swift aes 加密

1、需要引入 libSystem.dylib

2、添加NSData 类扩展，代码如下

extension NSData{
func AES128Crypt(operation:CCOperation,keyData:NSData)->NSData?{

let keyBytes        = keyData.bytes
let keyLength       = Int(kCCKeySizeAES256)

let dataLength      = self.length
let dataBytes       = self.bytes

let cryptLength     = Int(dataLength+kCCBlockSizeAES128)
var cryptPointer    = UnsafeMutablePointer<UInt8>.alloc(cryptLength)

let algoritm:  CCAlgorithm = CCAlgorithm(kCCAlgorithmAES128)
let option:   CCOptions    = CCOptions(kCCOptionECBMode + kCCOptionPKCS7Padding)

var numBytesEncrypted = UnsafeMutablePointer<Int>.alloc(1)
numBytesEncrypted.initialize(0)

var cryptStatus = CCCrypt(operation, algoritm, option, keyBytes, keyLength, nil, dataBytes, dataLength, cryptPointer, cryptLength, numBytesEncrypted)

if CCStatus(cryptStatus) == CCStatus(kCCSuccess) {
let len = Int(numBytesEncrypted.memory)
var data:NSData = NSData(bytesNoCopy: cryptPointer, length: len)

numBytesEncrypted.dealloc(1)
return data

} else {
numBytesEncrypted.dealloc(1)
cryptPointer.dealloc(cryptLength)

return nil
}
}

static func test(){
let keyString        = "12345678901234567890123456789012"
let keyData: NSData! = (keyString as NSString).dataUsingEncoding(NSUTF8StringEncoding) as NSData!

let message       = "Don´t try to read this text. Top Secret Stuff"
let data: NSData! = (message as NSString).dataUsingEncoding(NSUTF8StringEncoding) as NSData!

let result:NSData? = data.AES128Crypt(CCOperation(kCCEncrypt), keyData: keyData)
println("encrypt = \(result)")

let oldData = result?.AES128Crypt(CCOperation(kCCDecrypt), keyData: keyData)
println("decrypt = \(oldData)")
}
}

3、swift中指针的使用
c/c++中指针对应swift中的UnsafePointer & UnsafeMutablePointer

UnsafePointer 类型指向的内容不可变；UnsafeMutablePointer 类型指向的内容可以修改
swift中不可以对变量使用取地址操作