Swift 3 Compiler Error : 'bytes' is unavailable: use withUnsafeBytes instead - ios

Question

I have an encrypting method in Swift 2.2. How can I get bytes from data in Swift 3?
Here is my code:
func myEncrypt(encryptData:String) -> String? {
//security key must be 24charachters
let myKeyData : Data = "*******".data(using: String.Encoding.utf8)!
let myRawData : Data = encryptData.data(using: String.Encoding.utf8)!
let mykeydatamd5 = Data(bytes: myKeyData.bytes, count: 24)
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: Data = Data(bytes: buffer, count: num_bytes_encrypted)
free(buffer)
return myResult.base64EncodedString()
}else{
free(buffer)
return nil
}
}
The error occurs in myKeyData.bytes and myRawData.bytes.

Answer 1

As shown in the error message, you need to use withUnsafeBytes instead.
Generally, if you have some expression like this:
let result = someFunc(..., data.bytes, ...)
You need to rewrite it as:
let result = data.withUnsafeBytes {dataBytes in
someFunc(..., dataBytes, ...)
}
If you use multiple .bytes in a single expression, you may need to use nested withUnsafeBytes. In your case the related part of your code should be something like this:
let mykeydatamd5 = myKeyData.subdata(in: 0..<24) //Assuming myKeyData.count >= 24
let crypto_status: CCCryptorStatus = mykeydatamd5.withUnsafeBytes {mykeydataBytes in
myRawData.withUnsafeBytes {myRawDataBytes in
CCCrypt(operation, algoritm, options, mykeydataBytes, keyLength, nil, myRawDataBytes, myRawData.count, buffer, buffer_size, &num_bytes_encrypted)
}
}

Answer 2

Try this
func myEncrypt(encryptData:String) -> String? {
//security key must be 24charachters
var myKeyData = [UInt8]()
var myRawData = [UInt8]()
for char in "*******".utf8{
myKeyData += [char]
}
for char in encryptData.utf8{
myRawData += [char]
}
let mykeydatamd5 = Data(bytes: myKeyData, count: 24)
let Crypto_status: CCCryptorStatus = CCCrypt(operation, algoritm, options, mykeydatamd5.bytes , keyLength, nil, myRawData, myRawData.count, buffer, buffer_size, &num_bytes_encrypted)
if UInt32(Crypto_status) == UInt32(kCCSuccess){
let myResult: Data = Data(bytes: buffer, count: num_bytes_encrypted)
free(buffer)
return myResult.base64EncodedString()
}else{
free(buffer)
return nil
}
}
Hope it will help you