Method SHA256

Skay_Exp/src/tools/CryptLib.java:181–206

This function computes the SHA256 hash of input string @param text input text whose SHA256 hash has to be computed @param length length of the text to be returned @return returns SHA256 hash of input text @throws NoSuchAlgorithmException @throws UnsupportedEncodingException

(String text, int length)

     * @throws UnsupportedEncodingException
     */
    public static String SHA256 (String text, int length) throws NoSuchAlgorithmException, UnsupportedEncodingException {

        String resultStr;
        MessageDigest md = MessageDigest.getInstance("SHA-256");

        md.update(text.getBytes("UTF-8"));
        byte[] digest = md.digest();

        StringBuffer result = new StringBuffer();
        for (byte b : digest) {
            result.append(String.format("%02x", b)); //convert to hex
        }
        //return result.toString();

        if(length > result.toString().length())
        {
            resultStr = result.toString();
        }
        else
        {
            resultStr = result.toString().substring(0, length);
        }

        return resultStr;

    }

    /***
     * This function encrypts the plain text to cipher text using the key