Package com.bastiaanjansen.otp

Class TOTP

java.lang.Object

com.bastiaanjansen.otp.TOTP

All Implemented Interfaces:

TOTPGenerator, TOTPVerifier

public final class TOTP
extends Object
implements TOTPGenerator, TOTPVerifier

Generates time-based one-time passwords

Author:

Bastiaan Jansen

See Also:

OTP

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	TOTP.Builder

Field Summary

Fields

Modifier and Type	Field	Description
protected HMACAlgorithm	algorithm	Hashing algorithm used to generate code, defaults to SHA1
protected int	passwordLength	Number of digits for generated code in range 6...8, defaults to 6
protected byte[]	secret	Secret key used to generate the code, this should be a base32 string

Method Summary

Modifier and Type	Method	Description
String	at(long secondsPast1970)	Generate a time-based one-time password for a specific time based on seconds past 1970
String	at(Instant instant)	Generate a time-based one-time password for a Java instant
String	at(Date date)	Generate a time-based one-time password for a specific date
static TOTP	fromURI(URI uri)	Build a TOTPGenerator from an OTPAuth URI
protected String	generate(long counter)	Generate a code
HMACAlgorithm	getAlgorithm()
int	getPasswordLength()
Duration	getPeriod()
byte[]	getSecret()
URI	getURI(String issuer)	Create a OTPAuth URI for easy on-boarding with only an issuer
URI	getURI(String issuer, String account)	Create a OTPAuth URI for easy user on-boarding with an issuer and account name
protected URI	getURI(String type, String issuer, String account, Map<String,String> query)	Generate an OTPAuth URI
String	now()	Generate a time-based one-time password for current time interval instant
boolean	verify(String code)	Checks whether a code is valid for a specific counter
boolean	verify(String code, int delayWindow)	Checks whether a code is valid for a specific counter taking a delay window into account
boolean	verify(String code, long counter)	Checks whether a code is valid for a specific counter with a delay window of 0
boolean	verify(String code, long counter, int delayWindow)	Checks whether a code is valid for a specific counter taking a delay window into account
static TOTP	withDefaultValues(byte[] secret)	Create a TOTPGenerator with default values

Methods inherited from class java.lang.Object

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

Field Detail

passwordLength

protected final int passwordLength

Number of digits for generated code in range 6...8, defaults to 6

algorithm

protected final HMACAlgorithm algorithm

Hashing algorithm used to generate code, defaults to SHA1

secret

protected final byte[] secret

Secret key used to generate the code, this should be a base32 string

Method Detail

fromURI

public static TOTP fromURI(URI uri)
                    throws URISyntaxException

Build a TOTPGenerator from an OTPAuth URI

Parameters:

uri - OTPAuth URI

Returns:

TOTP

Throws:

URISyntaxException - when URI cannot be parsed

withDefaultValues

public static TOTP withDefaultValues(byte[] secret)

Create a TOTPGenerator with default values

Parameters:

secret - used to generate hash

Returns:

a TOTPGenerator with default values

now

public String now()
           throws IllegalStateException

Generate a time-based one-time password for current time interval instant

Specified by:

now in interface TOTPGenerator

Returns:

generated TOTP code

Throws:

IllegalStateException - when code could not be generated

at

public String at(Instant instant)
          throws IllegalStateException

Generate a time-based one-time password for a Java instant

Specified by:

at in interface TOTPGenerator

Parameters:

instant - an instant

Returns:

generated TOTP code

Throws:

IllegalStateException - when code could not be generated

at

public String at(Date date)
          throws IllegalStateException

Generate a time-based one-time password for a specific date

Specified by:

at in interface TOTPGenerator

Parameters:

date - specific date

Returns:

generated TOTP code

Throws:

IllegalStateException - when code could not be generated

at

public String at(long secondsPast1970)
          throws IllegalArgumentException

Generate a time-based one-time password for a specific time based on seconds past 1970

Specified by:

at in interface TOTPGenerator

Parameters:

secondsPast1970 - seconds past 1970

Returns:

generated TOTP code

Throws:

IllegalArgumentException - when code could not be generated

verify

public boolean verify(String code)

Checks whether a code is valid for a specific counter

Specified by:

verify in interface TOTPVerifier

Parameters:

code - an OTP code

Returns:

a boolean, true if code is valid, otherwise false

verify

public boolean verify(String code,
                      int delayWindow)

Checks whether a code is valid for a specific counter taking a delay window into account

Specified by:

verify in interface TOTPVerifier

Parameters:

code - an OTP code

delayWindow - window in which a code can still be deemed valid

Returns:

a boolean, true if code is valid, otherwise false

getPeriod

public Duration getPeriod()

getURI

public URI getURI(String issuer)
           throws URISyntaxException

Create a OTPAuth URI for easy on-boarding with only an issuer

Specified by:

getURI in interface TOTPGenerator

Parameters:

issuer - name

Returns:

generated OTPAuth URI

Throws:

URISyntaxException - when URI cannot be created

getURI

public URI getURI(String issuer,
                  String account)
           throws URISyntaxException

Create a OTPAuth URI for easy user on-boarding with an issuer and account name

Specified by:

getURI in interface TOTPGenerator

Parameters:

issuer - name

account - name

Returns:

generated OTPAuth URI

Throws:

URISyntaxException - when URI cannot be created

getPasswordLength

public int getPasswordLength()

getAlgorithm

public HMACAlgorithm getAlgorithm()

getSecret

public byte[] getSecret()

verify

public boolean verify(String code,
                      long counter)

Checks whether a code is valid for a specific counter with a delay window of 0

Parameters:

code - an OTP code

counter - how many times time interval has passed since 1970

Returns:

a boolean, true if code is valid, otherwise false

verify

public boolean verify(String code,
                      long counter,
                      int delayWindow)

Checks whether a code is valid for a specific counter taking a delay window into account

Parameters:

code - an OTP codee

counter - how many times time interval has passed since 1970

delayWindow - window in which a code can still be deemed valid

Returns:

a boolean, true if code is valid, otherwise false

generate

protected String generate(long counter)
                   throws IllegalStateException

Generate a code

Parameters:

counter - how many times time interval has passed since 1970

Returns:

generated OTP code

Throws:

IllegalStateException - when hashing algorithm throws an error

getURI

protected URI getURI(String type,
                     String issuer,
                     String account,
                     Map<String,String> query)
              throws URISyntaxException

Generate an OTPAuth URI

Parameters:

type - of OTPAuth URI: totp or hotp

issuer - name for URI

account - name for URI

query - items of URI

Returns:

created OTPAuth URI

Throws:

URISyntaxException - when URI cannot be created