我正在尝试使用Core Data和CommonCrypto加密数据。我正在尝试使用NSValueTransformer进行懒惰的加密和解密。
但是,当我现在尝试将加密数据保存到持久性存储协调器时,它会失败。每次我试图将数据保存到数据库时,它都会给我:
- [__ NSCFString bytes]:无法识别的选择器发送到实例
我确定它是某种数据库和NSManagedObject不匹配,但我无法弄明白。我觉得它可能相当简单,但我找不到解决方案。我的代码:
NSValueTransformer
class TryHardEncryption: NSValueTransformer {
override class func transformedValueClass() -> AnyClass {
return NSString.self
}
override class func allowsReverseTransformation() -> Bool {
return true
}
override func reverseTransformedValue(value: AnyObject?) -> AnyObject? {
if let message = value as? NSString {
let keyString = "12345678901234567890123456789012"
let keyData: NSData! = (keyString as NSString).dataUsingEncoding(NSUTF8StringEncoding) as NSData!
let keyBytes = UnsafeMutablePointer<Void>(keyData.bytes)
print("keyLength = \(keyData.length), keyData = \(keyData)")
let data: NSData! = (message as NSString).dataUsingEncoding(NSUTF8StringEncoding) as NSData!
let dataLength = size_t(data.length)
let dataBytes = UnsafeMutablePointer<Void>(data.bytes)
print("dataLength = \(dataLength), data = \(data)")
let cryptData = NSMutableData(length: Int(dataLength) + kCCBlockSizeAES128)
let cryptPointer = UnsafeMutablePointer<Void>(cryptData!.mutableBytes)
let cryptLength = size_t(cryptData!.length)
let keyLength = size_t(kCCKeySizeAES256)
let operation: CCOperation = UInt32(kCCDecrypt)
let algoritm: CCAlgorithm = UInt32(kCCAlgorithmAES128)
let options: CCOptions = UInt32(kCCOptionPKCS7Padding + kCCOptionECBMode)
var numBytesEncrypted :size_t = 0
let cryptStatus = CCCrypt(operation,
algoritm,
options,
keyBytes, keyLength,
nil,
dataBytes, dataLength,
cryptPointer, cryptLength,
&numBytesEncrypted)
if UInt32(cryptStatus) == UInt32(kCCSuccess) {
// let x: UInt = numBytesEncrypted
cryptData!.length = Int(numBytesEncrypted)
print("DecryptcryptLength = \(numBytesEncrypted), Decrypt = \(cryptData)")
// Not all data is a UTF-8 string so Base64 is used
let base64cryptString = cryptData!.base64EncodedStringWithOptions(.Encoding64CharacterLineLength)
print("base64DecryptString = \(base64cryptString)")
print( "utf8 actual string = \(NSString(data: cryptData!, encoding: NSUTF8StringEncoding))");
return base64cryptString
} else {
print("Error: \(cryptStatus)")
}
}
return nil
}
override func transformedValue(value: AnyObject?) -> AnyObject? {
if let message = value as? NSString {
let keyString = "12345678901234567890123456789012"
let keyData: NSData! = (keyString as NSString).dataUsingEncoding(NSUTF8StringEncoding) as NSData!
let keyBytes = UnsafePointer<UInt8>(keyData.bytes)
print("keyLength = \(keyData.length), keyData = \(keyData)")
let data: NSData! = message.dataUsingEncoding(NSUTF8StringEncoding) as NSData!
let dataLength = Int(data.length)
let dataBytes = UnsafePointer<UInt8>(data.bytes)
print("dataLength = \(dataLength), data = \(data)")
let cryptData = NSMutableData(length: Int(dataLength) + kCCBlockSizeAES128)!
let cryptPointer = UnsafeMutablePointer<UInt8>(cryptData.mutableBytes)
let cryptLength = size_t(cryptData.length)
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
let cryptStatus = CCCrypt(operation,
algoritm,
options,
keyBytes, keyLength,
nil,
dataBytes, dataLength,
cryptPointer, cryptLength,
&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)")
return NSString(string: base64cryptString) as NSObject
} else {
print("Error: \(cryptStatus)")
}
}
return nil
}
}
要让NSValueTransformer工作,我必须做的是:
let transformer: TryHardEncryption = TryHardEncryption()
NSValueTransformer.setValueTransformer(transformer, forName: "TryHardEncryption")
如果没有上述代码,则永远不会调用NSValueTransformer。
我已将数据库字段标记为Transformable类型并将其命名为:TryHardEncryption。你们知道这里有什么问题吗?
修改 它所涉及的财产是:
@NSManaged var establishmentDescription: String?
加密和解密函数在调试时都会返回一个字符串。
答案 0 :(得分:0)
我终于弄清楚了......我很困惑的是什么类型的对象必须是什么以及我的nsvaluetransformer必须返回什么。我没有在nsvaluetransformer中将值转换为正确的类型,因此我在代码中返回nil。然而它并没有以某种方式崩溃,我很容易想到这一点。其次,我将实体列更改回NSObject。返回transformValue方法中的NSData对象和reverseTransformedValue方法中的NSString。这实际上是我需要的才能让它发挥作用。非常感谢你的帮助。这确实是一个类型错误。
答案 1 :(得分:0)
为了帮助任何想要查看更正的代码示例的人,请将问题中的transformedValue()的返回行替换为:
return base64cryptString.dataUsingEncoding(NSUTF8StringEncoding)