- private static SecureRandom getSecureRandom() {
- try {
- return SecureRandom.getInstance("SHA1PRNG");
- } catch (NoSuchAlgorithmException e) {
- throw new AssertionError(e);
+ public static String formatSafetyNumber(String digits) {
+ if (digits == null) {
+ return null;
+ }
+
+ final var partCount = 12;
+ var partSize = digits.length() / partCount;
+ var f = new StringBuilder(digits.length() + partCount);
+ for (var i = 0; i < partCount; i++) {
+ f.append(digits, i * partSize, (i * partSize) + partSize);
+ if (i != partCount - 1) {
+ f.append(" ");
+ }