Question

我在java代码中有一个使用tripleDes和MD5的算法。有我的java代码：

 private String _encrypt(String message, String secretKey) throws Exception {

        MessageDigest md = MessageDigest.getInstance("MD5");
        byte[] digestOfPassword = md.digest(secretKey.getBytes("utf-8"));
        byte[] keyBytes = Arrays.copyOf(digestOfPassword, 16);

        SecretKey key = new SecretKeySpec(keyBytes, "DESede/ECB/PKCS7Padding");
        Cipher cipher = Cipher.getInstance("DESede/ECB/PKCS7Padding");
        cipher.init(Cipher.ENCRYPT_MODE, key);
        byte[] plainTextBytes = message.getBytes("utf-8");


        byte[] buf = cipher.doFinal(plainTextBytes);
        byte [] base64Bytes = Base64.encodeBase64(buf);
        String base64EncryptedString = new String(base64Bytes);

        return base64EncryptedString;
    }

我想在swift中使用tripleDes和MD5，我将这个java代码转换为swift但是swift中存在一个问题因为在java中使用16字节而swift使用24字节。如何解决java和swift编码之间的这种差异？有我的快捷代码：

    func myEncrypt(encryptData:String) -> String?{

            let myKeyData : NSData = ("Fanava@Wrapper!1395" as NSString).data(using: String.Encoding.utf8.rawValue)! as NSData
            let myRawData : NSData = encryptData.data(using: String.Encoding.utf8)! as NSData


   let mykeydatamd5 = Data(bytes: myKeyData.bytes, count: 24) // this key convert to 24 bytes but does not hash to md5 

  let mykeydatamd5 = Data(bytes: myKeyData.md5().bytes, count: 24) // this line converted key to md5(), 24byte, but it 


            let buffer_size : size_t = myRawData.length + kCCBlockSize3DES
            let buffer = UnsafeMutablePointer<NSData>.allocate(capacity: buffer_size)
            var num_bytes_encrypted : size_t = 0

            let operation: CCOperation = UInt32(kCCEncrypt)
            let algoritm:  CCAlgorithm = UInt32(kCCAlgorithm3DES)
            let options:   CCOptions   = UInt32(kCCOptionECBMode | kCCOptionPKCS7Padding)
            let keyLength        = size_t(kCCKeySize3DES)

            let Crypto_status: CCCryptorStatus =  CCCrypt(operation, algoritm, options, mykeydatamd5.bytes  , keyLength, nil, myRawData.bytes, myRawData.count, buffer, buffer_size, &num_bytes_encrypted)

            if UInt32(Crypto_status) == UInt32(kCCSuccess){

                let myResult: NSData = NSData(bytes: buffer, length: num_bytes_encrypted)

                free(buffer)

                return myResult.base64EncodedString(options: [])
            }else{
                free(buffer)

                return nil
            }
        }

Answer 1

以下是可以轻松修改TrippleDES的示例代码：

来自子集化的SO文档部分

对于CBC模式下的AES加密，使用随机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。

如果你必须为3DES修改这个功能。

对于PBKDF2加密**基于密码的密钥派生2（Swift 3 +）

基于密码的密钥派生既可用于从密码文本中导出加密密钥，也可用于保存密码以进行身份验证。

可以使用几种哈希算法，包括SHA1，SHA256，SHA512，这些算法由此示例代码提供。

rounds参数用于使计算变慢，以便攻击者必须在每次尝试上花费大量时间。典型的延迟值在100ms到500ms之间，如果有不可接受的性能，可以使用更短的值。

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。

参数：

password     password String  
salt         salt Data  
keyByteCount number of key bytes to generate
rounds       Iteration rounds

returns      Derived key


func pbkdf2SHA1(password: String, salt: Data, keyByteCount: Int, rounds: Int) -> Data? {
    return pbkdf2(hash:CCPBKDFAlgorithm(kCCPRFHmacAlgSHA1), password:password, salt:salt, keyByteCount:keyByteCount, rounds:rounds)
}

func pbkdf2SHA256(password: String, salt: Data, keyByteCount: Int, rounds: Int) -> Data? {
    return pbkdf2(hash:CCPBKDFAlgorithm(kCCPRFHmacAlgSHA256), password:password, salt:salt, keyByteCount:keyByteCount, rounds:rounds)
}

func pbkdf2SHA512(password: String, salt: Data, keyByteCount: Int, rounds: Int) -> Data? {
    return pbkdf2(hash:CCPBKDFAlgorithm(kCCPRFHmacAlgSHA512), password:password, salt:salt, keyByteCount:keyByteCount, rounds:rounds)
}

func pbkdf2(hash :CCPBKDFAlgorithm, password: String, salt: Data, keyByteCount: Int, rounds: Int) -> Data? {
    let passwordData = password.data(using:String.Encoding.utf8)!
    var derivedKeyData = Data(repeating:0, count:keyByteCount)

    let derivationStatus = derivedKeyData.withUnsafeMutableBytes {derivedKeyBytes in
        salt.withUnsafeBytes { saltBytes in

            CCKeyDerivationPBKDF(
                CCPBKDFAlgorithm(kCCPBKDF2),
                password, passwordData.count,
                saltBytes, salt.count,
                hash,
                UInt32(rounds),
                derivedKeyBytes, derivedKeyData.count)
        }
    }
    if (derivationStatus != 0) {
        print("Error: \(derivationStatus)")
        return nil;
    }

    return derivedKeyData
}

使用示例：

let password     = "password"
//let salt       = "saltData".data(using: String.Encoding.utf8)!
let salt         = Data(bytes: [0x73, 0x61, 0x6c, 0x74, 0x44, 0x61, 0x74, 0x61])
let keyByteCount = 16
let rounds       = 100000

let derivedKey = pbkdf2SHA1(password:password, salt:salt, keyByteCount:keyByteCount, rounds:rounds)
print("derivedKey (SHA1): \(derivedKey! as NSData)")

示例输出：

derivedKey (SHA1): <6b9d4fa3 0385d128 f6d196ee 3f1d6dbf>

在swift中使用TripleDes和MD5

1 个答案: