Converting objective-c code to swift

Question

I really need some help to convert the objective-c code to swift using CryptoSwift. I'm not sure how to use functions like: bzero, getCString, malloc in Swift.

+(NSData*)encryptData:(NSData*)data
{
    static NSString *key = @"BitCave012345678";
    char keyPtr[kCCKeySizeAES128+1];
    bzero(keyPtr, sizeof(keyPtr));

    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
    NSUInteger dataLength = [data length];
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);

    size_t numBytesEncrypted = 0;

    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionECBMode,
                                          keyPtr,kCCKeySizeAES128,NULL,[data bytes],dataLength,
                                          buffer, bufferSize, &numBytesEncrypted);

    if(cryptStatus == kCCSuccess)
    {
        return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
    }

    free(buffer);

    return nil;
}

Does anyone has an idea how to satisfy arguments requiring pointers? I was trying using UnsafeMutablePointers and I also tried the code below, but I know it is completely wrong:

var key: NSString = "BitCave012345678"
        var keyPtr: Array<Character> = Array<Character>(count: 17, repeatedValue: "0")
        bzero(&keyPtr, 17*sizeof(Character))
        key.getCString(&keyPtr, maxLength: 17*sizeof(Character), encoding: NSUTF8StringEncoding)

Answer 1

Swift 2.0

It is not necessary to use bzero, getCString, malloc, here is an example that does not:

Add Security.framework to the project
Add #import to the bridging header.

// operation is either 'kCCEncrypt' or 'kCCDecrypt'
func testCrypt(data data:NSData, keyData:NSData, operation:Int) -> NSData? {
    let keyBytes = UnsafePointer<UInt8>(keyData.bytes)

    let dataLength = Int(data.length)
    let dataBytes  = UnsafePointer<UInt8>(data.bytes)

    let cryptData: NSMutableData! = NSMutableData(length: Int(dataLength) + kCCBlockSizeAES128)
    let cryptPointer = UnsafeMutablePointer<UInt8>(cryptData.mutableBytes)
    let cryptLength  = size_t(cryptData.length)

    let keyLength              = size_t(kCCKeySizeAES128)
    let algoritm:  CCAlgorithm = UInt32(kCCAlgorithmAES128)
    let options:   CCOptions   = UInt32(kCCOptionECBMode + kCCOptionPKCS7Padding)

    var numBytesEncrypted :size_t = 0

    let cryptStatus = CCCrypt(CCOperation(operation),
        algoritm,
        options,
        keyBytes, keyLength,
        nil,
        dataBytes, dataLength,
        cryptPointer, cryptLength,
        &numBytesEncrypted)

    if UInt32(cryptStatus) == UInt32(kCCSuccess) {
        cryptData.length = Int(numBytesEncrypted)

    } else {
        print("Error: \(cryptStatus)")
    }

    return cryptData;
}

Example usage:

let keyData     = "12345678901234567890123456789012".dataUsingEncoding(NSUTF8StringEncoding)
let messageData = "Don´t try to read this text. Top Secret Stuff".dataUsingEncoding(NSUTF8StringEncoding)
let encrypted = testCrypt(data:messageData!, keyData:keyData!, operation:kCCEncrypt)

Here is version in Swift Arrays of UInt8 with no NSData objects:

func testCrypt(data data:[UInt8], keyData:[UInt8], operation:Int) -> [UInt8]? {
    let keyBytes = UnsafeMutablePointer<UInt8>(keyData)

    let dataLength = data.count
    let dataBytes  = UnsafeMutablePointer<UInt8>(data)

    var cryptData = [UInt8](count:data.count+kCCBlockSizeAES128, repeatedValue:0)
    let cryptPointer = UnsafeMutablePointer<UInt8>(cryptData)
    let cryptLength  = size_t(cryptData.count)

    let keyLength              = size_t(kCCKeySizeAES128)
    let algoritm:  CCAlgorithm = UInt32(kCCAlgorithmAES128)
    let options:   CCOptions   = UInt32(kCCOptionECBMode + kCCOptionPKCS7Padding)

    var numBytesEncrypted :size_t = 0

    let cryptStatus = CCCrypt(CCOperation(operation),
        algoritm,
        options,
        keyBytes, keyLength,
        nil,
        dataBytes, dataLength,
        cryptPointer, cryptLength,
        &numBytesEncrypted)

    if UInt32(cryptStatus) == UInt32(kCCSuccess) {
        cryptData.removeRange(numBytesEncrypted..<cryptData.count)

    } else {
        print("Error: \(cryptStatus)")
    }

    return cryptData;
}

Example usage:

let keyData     = Array("12345678901234567890123456789012".utf8)
let messageData = Array("Don´t try to read this text. Top Secret Stuff".utf8)
let encrypted   = testCrypt(data:messageData, keyData:keyData, operation:kCCEncrypt)