Saving Data on Android

initialization vector
 or an 
IV
.
An IV is a block of random bytes that are XOR’d with the leading block of the data. 
All subsequent blocks are dependent on the previous block, so using an IV uniquely 
encrypts the entire message.
Inside 
encrypt
, immediately below where you created the 
keySpec
, add the 
following code to create an IV:
// 9
 
val
 ivRandom = SecureRandom() 
// 10
 
val
 iv = ByteArray(
16
) 
// 11
 
ivRandom.nextBytes(iv) 
// 12
 
val
 ivSpec = IvParameterSpec(iv)
Here’s what’s happening:
9. Create a new 
SecureRandom
 object so that you’re not using a cached, seeded 
instance.
10. Create a byte array with a size of 
16
 to store the IV.
Saving Data on Android
Chapter 1: Using Files
raywenderlich.com
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11. Populate 
iv
 with random bytes.
12. Create the 
IvParameterSpec
 with the random 
iv
 so that you can use it when 
performing the encryption.
Now that you have created 
keySpec
 and 
ivSpec
 it’s time to use them to encrypt a 
note. In the next step, add the code to create a