Android Question I need a small encryption

[tsteward]

I am looking for a way to do very simple encryption where the result is the same size or not much bigger than the original.
I like the idea of the result being hex that way it is simple for customers to relay.

So in my case I would encrypt a 4-10 digit code and give that to my customers. If and when they need that information they can tell me the code and I can decrypt it for them. This will mean that I don't need to keep this information, it is their responsibility.

Any suggestions?
I did look at Decrypter - De-/Encrypt String to base64 library but the result is too large.
Again doesn't need super security and I think hex result would be simplest to relay to customer and back again.

 

[Erel]

Base64 encoding has nothing to do with encryption.

Have you tried B4XEncryption? You can take the raw bytes and convert them to a string with Base64 encoding or ByteConverter.HexFromBytes (it will be less compact).

 

[KMatle]

Again doesn't need super security and I think hex result would be simplest to relay to customer and back again

So it's less an encryption and more like a serial code (like windows activation).

Sub CreateHexSerial
    Dim HexString As String = "01234567890ABCDEF"
    Dim Serial As String
      
    For I=0 To 9 '= length of 10
        Serial=Serial & HexString.CharAt(Rnd(0, HexString.Length))
        Serial=Serial & HexString.CharAt(Rnd(0, HexString.Length))
    Next

    Log(Serial)
   
End Sub

 

[tsteward]

I don't understand working with bytes etc.
I have tried B4XEncryption, the result is a little long and uses too many abnormal characters.

It doesn't have to be encryption as such it could be some form of encoding or maybe substitution.
It just needs to be easy to relay manually say over the phone.

Random serial is not what I need. I want to provide a key code for a vehicle or an immobiliser pin for my customers to keep but in a format that keeps them coming back to me or users of my app.

Typical key code W3234
Typical pin 1AE23E

 

[Erel]

KMatle code should work (it is better to use StringBuilder instead of String).