在Swift中使用CCCrypt（CommonCrypt）的问题

Z时代
2024-01-10
分类：问答

我正在将工作中的Objective-C类别（NSData +

AESCrypt.m）移植到Swift，但发现使用指针存在问题。Swift中加密部分的代码可以正确编译，但是会生成运行时EXEC_BAD_ACCES错误。

到目前为止，我的代码是（我试图尽可能地剖析代码）：

let key = "123456789012345678901234567890120"
let keyLength = UInt(kCCKeySizeAES256 + 1)
let keyPointer = strdup(key)    // Convert key to <UnsafeMutablePointer<Int8>
let message = "Don´t try to read this text. Top Secret Stuff"
let data = (message as NSString).dataUsingEncoding(NSUTF8StringEncoding)
let dataBytes = data?.bytes
let length = data?.length
let dataLength = UInt(length!)
let dataPointer = UnsafePointer<UInt8>(dataBytes!)
let operation: CCOperation = UInt32(kCCEncrypt)
let algoritm: CCAlgorithm = UInt32(kCCAlgorithmAES128)
let options: CCOptions = UInt32(kCCOptionECBMode + kCCOptionPKCS7Padding)
let cryptBufferSize = UInt(dataLength + kCCBlockSizeAES128)
var cryptBuffer = [UInt8](count: Int(cryptBufferSize), repeatedValue: 0)
var cryptBufferPointer = UnsafeMutablePointer<UInt8>(cryptBuffer)
var numBytesEncrypted = UnsafeMutablePointer<UInt>()
var cryptStatus = CCCrypt(operation, algoritm, options, keyPointer, keyLength, nil, dataPointer, dataLength, cryptBufferPointer, cryptBufferSize, numBytesEncrypted)
if UInt32(cryptStatus) == UInt32(kCCSuccess) {
    let size = NSInteger(cryptBufferSize)
    let encryptedData = NSData(bytes: cryptBufferPointer, length: size)
    let encryptedString = NSString(data: encryptedData, encoding: NSUTF8StringEncoding)
    println("Encrypted String = \(encryptedString)") // EXEC_BAD_ACCESS error
} else {
    println("Error: \(cryptStatus)")
}

encryptionData对象显示以下信息：

<279c2d0f d3ce2200 0dc10cc1 9df46e76 cb26f423 7c9bde76 f9d8d0e2 632acef9 74fb0614 4717422b 684d1889 e3ce882c 00000000 00000000 00000000 0000>

但是，encryptedString

0x0000000000在调试器中显示，并且尝试对其进行调试println()会生成EXEC_BAD_ACCESS错误

知道缺少什么吗？

Rgds ....

回答：

雨燕2.0

这是一个示例，

如果这不完全是所需要的，则方法应该是一个很好的示例。

注意：密钥字符串将转换为数据

将Security.framework

添加#import <CommonCrypto/CommonCryptor.h>到项目中添加到桥接头。

let keyString        = "12345678901234567890123456789012"
let keyData: NSData! = (keyString as NSString).dataUsingEncoding(NSUTF8StringEncoding) as NSData!
print("keyLength   = \(keyData.length), keyData   = \(keyData)")
let message       = "Don´t try to read this text. Top Secret Stuff"
let data: NSData! = (message as NSString).dataUsingEncoding(NSUTF8StringEncoding) as NSData!
print("data length = \(data.length), data      = \(data)")
let cryptData    = NSMutableData(length: Int(data.length) + kCCBlockSizeAES128)!
let keyLength              = size_t(kCCKeySizeAES256)
let operation: CCOperation = UInt32(kCCEncrypt)
let algoritm:  CCAlgorithm = UInt32(kCCAlgorithmAES128)
let options:   CCOptions   = UInt32(kCCOptionECBMode + kCCOptionPKCS7Padding)
var numBytesEncrypted :size_t = 0
var cryptStatus = CCCrypt(operation,
    algoritm,
    options,
    keyData.bytes, keyLength,
    nil,
    data.bytes, data.length,
    cryptData.mutableBytes, cryptData.length,
    &numBytesEncrypted)
if UInt32(cryptStatus) == UInt32(kCCSuccess) {
    cryptData.length = Int(numBytesEncrypted)
    print("cryptLength = \(numBytesEncrypted), cryptData = \(cryptData)")
    // Not all data is a UTF-8 string so Base64 is used
    let base64cryptString = cryptData.base64EncodedStringWithOptions(.Encoding64CharacterLineLength)
    print("base64cryptString = \(base64cryptString)")
} else {
    print("Error: \(cryptStatus)")
}

输出：

keyLength   = 32, keyData   = <31323334 35363738 39303132 33343536 37383930 31323334 35363738 39303132>
dataLength  = 46, data      = <446f6ec2 b4742074 72792074 6f207265 61642074 68697320 74657874 2e20546f 70205365 63726574 20537475 6666>
cryptLength = 48, cryptData = <118a32dc c23f7caa 883abc3c 1c7f0770 e200016b 2737acfa 17bb96fb a02b02a7 c147603b 06acd863 94bb8ff2 6cb14515>
base64cryptString = EYoy3MI/fKqIOrw8HH8HcOIAAWsnN6z6F7uW+6ArAqfBR2A7BqzYY5S7j/JssUUV

迅捷3

iv前缀为加密数据

aesCBC128Encrypt将创建一个随机IV并以加密代码为前缀。

aesCBC128Decrypt在解密期间将使用带前缀的IV。

输入是数据，键是数据对象。如果需要，则使用诸如Base64之类的编码形式在调用方法中来回转换。

密钥的长度应精确为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，将引发错误。

默认设置为PKCS＃7填充。

此示例需要通用加密

。必须在项目中具有桥接头：

#import <CommonCrypto/CommonCrypto.h>

将添加Security.framework到项目中。

这是示例，而不是生产代码。

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;
}

用法示例：

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>