org.cryptacular.generator

Class TOTPGenerator

java.lang.Object

org.cryptacular.generator.AbstractOTPGenerator

org.cryptacular.generator.TOTPGenerator

public class TOTPGenerator
extends AbstractOTPGenerator

OTP generator component that implements the TOTP scheme described in RFC 6238.

Author:

Middleware Services

Constructor Summary

Constructors

Constructor and Description
TOTPGenerator()

Method Summary

Modifier and Type	Method and Description
protected long	currentTime()
int	generate(byte[] key) Generates the OTP given a per-user key.
protected org.bouncycastle.crypto.Digest	getDigest()
Spec<org.bouncycastle.crypto.Digest>	getDigestSpecification()
int	getStartTime()
int	getTimeStep()
protected void	setCurrentTime(long epochSeconds) Sets the current time (supports testing).
void	setDigestSpecification(Spec<org.bouncycastle.crypto.Digest> specification) Sets the digest algorithm used with the HMAC function.
void	setStartTime(int seconds) Sets the reference start time, T0.
void	setTimeStep(int seconds) Sets the time step, X.

Methods inherited from class org.cryptacular.generator.AbstractOTPGenerator

generateInternal, getNumberOfDigits, setNumberOfDigits

Methods inherited from class java.lang.Object

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

Constructor Detail

TOTPGenerator

public TOTPGenerator()

Method Detail

getDigestSpecification

public Spec<org.bouncycastle.crypto.Digest> getDigestSpecification()

Returns:

Digest algorithm used with the HMAC function.

setDigestSpecification

public void setDigestSpecification(Spec<org.bouncycastle.crypto.Digest> specification)

Sets the digest algorithm used with the HMAC function.

Parameters:

specification - SHA-1, SHA-256, or SHA-512 digest specification.

getStartTime

public int getStartTime()

Returns:

Reference start time.

setStartTime

public void setStartTime(int seconds)

Sets the reference start time, T0. Default 0, i.e. 1970-01-01T00:00:00.

Parameters:

seconds - Start time in seconds.

getTimeStep

public int getTimeStep()

Returns:

Time step in seconds.

setTimeStep

public void setTimeStep(int seconds)

Sets the time step, X.

Parameters:

seconds - Time step in seconds. Default is 30. This value determines the validity window of generated OTP values.

generate

public int generate(byte[] key)

Generates the OTP given a per-user key.

Parameters:

key - Per-user key.

Returns:

Integer OTP.

getDigest

protected org.bouncycastle.crypto.Digest getDigest()

Specified by:

getDigest in class AbstractOTPGenerator

Returns:

Digest algorithm used for HMAC operation.

setCurrentTime

protected void setCurrentTime(long epochSeconds)

Sets the current time (supports testing). This value is used if and only if it is a non-negative value; otherwise the current system time is used.

Parameters:

epochSeconds - Seconds since the start of the epoch, 1970-01-01T00:00:00.

currentTime

protected long currentTime()

Returns:

Current system time in seconds since the start of epoch, 1970-01-01T00:00:00.