Question

我想使用DES在我的iOS应用程序中加密和解密字符串（是的，我知道DES不再安全，但应用程序接收并向使用它的BLE模块发送消息）。我成功地为Common Crypto创建了一个桥接头，我发现它用于加密并适用于DES和swift 3 Asynchronous encryption in Swift：

func testCrypt(data:NSData, keyData:NSData, ivData:NSData, operation:CCOperation) -> NSData? {

    let keyBytes = keyData.bytes.assumingMemoryBound(to: UInt8.self)
    print("keyLength   = \(keyData.length), keyData   = \(keyData)")

    let ivBytes = ivData.bytes.assumingMemoryBound(to: UInt8.self)
    print("ivLength    = \(ivData.length), ivData    = \(ivData)")

    let dataLength = Int(data.length)

    let dataBytes = data.bytes.assumingMemoryBound(to: UInt8.self)
    print("dataLength  = \(dataLength), data      = \(data)")

    let cryptData: NSMutableData! = NSMutableData(length: Int(dataLength) + kCCBlockSizeDES)

    let cryptPointer = cryptData.mutableBytes.assumingMemoryBound(to: UInt8.self)
    let cryptLength  = size_t(cryptData.length)

    let keyLength              = size_t(kCCKeySizeDES)
    let algoritm:  CCAlgorithm = UInt32(kCCAlgorithmDES)
    let options:   CCOptions   = UInt32(kCCOptionECBMode)

    var numBytesEncrypted :size_t = 0

    let cryptStatus = CCCrypt(operation,
                              algoritm,
                              options,
                              keyBytes, keyLength,
                              ivBytes,
                              dataBytes, dataLength,
                              cryptPointer, cryptLength,
                              &numBytesEncrypted)

    return cryptData;
}

函数调用和参数：

override func viewDidLoad() {
    super.viewDidLoad()

    let ivString = "Use a random iv!"
    let ivData = (ivString as NSString).data(using: String.Encoding.utf8.rawValue) as NSData!

    let key = Data.init(bytes: [0x23, 0x12, 0x4d, 0x89, 0x88, 0x34, 0xCf, 0x50])
    let keyData = NSData.init(data: key)

    let message = "Don´t try to read this text. Top Secret Stuff"
    let data = (message as NSString).data(using: String.Encoding.utf8.rawValue) as NSData!

    print("data: \(data)")
    if let encryptedData = testCrypt(data: data!, keyData:keyData, ivData: ivData!, operation:UInt32(kCCEncrypt)) {
        print("encryptedData: \(encryptedData)")
        if let decryptedData = testCrypt(data: encryptedData, keyData:keyData, ivData: ivData!, operation:UInt32(kCCDecrypt)) {
            let dec = Data.init(referencing: decryptedData)
            print("decryptedData: \(decryptedData))")
        }
    }
}

预期结果=＆lt; 446f6ec2 b4742074 72792074 6f207265 61642074 68697320 74657874 2e20546f 70205365 63726574 20537475 6666＆gt;

encryptedData：＆lt; 6081ada9 0487c0a5 35e542bd e9600861 4250a693 65573337 39df5525 66c40cd8 b358bf6a d9837f9c 00000000 00000000 00000000 0000＆gt;

decryptedData =＆lt; 446f6ec2 b4742074 72792074 6f207265 61642074 68697320 74657874 2e20546f 70205365 63726574 e0456e88 3f896b9b 00000000 00000000 00000000 0000＆gt;

为什么解密只返回部分正确的结果？

Answer 1

所以似乎没有可用的NoPadding选项，最后我刚从'cryptData'初始化中删除了'+ kCCBlockSizeDES'，并在加密它之前将'0'字符添加到我的字符串中以达到正确的大小（例如长度） 8）的倍数，然后在解密后我刚删除零以获得原始字符串。

使用Common Crypto在swift 3.1中进行DES / ECB / NoPadding

1 个答案: