Package com.bastiaanjansen.otp

Class HOTPGenerator

java.lang.Object

com.bastiaanjansen.otp.OTPGenerator

com.bastiaanjansen.otp.HOTPGenerator

public class HOTPGenerator
extends OTPGenerator

Generates counter-based one-time passwords

Author:

Bastiaan Jansen

See Also:

• OTPGenerator

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	HOTPGenerator.Builder

Field Summary

Fields inherited from class com.bastiaanjansen.otp.OTPGenerator

algorithm, passwordLength, secret

Constructor Summary

Constructors

Constructor	Description
HOTPGenerator(int passwordLength, HMACAlgorithm algorithm, byte[] secret)	Constructs generator with custom password length

Method Summary

Modifier and Type	Method	Description
String	generate(long counter)	Generate a counter-based one-time password
URI	getURI(int counter, String issuer)	Create an OTPAuth URI for easy user on-boarding with only an issuer
URI	getURI(int counter, String issuer, String account)	Create an OTPAuth URI for easy user on-boarding with an issuer and account name

Methods inherited from class com.bastiaanjansen.otp.OTPGenerator

generateCode, getAlgorithm, getPasswordLength, getSecret, getURI, verify, verify

Methods inherited from class java.lang.Object

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

Constructor Details

HOTPGenerator

public HOTPGenerator(int passwordLength,
 HMACAlgorithm algorithm,
 byte[] secret)

Constructs generator with custom password length

Parameters:

passwordLength - number of digits for generated code in range 6...8

algorithm - HMAC hash algorithm used to hash data

secret - used to generate hash

Method Details

generate

public String generate(long counter)
                throws IllegalArgumentException

Generate a counter-based one-time password

Parameters:

counter - how many times time interval has passed since 1970

Returns:

generated HOTP code

Throws:

IllegalArgumentException - when code could not be generated

getURI

public URI getURI(int counter,
 String issuer)
           throws URISyntaxException

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

Parameters:

counter - of URI

issuer - name for URI

Returns:

OTPAuth URI

Throws:

URISyntaxException - when URI cannot be created

getURI

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

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

Parameters:

counter - of URI

issuer - name for URI

account - name for URI

Returns:

OTPAuth URI

Throws:

URISyntaxException - when URI cannot be created