Package com.google.crypto.tink.subtle

Class PrfHmacJce

java.lang.Object

com.google.crypto.tink.subtle.PrfHmacJce

All Implemented Interfaces:

Prf

@Immutable
public final class PrfHmacJce
extends java.lang.Object
implements Prf

Prf implementation using JCE.

Field Summary

Fields

Modifier and Type	Field	Description
static TinkFipsUtil.AlgorithmFipsCompatibility	FIPS

Constructor Summary

Constructors

Constructor	Description
PrfHmacJce(java.lang.String algorithm, java.security.Key key)

Method Summary

Modifier and Type	Method	Description
byte[]	compute(byte[] data, int outputLength)	Computes the PRF selected by the underlying key on input and returns the first outputLength bytes.
static Prf	create(HmacPrfKey key)	Given an HmacPrfKey, returns an instance of the Prf interface.
int	getMaxOutputLength()	Returns the maximum supported tag length.

Methods inherited from class java.lang.Object

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

Field Detail

FIPS

public static final TinkFipsUtil.AlgorithmFipsCompatibility FIPS

Constructor Detail

PrfHmacJce

public PrfHmacJce(java.lang.String algorithm,
                  java.security.Key key)
           throws java.security.GeneralSecurityException

Throws:

java.security.GeneralSecurityException

Method Detail

create

public static Prf create(HmacPrfKey key)
                  throws java.security.GeneralSecurityException

Given an HmacPrfKey, returns an instance of the Prf interface.

Throws:

java.security.GeneralSecurityException

compute

public byte[] compute(byte[] data,
                      int outputLength)
               throws java.security.GeneralSecurityException

Description copied from interface: Prf

Computes the PRF selected by the underlying key on input and returns the first outputLength bytes.

Specified by:

compute in interface Prf

Parameters:

data - the input to compute the PRF on.

outputLength - the desired length of the output in bytes. When choosing this parameter keep the birthday paradox in mind. If you have 2^n different inputs that your system has to handle set the output length to ceil(n/4 + 4) This corresponds to 2*n + 32 bits, meaning a collision will occur with a probability less than 1:2^32. When in doubt, request a security review.

Throws:

java.security.GeneralSecurityException - if the algorithm fails or if the output of algorithm is less than outputLength.

getMaxOutputLength

public int getMaxOutputLength()

Returns the maximum supported tag length.