Swift 4 中的 HMAC SHA256

Question

我有一个字符串和一个密钥，我想从中生成一个 HMAC SHA256。虽然我使用 2 个库

IDZSwiftCommonCrypto 和 CryptoSwift

和this answer

没有什么对我真正有用。我的事实来源是这两个网站

https://myeasywww.appspot.com/utility/free/online/Crypt_Decrypt-MD5-AES-HMAC-SHA-DES-RABBIT/en?command=UTILITY&ID=2

和

https://www.freeformatter.com/hmac-generator.html#ad-output

他们总是为我的情况生成正确的哈希键。 知道什么可以在这里工作吗？一些代码示例

对于 IDZSwiftCommonCrypto

func getHMacSHA256(forMessage message: String, key: String) -> String? {
    let hMacVal = HMAC(algorithm: HMAC.Algorithm.sha256, key: key).update(string: message)?.final()
    if let encryptedData = hMacVal {
        let decData = NSData(bytes: encryptedData, length: Int(encryptedData.count))
        let base64String = decData.base64EncodedString(options: .lineLength64Characters)
        print("base64String: \(base64String)")
        return base64String
    } else {
        return nil
    }
}

对于 CryptoSwift

    let password: Array<UInt8> = Array(payload.utf8)
    let salt: Array<UInt8> = Array("somekey".utf8)

    let signedBody = try? HKDF(password: password, salt: salt, variant: .sha256).calculate()

但没有什么比真相的来源更有效。有什么想法吗？

Answer 1

如果您的目标是 iOS 13.0+ 或 macOS 10.15+，请使用 Apple 的 CryptoKit

import CryptoKit

let secretString = "my-secret"
let key = SymmetricKey(data: Data(secretString.utf8))

let string = "An apple a day keeps anyone away, if you throw it hard enough"

let signature = HMAC<SHA256>.authenticationCode(for: Data(string.utf8), using: key)
print(Data(signature).map { String(format: "%02hhx", $0) }.joined()) // 1c161b971ab68e7acdb0b45cca7ae92d574613b77fca4bc7d5c4effab89dab67

Answer 2

我一直在用这个：

import Foundation

enum CryptoAlgorithm {
    case MD5, SHA1, SHA224, SHA256, SHA384, SHA512

    var HMACAlgorithm: CCHmacAlgorithm {
        var result: Int = 0
        switch self {
        case .MD5:      result = kCCHmacAlgMD5
        case .SHA1:     result = kCCHmacAlgSHA1
        case .SHA224:   result = kCCHmacAlgSHA224
        case .SHA256:   result = kCCHmacAlgSHA256
        case .SHA384:   result = kCCHmacAlgSHA384
        case .SHA512:   result = kCCHmacAlgSHA512
        }
        return CCHmacAlgorithm(result)
    }

    var digestLength: Int {
        var result: Int32 = 0
        switch self {
        case .MD5:      result = CC_MD5_DIGEST_LENGTH
        case .SHA1:     result = CC_SHA1_DIGEST_LENGTH
        case .SHA224:   result = CC_SHA224_DIGEST_LENGTH
        case .SHA256:   result = CC_SHA256_DIGEST_LENGTH
        case .SHA384:   result = CC_SHA384_DIGEST_LENGTH
        case .SHA512:   result = CC_SHA512_DIGEST_LENGTH
        }
        return Int(result)
    }
}

extension String {

    func hmac(algorithm: CryptoAlgorithm, key: String) -> String {
        let str = self.cString(using: String.Encoding.utf8)
        let strLen = Int(self.lengthOfBytes(using: String.Encoding.utf8))
        let digestLen = algorithm.digestLength
        let result = UnsafeMutablePointer<CUnsignedChar>.allocate(capacity: digestLen)
        let keyStr = key.cString(using: String.Encoding.utf8)
        let keyLen = Int(key.lengthOfBytes(using: String.Encoding.utf8))

        CCHmac(algorithm.HMACAlgorithm, keyStr!, keyLen, str!, strLen, result)

        let digest = stringFromResult(result: result, length: digestLen)

        result.deallocate(capacity: digestLen)

        return digest
    }

    private func stringFromResult(result: UnsafeMutablePointer<CUnsignedChar>, length: Int) -> String {
        let hash = NSMutableString()
        for i in 0..<length {
            hash.appendFormat("%02x", result[i])
        }
        return String(hash).lowercased()
    }
}

您需要将 #import <CommonCrypto/CommonHMAC.h> 添加到您的 Objective-C 桥接头。

来源：@thevalyreangroup on this github thread

Answer 3

你用 CryptoSwift 做错了。

对于未来的读者，这里是如何做到这一点：

let result = try! HMAC(key: key, variant: .sha256).authenticate(message.bytes)

Answer 4

HMAC 加密的 Swift 4.2 解决方案

不久前我遇到了同样的问题，所以我写了一个简单的框架，可以在所有平台上使用 Swift - iOS ma​​cOS 和 tvOS

它叫做 EasyCrypt，你可以在这里找到它： https://github.com/lukszar/EasyCrypt

此框架允许您使用 HMAC 算法使用您的密钥加密消息。 用法很简单，如下：

let crypto = EasyCrypt(secret: "mySecretKey", algorithm: .sha256)
let result = crypto.hash("This is very secret text to encrypt")
let otherResult = crypto.hash("This is another secret text to encrypt")

print("result: ", result)
print("otherResult: ", otherResult)

您可以使用 Carthage 快速安装。在项目内部，您可以找到 Playground 以进行演示，并附有说明。