此，我可以获取字符串形式的私钥和公钥，如下所示：

private key :3b3aef4e27c61e376bb1440f6a3077199d6d5ec665f6cd3595483a05ed96c498
public key X :3a405b5877d2939aea9dfb2995a89f4d63fca3c0cbb2a9d066fe67a08c499163
public key Y : 69bdbfc0ddea97ee03e85eb335db589cfcbee54b71f7fd74f6bc7344b5539ed6

这很好用。

现在，我想要的是执行ECDH，以在我生成的私钥和我(从另一个平台)获得的公钥之间生成共享密钥，就像字符串一样：

X: b1a2166411655482ad39630a480768dde4ccce5af4c53edec82496f17f0ddbfd
Y: e6dd01508da28f4f2295d9fee86239f88e8c5cbc94dbbb1f814b27c85d0d971a

因此，第一个问题是如何将字符串的最后两行转换为SecKey以生成公钥。

第二个问题是如何在我生成的私钥(作为SecKey)和我想在第一个问题中获得的新公钥之间执行ECDH。

下面是我用来生成密钥对的一小段代码：

 func createSecureKeyPair(_ completion: ((_ success: Bool, _ error: AsymmetricCryptoException?) -> Void)? = nil) {
        // private key parameters
        let privateKeyParams: [String: AnyObject] = [
            kSecAttrIsPermanent as String: true as AnyObject,
            kSecAttrApplicationTag as String: kAsymmetricCryptoManagerApplicationTag as AnyObject
        ]

        //public key parameters
        let publicKeyParams: [String: AnyObject] = [
            kSecAttrIsPermanent as String: true as AnyObject,
            kSecAttrApplicationTag as String: kAsymmetricCryptoManagerApplicationTag as AnyObject
        ]

        // global parameters for our key generation
        let parameters: [String: AnyObject] = [
            kSecAttrKeyType as String:          kAsymmetricCryptoManagerKeyType,
            kSecAttrKeySizeInBits as String:    kAsymmetricCryptoManagerKeySize as AnyObject,
            kSecPublicKeyAttrs as String:       publicKeyParams as AnyObject,
            kSecPrivateKeyAttrs as String:      privateKeyParams as AnyObject,
        ]

        // asynchronously generate the key pair and call the completion block
        DispatchQueue.global(qos: DispatchQoS.QoSClass.default).async { () -> Void in
            var pubKey, privKey: SecKey?
            let status = SecKeyGeneratePair(parameters as CFDictionary, &pubKey, &privKey)
            print("pub :",pubKey)

我想在这个网站上共享一个秘密:带有secp256r1参数的http://www-cs-students.stanford.edu/~tjw/jsbn/ecdh.html

提前谢谢。

Answer 1

我通过代码从x和y获得了你的SecKey：

<SecKeyRef curve type: kSecECCurveSecp384r1, algorithm id: 3, key type: ECPublicKey, version: 4, block size: 384 bits, y: 7BA75DD35E74F1D6B6F1FE1FDB6F7977D7DE7BCEB6DFD7FCF1EF1CE5C6DCF7875B6DBD5FF35E1BDBB73CE5DD1DF7BD5A, x: 6F56B6D7AEB8D75EB9E78F3669DDFDEB7D1AE3CD3BEBC75D7B871C71EE5A7F8739DDE75E73CDB8F7A7F5EDFD1D75B7DD, addr: 0x7fda4a60d510>

你可以关注我的文章。

https://medium.com/@vaibhav.pmeshram/creating-and-dismantling-ec-key-in-swift-f5bde8cb633f