Secure string pairs

StringHider.java

import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import javax.xml.bind.DatatypeConverter;

public class StringHider
{
    /**
     *  Generate pairs by doing:
     *  <p><code>
     *  SECRET=The secret to encode; SALT=$(pwgen 64); echo ${SALT}; echo -n ${SALT}${SECRET} | sha256sum | cut -d' ' -f1
     *  </code>
     */

    private static final String[][] myStringPairs =
    {
        { "etheihee1Pai4uuc4shoh3Uacheil9chu1uemieQuoB0IechahGeilo8meeth2Ze", "7005a45764cca26f1cce77830245f642b47ac55ea5dfd198cbad44f627ec9576" },
    };

    private static final MessageDigest md;
    static
    {
        try
        {
            md = MessageDigest.getInstance("SHA-256");
        } catch (NoSuchAlgorithmException e)
        {
            throw new RuntimeException("WOT?", e);
        }
    }

    public static boolean matches(String input)
    {
        byte[] inputBytes = input.getBytes(StandardCharsets.UTF_8);
        for (String[] pair : myStringPairs)
        {
            byte[] sha256 = DatatypeConverter.parseHexBinary(pair[1]);
            String sha256s = DatatypeConverter.printHexBinary(sha256);
            md.reset();
            md.update(pair[0].getBytes(StandardCharsets.US_ASCII));
            md.update(inputBytes);
            byte[] digest = md.digest();
            String string = DatatypeConverter.printHexBinary(digest);
            boolean result = MessageDigest.isEqual(sha256, digest);
            System.out.println("Digest " + string.length() + " " + string+ " " + result);
            System.out.println("SHA    " + sha256s.length() + " " + sha256s + " " + result);
            if (result) return true;
        }
        return false;
    }

    public static void main(String[] args)
    {
        System.out.println("Matches '" + args[0] + "' " + matches(args[0]));
    }
}