com.google.crypto.tink.mac.internal

Class AesUtil

java.lang.Object

com.google.crypto.tink.mac.internal.AesUtil

public final class AesUtil
extends Object

A collection of byte-manipulation functions, and some more specific functions for AES-CMAC / AES-SIV.

Beware: some of the functions here are specific to the representation used for AES-CMAC and SIV, as described in their RFCs. These might not work if used in other contexts.

Field Summary

Fields

Modifier and Type	Field and Description
static int	BLOCK_SIZE

Method Summary

Modifier and Type	Method and Description
static byte[]	cmacPad(byte[] x) Pad by adding a 1 bit, then pad with 0 bits to the next block limit.
static byte[]	dbl(byte[] value) Multiplies value by x in the finite field GF(2^128) represented using the primitive polynomial x^128 + x^7 + x^2 + x + 1.

Methods inherited from class java.lang.Object

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

Field Detail

BLOCK_SIZE

public static final int BLOCK_SIZE

See Also:

Constant Field Values

Method Detail

dbl

public static byte[] dbl(byte[] value)

Multiplies value by x in the finite field GF(2^128) represented using the primitive polynomial x^128 + x^7 + x^2 + x + 1.

Parameters:

value - an arrays of 16 bytes representing an element of GF(2^128) using bigendian byte order.

cmacPad

public static byte[] cmacPad(byte[] x)

Pad by adding a 1 bit, then pad with 0 bits to the next block limit. This is the standard for both CMAC and AES-SIV. - https://tools.ietf.org/html/rfc4493#section-2.4 - https://tools.ietf.org/html/rfc5297#section-2.1

Parameters:

x - The array to pad (will be copied)

Returns:

The padded array.