Package io.getlime.security.powerauth.crypto.lib.util

Class HashBasedCounterUtils

java.lang.Object

io.getlime.security.powerauth.crypto.lib.util.HashBasedCounterUtils

public class HashBasedCounterUtils
extends Object

The HashBasedCounterUtils class provides additional functionality that allows secure transfer and verification of hash based counter over the network.

Constructor Summary

Constructors

Constructor	Description
HashBasedCounterUtils()

Method Summary

Modifier and Type	Method	Description
byte[]	calculateHashFromHashBasedCounter(byte[] ctrData, SecretKey transportKey)	Calculate hash from value representing the hash based counter.
boolean	verifyHashForHashBasedCounter(byte[] receivedCtrDataHash, byte[] expectedCtrData, SecretKey transportKey)	Verify whether client's value of hash based counter is equal to the value received from the server.

Methods inherited from class java.lang.Object

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

Constructor Details

HashBasedCounterUtils

public HashBasedCounterUtils()

Method Details

calculateHashFromHashBasedCounter

public byte[] calculateHashFromHashBasedCounter(byte[] ctrData,
 SecretKey transportKey)
                                         throws CryptoProviderException,
InvalidKeyException,
GenericCryptoException

Calculate hash from value representing the hash based counter. HMAC-SHA256 is currently used as a hashing function.

Parameters:

ctrData - Hash-based counter.

transportKey - Transport key.

Returns:

Hash calculated from provided hash-based counter.

Throws:

GenericCryptoException - In case that key derivation fails or you provided invalid ctrData.

CryptoProviderException - In case cryptography provider is incorrectly initialized.

InvalidKeyException - In case that transport key is not valid.

verifyHashForHashBasedCounter

public boolean verifyHashForHashBasedCounter(byte[] receivedCtrDataHash,
 byte[] expectedCtrData,
 SecretKey transportKey)
                                      throws CryptoProviderException,
InvalidKeyException,
GenericCryptoException

Verify whether client's value of hash based counter is equal to the value received from the server. The value received from the server is already hashed, so the function has to calculate hash from the client's counter and then compare both values.

Parameters:

receivedCtrDataHash - Value received from the server, containing hash, calculated from hash based counter.

expectedCtrData - Expected hash based counter.

transportKey - Transport key.

Returns:

true in case that received hash equals to hash calculated from counter data.

Throws:

InvalidKeyException - When invalid key is provided.

GenericCryptoException - In case key derivation fails.

CryptoProviderException - In case cryptography provider is incorrectly initialized.