Package com.amdelamar.jotp.type

Class TOTP

java.lang.Object

com.amdelamar.jotp.type.TOTP

All Implemented Interfaces:

OTPInterface

public class TOTP
extends java.lang.Object
implements OTPInterface

Time based OTP class implements OTPInterface

Since:

1.0.0

See Also:

https://tools.ietf.org/html/rfc6238

Constructor Summary

Constructors

Constructor	Description
TOTP()

Method Summary

Modifier and Type	Method	Description
java.lang.String	create(java.lang.String secret, java.lang.String base, int digits)	Create a one-time-password with the given key, base, and digits.
protected static java.lang.String	generateTotp(java.lang.String key, java.lang.String time, int digits, java.lang.String crypto)	Generates a TOTP value for the given set of parameters.
java.lang.String	getLabel()
protected static byte[]	hexStringToBytes(java.lang.String hex)	Converts a Hex based string to byte[]

Methods inherited from class java.lang.Object

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

Constructor Detail

TOTP

public TOTP()

Method Detail

getLabel

public java.lang.String getLabel()

Specified by:

getLabel in interface OTPInterface

create

public java.lang.String create(java.lang.String secret,
                               java.lang.String base,
                               int digits)
                        throws java.security.InvalidKeyException,
                               java.security.NoSuchAlgorithmException

Create a one-time-password with the given key, base, and digits.

Specified by:

create in interface OTPInterface

Parameters:

secret - The secret. Shhhhhh!

base - The offset. (TOTP base is time from UTC rounded to the half-second)

digits - The length of the code (Commonly '6')

Returns:

code

Throws:

java.security.NoSuchAlgorithmException - when HMAC is not available on this jvm

java.security.InvalidKeyException - when secret is invalid

See Also:

https://tools.ietf.org/html/rfc6238

hexStringToBytes

protected static byte[] hexStringToBytes(java.lang.String hex)

Converts a Hex based string to byte[]

Parameters:

hex - the HEX string

Returns:

byte array

generateTotp

protected static java.lang.String generateTotp(java.lang.String key,
                                               java.lang.String time,
                                               int digits,
                                               java.lang.String crypto)
                                        throws java.security.InvalidKeyException,
                                               java.security.NoSuchAlgorithmException

Generates a TOTP value for the given set of parameters.

Parameters:

key - the shared secret, HEX encoded

time - a value that reflects a time

digits - number of digits to return

crypto - the crypto function to use

Returns:

numeric String in base 10 that includes digits

Throws:

java.security.NoSuchAlgorithmException - if hmac sha1 is not available

java.security.InvalidKeyException - if given key is inappropriate for this mac