Question

在使用像CommonCrypto，CryptoSwift这样的库之后，我尝试在Swift 4中生成hash_hmac（'sha256'，$ key，$ secret_key）等效的php函数，但没有成功。我需要这些API身份验证功能，使用Alamofire库，这是一个很棒的库。由于我使用Swift 4，因此与其他Swift库的兼容性并不是那么好。即使使用具有Swift 4最新版本（0.7.1）的CryptoSwift，我仍然会遇到很多兼容性错误 enter image description here

Answer 1

Swift 3/4：

HMAC与MD5，SHA1，SHA224，SHA256，SHA384，SHA512（Swift 3）

这些函数将使用八种加密哈希算法之一对String或Data输入进行散列。

name参数将散列函数名称指定为String 支持的功能有MD5，SHA1，SHA224，SHA256，SHA384和SHA512

此示例需要Common Crypto
项目必须有一个桥接标题：
#import <CommonCrypto/CommonCrypto.h>
将Security.framework添加到项目中。

这些函数采用哈希名称，要散列的消息，密钥并返回摘要：

hashName: name of a hash function as String  
message:  message as Data  
key:      key as Data  
returns:  digest as Data

func hmac(hashName:String, message:Data, key:Data) -> Data? {
    let algos = ["SHA1":   (kCCHmacAlgSHA1,   CC_SHA1_DIGEST_LENGTH),
                 "MD5":    (kCCHmacAlgMD5,    CC_MD5_DIGEST_LENGTH),
                 "SHA224": (kCCHmacAlgSHA224, CC_SHA224_DIGEST_LENGTH),
                 "SHA256": (kCCHmacAlgSHA256, CC_SHA256_DIGEST_LENGTH),
                 "SHA384": (kCCHmacAlgSHA384, CC_SHA384_DIGEST_LENGTH),
                 "SHA512": (kCCHmacAlgSHA512, CC_SHA512_DIGEST_LENGTH)]
    guard let (hashAlgorithm, length) = algos[hashName]  else { return nil }
    var macData = Data(count: Int(length))

    macData.withUnsafeMutableBytes {macBytes in
        message.withUnsafeBytes {messageBytes in
            key.withUnsafeBytes {keyBytes in
                CCHmac(CCHmacAlgorithm(hashAlgorithm),
                       keyBytes,     key.count,
                       messageBytes, message.count,
                       macBytes)
            }
        }
    }
    return macData

}

hashName: name of a hash function as String
message:  message as String
key:      key as String
returns:  digest as Data

func hmac(hashName:String, message:String, key:String) -> Data? {
    let messageData = message.data(using:.utf8)!
    let keyData = key.data(using:.utf8)!
    return hmac(hashName:hashName, message:messageData, key:keyData)
}

hashName: name of a hash function as String  
message:  message as String  
key:      key as Data  
returns:  digest as Data

func hmac(hashName:String, message:String, key:Data) -> Data? {
    let messageData = message.data(using:.utf8)!
    return hmac(hashName:hashName, message:messageData, key:key)
}

//示例

let clearString = "clearData0123456"
let keyString   = "keyData8901234562"
let clearData   = clearString.data(using:.utf8)!
let keyData     = keyString.data(using:.utf8)!
print("clearString: \(clearString)")
print("keyString:   \(keyString)")
print("clearData: \(clearData as NSData)")
print("keyData:   \(keyData as NSData)")

let hmacData1 = hmac(hashName:"SHA1", message:clearData, key:keyData)
print("hmacData1: \(hmacData1! as NSData)")

let hmacData2 = hmac(hashName:"SHA1", message:clearString, key:keyString)
print("hmacData2: \(hmacData2! as NSData)")

let hmacData3 = hmac(hashName:"SHA1", message:clearString, key:keyData)
print("hmacData3: \(hmacData3! as NSData)")

输出：

clearString: clearData0123456
keyString:   keyData8901234562
clearData: <636c6561 72446174 61303132 33343536>
keyData:   <6b657944 61746138 39303132 33343536 32>

hmacData1: <bb358f41 79b68c08 8e93191a da7dabbc 138f2ae6>
hmacData2: <bb358f41 79b68c08 8e93191a da7dabbc 138f2ae6>
hmacData3: <bb358f41 79b68c08 8e93191a da7dabbc 138f2ae6>

Answer 2

首先，直接使用SHA512可能会更好，因为使用GPU可以很容易地破解SHA，因此提高内存容量并不是一个坏主意。

其次，使用CommonCrypto实际上非常容易生成HMAC，这是我使用的实现：

static func hmac(_ secretKey: inout [UInt8], cipherText: inout [UInt8], algorithm: CommonCrypto.HMACAlgorithm = .sha512) -> [UInt8] {
        var mac = [UInt8](repeating: 0, count: 64)
        CCHmac(algorithm.value, &secretKey, secretKey.count, &cipherText, cipherText.count, &mac)
        return mac
    }

算法定义如下：

enum HMACAlgorithm {
        case sha512

        var value: UInt32 {
            switch(self) {
            case .sha512:
                return UInt32(kCCHmacAlgSHA512)
            }
        }
    }

在这个例子中，我的密文是cipherText + IV。当您不使用AES-GCM时，似乎建议/建议使用HMAC IV + Cipher，但我无法向您提供有关原因的技术细节。

将数据或NSData转换为字节数组：

var byteArray = data.withUnsafeBytes { [UInt8](UnsafeBufferPointer(start: $0, count: data.count) }

使用数组的原因是数据的性能大幅增加，我不知道核心团队在做什么，但数据表现甚至比NSMutableData差。

如何在Swift 4中复制hash_hmac（'sha256'，$ key，$ secret_key）函数？

2 个答案:

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