org.jboss.security.otp

Class HOTP

java.lang.Object

org.jboss.security.otp.HOTP

public class HOTP
extends Object

Based on IETF RFC 4226 (http://tools.ietf.org/html/rfc4226) Code is derived from OATH HOTP algorithm

Since:

Sep 13, 2010

Author:

Anil.Saldhana@redhat.com

Constructor Summary

Constructors

Constructor and Description
HOTP()

Method Summary

Modifier and Type	Method and Description
static String	generateOTP(byte[] secret, long movingFactor, int codeDigits, boolean addChecksum, int truncationOffset) This method generates an OTP value for the given set of parameters.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

HOTP

public HOTP()

Method Detail

generateOTP

public static String generateOTP(byte[] secret,
                                 long movingFactor,
                                 int codeDigits,
                                 boolean addChecksum,
                                 int truncationOffset)
                          throws NoSuchAlgorithmException,
                                 InvalidKeyException

This method generates an OTP value for the given set of parameters.

Parameters:

secret - the shared secret

movingFactor - the counter, time, or other value that changes on a per use basis.

codeDigits - the number of digits in the OTP, not including the checksum, if any.

addChecksum - a flag that indicates if a checksum digit should be appended to the OTP.

truncationOffset - the offset into the MAC result to begin truncation. If this value is out of the range of 0 ... 15, then dynamic truncation will be used. Dynamic truncation is when the last 4 bits of the last byte of the MAC are used to determine the start offset.

Returns:

A numeric String in base 10 that includes codeDigits digits plus the optional checksum digit if requested.

Throws:

NoSuchAlgorithmException - if no provider makes either HmacSHA1 or HMAC-SHA-1 digest algorithms available.

InvalidKeyException - The secret provided was not a valid HMAC-SHA-1 key.