Null pointer exception when sample usage testing about format-preserving-encryption-java

[lijhua]

I also encountered this problem in the beginning, and solved it in the following way.
1, if the content to be encrypted contains only numbers, then construct NUM_CHARS like this
private static final char[] NUM_CHARS = new char[] {'1', '2', '3', '4', '5', '6', '7', '8', '9' , '0'}；
2, if the content to be encrypted contains numbers and uppercase letters, then construct NUM_CHARS
private static final char[] NUM_CHARS = new char[] {'1', '2', '3', '4', '5', '6', '7', '8','9','0','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};
3, other situations are changed with steps 1 and 2

then

BasicNums numAlphabet=new BasicNums();
TextToIntTransformer textToIntTransformer = new GenericTransformations(numAlphabet.availableCharacters());
IntToTextTransformer intToTextTransformer = new GenericTransformations(numAlphabet.availableCharacters());
String secretKey = "privateKeyText";
// with default values
FormatPreservingEncryption formatPreservingEncryption = FormatPreservingEncryptionBuilder
.ff1Implementation()
.withDomain(new GenericDomain(new BasicNums(), textToIntTransformer, intToTextTransformer))
.withDefaultPseudoRandomFunction(secretKey.getBytes())
.withDefaultLengthRange()
.build();

    String cipherText = formatPreservingEncryption.encrypt("1212321ASDSAD", "2088".getBytes());
    System.out.println(cipherText);
    String plainText = formatPreservingEncryption.decrypt(cipherText, "2088".getBytes());
    System.out.println(plainText);

output:
WU69RQ3AB5IRR
1212321ASDSAD

[laki88]

To solve that, I have created below class and added to classpath

package com.wso2telco.dep.user.masking;

import com.idealista.fpe.config.Alphabet;

public class BasicNums implements Alphabet {

    private static final char[] NUM_CHARS = new char[] {'1', '2', '3', '4', '5', '6', '7', '8', '9' , '0'};

    @Override
    public char[] availableCharacters() {
        return NUM_CHARS ;
    }

    @Override
    public Integer radix() {
        return NUM_CHARS.length;
    }
}

and used it as in below code

BasicNums numAlphabet = new BasicNums();
        TextToIntTransformer textToIntTransformer = new GenericTransformations(numAlphabet.availableCharacters());
        IntToTextTransformer intToTextTransformer = new GenericTransformations(numAlphabet.availableCharacters());

        // with default values
        FormatPreservingEncryption formatPreservingEncryption = FormatPreservingEncryptionBuilder
                .ff1Implementation()
                .withDomain(new GenericDomain(new BasicNums(), textToIntTransformer, intToTextTransformer))
                .withDefaultPseudoRandomFunction(secretKey.getBytes())
                .withDefaultLengthRange()
                .build();

[laki88]

The problem is it can't encrypt a number sequence. when I use letters in alphabet for the input stream I can encrypt and decrypt it without any issue.

[meghnad-globalids]

I am also facing the same issue, any updates on this?

[meghnad-globalids]

Will be possible for this encryption tool to encrypt character wise based on domain, as in my case the
string might be alphanumeric?