来自日落文档部分的示例：

Question

我是从Swift 2更新为Swift 3的一款适用于客户端的应用，我正在处理commonCrypto（yikes！）。

我试图转换DES加密功能，但我不知道如何替换这段代码：

let cryptData: NSMutableData! = NSMutableData(length: Int(dataLength) + kCCBlockSizeDES)
let cryptPointer = UnsafeMutablePointer<UInt8>(cryptData.mutableBytes)

获取cryptPointer的正确方法是什么？到目前为止，我正在尝试：

var cryptData = Data(count: Int(dataLength) + kCCBlockSizeDES)
let cryptPointer = UnsafeMutablePointer<UInt8>.allocate(capacity: cryptData.count)
cryptData.copyBytes(to: cryptPointer, count: cryptData.count)

但我无法正确加密和解密。

请注意，我需要指针var，因为它是CCCrypt函数参数之一

Answer 1

（DES不安全，不应该用于新工作;它已被AES取代）

示例片段：

let cryptLength = size_t(data.count + kCCBlockSizeDES)
var cryptData = Data(repeating:0, count:cryptLength)
var numBytesEncrypted :size_t = 0

let keyLength             = size_t(kCCKeySizeDES)
let algoritm: CCAlgorithm = UInt32(kCCAlgorithmDES)
let options:  CCOptions   = UInt32(kCCOptionPKCS7Padding)

let cryptStatus = cryptData.withUnsafeMutableBytes {cryptBytes in
    data.withUnsafeBytes {dataBytes in
        ivData.withUnsafeBytes {ivBytes in
            keyData.withUnsafeBytes {keyBytes in
                CCCrypt(CCOperation(operation),
                        algoritm,
                        options,
                        keyBytes, keyLength,
                        ivBytes,
                        dataBytes, data.count,
                        cryptBytes, cryptLength,
                        &numBytesEncrypted)
            }
        }
    }
}

来自日落文档部分的示例：

CBC模式下的AES加密，随机IV（Swift 3 +）

iv以加密数据为前缀

aesCBC128Encrypt将创建一个随机IV，并以加密代码为前缀 aesCBC128Decrypt将在解密期间使用带前缀的IV。

输入是数据，键是数据对象。如果需要的编码形式（如Base64）在调用方法中转换为和/或来自

密钥长度应为128位（16字节），192位（24字节）或256位（32字节）。如果使用其他密钥大小，则会抛出错误。

PKCS#7 padding默认设置。

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。

这是示例，而非生产代码。

enum AESError: Error {
    case KeyError((String, Int))
    case IVError((String, Int))
    case CryptorError((String, Int))
}

// The iv is prefixed to the encrypted data
func aesCBCEncrypt(data:Data, keyData:Data) throws -> Data {
    let keyLength = keyData.count
    let validKeyLengths = [kCCKeySizeAES128, kCCKeySizeAES192, kCCKeySizeAES256]
    if (validKeyLengths.contains(keyLength) == false) {
        throw AESError.KeyError(("Invalid key length", keyLength))
    }

    let ivSize = kCCBlockSizeAES128;
    let cryptLength = size_t(ivSize + data.count + kCCBlockSizeAES128)
    var cryptData = Data(count:cryptLength)

    let status = cryptData.withUnsafeMutableBytes {ivBytes in
        SecRandomCopyBytes(kSecRandomDefault, kCCBlockSizeAES128, ivBytes)
    }
    if (status != 0) {
        throw AESError.IVError(("IV generation failed", Int(status)))
    }

    var numBytesEncrypted :size_t = 0
    let options   = CCOptions(kCCOptionPKCS7Padding)

    let cryptStatus = cryptData.withUnsafeMutableBytes {cryptBytes in
        data.withUnsafeBytes {dataBytes in
            keyData.withUnsafeBytes {keyBytes in
                CCCrypt(CCOperation(kCCEncrypt),
                        CCAlgorithm(kCCAlgorithmAES),
                        options,
                        keyBytes, keyLength,
                        cryptBytes,
                        dataBytes, data.count,
                        cryptBytes+kCCBlockSizeAES128, cryptLength,
                        &numBytesEncrypted)
            }
        }
    }

    if UInt32(cryptStatus) == UInt32(kCCSuccess) {
        cryptData.count = numBytesEncrypted + ivSize
    }
    else {
        throw AESError.CryptorError(("Encryption failed", Int(cryptStatus)))
    }

    return cryptData;
}

// The iv is prefixed to the encrypted data
func aesCBCDecrypt(data:Data, keyData:Data) throws -> Data? {
    let keyLength = keyData.count
    let validKeyLengths = [kCCKeySizeAES128, kCCKeySizeAES192, kCCKeySizeAES256]
    if (validKeyLengths.contains(keyLength) == false) {
        throw AESError.KeyError(("Invalid key length", keyLength))
    }

    let ivSize = kCCBlockSizeAES128;
    let clearLength = size_t(data.count - ivSize)
    var clearData = Data(count:clearLength)

    var numBytesDecrypted :size_t = 0
    let options   = CCOptions(kCCOptionPKCS7Padding)

    let cryptStatus = clearData.withUnsafeMutableBytes {cryptBytes in
        data.withUnsafeBytes {dataBytes in
            keyData.withUnsafeBytes {keyBytes in
                CCCrypt(CCOperation(kCCDecrypt),
                        CCAlgorithm(kCCAlgorithmAES128),
                        options,
                        keyBytes, keyLength,
                        dataBytes,
                        dataBytes+kCCBlockSizeAES128, clearLength,
                        cryptBytes, clearLength,
                        &numBytesDecrypted)
            }
        }
    }

    if UInt32(cryptStatus) == UInt32(kCCSuccess) {
        clearData.count = numBytesDecrypted
    }
    else {
        throw AESError.CryptorError(("Decryption failed", Int(cryptStatus)))
    }

    return clearData;
}

使用示例：

let clearData = "clearData0123456".data(using:String.Encoding.utf8)!
let keyData   = "keyData890123456".data(using:String.Encoding.utf8)!
print("clearData:   \(clearData as NSData)")
print("keyData:     \(keyData as NSData)")

var cryptData :Data?
do {
    cryptData = try aesCBCEncrypt(data:clearData, keyData:keyData)
    print("cryptData:   \(cryptData! as NSData)")
}
catch (let status) {
    print("Error aesCBCEncrypt: \(status)")
}

let decryptData :Data?
do {
    let decryptData = try aesCBCDecrypt(data:cryptData!, keyData:keyData)
    print("decryptData: \(decryptData! as NSData)")
}
catch (let status) {
    print("Error aesCBCDecrypt: \(status)")
}

示例输出：

clearData:   <636c6561 72446174 61303132 33343536>
keyData:     <6b657944 61746138 39303132 33343536>
cryptData:   <92c57393 f454d959 5a4d158f 6e1cd3e7 77986ee9 b2970f49 2bafcf1a 8ee9d51a bde49c31 d7780256 71837a61 60fa4be0>
decryptData: <636c6561 72446174 61303132 33343536>

注意：
CBC模式示例代码的一个典型问题是它将随机IV的创建和共享留给用户。此示例包括生成IV，加密数据前缀并在解密期间使用前缀IV。这使临时用户免于CBC mode所需的详细信息。

为了安全起见，加密数据也应该具有身份验证，这个示例代码不会提供这样的代码，因为它很小并且可以为其他平台提供更好的互操作性。

同样缺少密钥的密钥派生密钥，建议使用PBKDF2文本密码作为密钥材料使用。

对于强大的生产就绪的多平台加密代码，请参阅RNCryptor。

在Swift 3中创建UnsafeMutablePointer <uint8>

1 个答案:

来自日落文档部分的示例：