IOS Swift3 DES,ECB,Padding Encryption - ios

Question

Below is my android java code, actually how to write this in IOS Swift3?
final SecretKey key = new SecretKeySpec(keyBytes, "DESede");
final Cipher cipher = Cipher.getInstance("DESede/ECB/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, key);
final byte[] cipherText = cipher.doFinal(plainTextBytes);

Answer 1

Find an AES or DES Common Crypto example here on SO and make changes as necessary to 3DES. Be sure the key is 24-bytes.
Change:
algorithm: CCAlgorithm3DES
mode: kCCModeECB
options: ccPKCS7Padding
If the key is 16-bytes it is two-key 3DES, duplicate and append the first 8-bytes to the end of the key to create a 24-byte key.
Note: DESede known as 3DES or Tripple-DES.
3DES is really not secure, especially 2-key 3DES. If at all possible update to AES-CBC with a random IV.
Here is untested Swift 3 (Should also work with Swift4)code, note the warning about the key length above:
func trippleDESCrypt(data:Data, keyData:Data, ivData:Data, operation:Int) -> Data? {
let cryptLength = size_t(data.count + kCCBlockSize3DES)
var cryptData = Data(repeating:0, count:cryptLength)
var numBytesEncrypted :size_t = 0
let keyLength = keyData.count
let algoritm: CCAlgorithm = UInt32(kCCAlgorithm3DES)
let options: CCOptions = UInt32(kCCOptionPKCS7Padding | kCCModeECB)
let cryptStatus = cryptData.withUnsafeMutableBytes {cryptBytes in
data.withUnsafeBytes {dataBytes in
ivData.withUnsafeBytes {ivBytes in
keyData.withUnsafeBytes {keyBytes in
CCCrypt(CCOperation(operation),
algoritm,
options,
keyBytes, keyLength,
ivBytes,
dataBytes, data.count,
cryptBytes, cryptLength,
&numBytesEncrypted)
}
}
}
}
if UInt32(cryptStatus) == UInt32(kCCSuccess) {
cryptData.count = numBytesEncrypted
}
else {
print("Error: \(cryptStatus)")
return nil
}
return cryptData
}
As usual you need to have a Bridging Header file that contains the import:
#import <CommonCrypto/CommonCrypto.h>
and you need to include the framework:
Security.framework.