com.google.crypto.tink.prf.internal

Class PrfAesCmacConscrypt

java.lang.Object

com.google.crypto.tink.prf.internal.PrfAesCmacConscrypt

All Implemented Interfaces:

Prf

@Immutable
public final class PrfAesCmacConscrypt
extends Object
implements Prf

Prf implementation of AES-CMAC using Conscrypt.

AES-CMAC is defined in RFC 4493 and standardized by NIST in 800-38B.

This implementation here supports both 128-bit and 256-bit keys.

Method Summary

Modifier and Type	Method and 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(AesCmacPrfKey key) Returns a Prf primitive from an AesCmacPrfKey.

Methods inherited from class java.lang.Object

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

Method Detail

create

public static Prf create(AesCmacPrfKey key)
                  throws GeneralSecurityException

Returns a Prf primitive from an AesCmacPrfKey.

Throws:

GeneralSecurityException

compute

public byte[] compute(byte[] data,
                      int outputLength)
               throws 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:

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