Java

HOTP Algorithm: HMAC-Based One-Time Password Algorithm

See more Encryption Examples

Demonstrates how to generate an HMAC one-time password (HOTP) as specified in RFC 4226.

Note: This example requires Chilkat v9.5.0.77 or greater.

Chilkat2 Java

import com.chilkatsoft.chilkat2.Crypt2;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example requires the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        Crypt2 crypt = new Crypt2();

        // Duplicate the following results from RFC 4226

        // Appendix D - HOTP Algorithm: Test Values
        //
        //   The following test data uses the ASCII string
        //   "12345678901234567890" for the secret:
        //
        //   Secret = 0x3132333435363738393031323334353637383930
        //
        //                     Truncated
        //   Count    Hexadecimal    Decimal        HOTP
        //   0        4c93cf18       1284755224     755224
        //   1        41397eea       1094287082     287082
        //   2         82fef30        137359152     359152
        //   3        66ef7655       1726969429     969429
        //   4        61c5938a       1640338314     338314
        //   5        33c083d4        868254676     254676
        //   6        7256c032       1918287922     287922
        //   7         4e5b397         82162583     162583
        //   8        2823443f        673399871     399871
        //   9        2679dc69        645520489     520489

        String secret = "12345678901234567890";
        for (int count = 0; count <= 9; count++) {
            String counterHex = crypt.encodeInt(count, 8, false, "hex");
            String hotp = crypt.hotp(secret, "ascii", counterHex, 6, -1, "sha1");
            System.out.println(count + "  HOTP = " + hotp);
        }

        // Output is:
        // 0  HOTP = 755224
        // 1  HOTP = 287082
        // 2  HOTP = 359152
        // 3  HOTP = 969429
        // 4  HOTP = 338314
        // 5  HOTP = 254676
        // 6  HOTP = 287922
        // 7  HOTP = 162583
        // 8  HOTP = 399871
        // 9  HOTP = 520489
    }
}