com.google.crypto.tink.subtle

Class AesEaxJce

java.lang.Object

com.google.crypto.tink.subtle.AesEaxJce

All Implemented Interfaces:

Aead

public final class AesEaxJce
extends Object
implements Aead

This class implements the EAX mode using AES.

EAX is an encryption mode proposed by Bellare, Rogaway and Wagner (http://web.cs.ucdavis.edu/~rogaway/papers/eax.pdf). The encryption mode is an alternative to CCM and has been proposed as a NIST standard: http://csrc.nist.gov/groups/ST/toolkit/BCM/documents/proposedmodes/eax/eax-spec.pdf

The parameter choices have been restricted to a small set of options:

• The tag size is always 16 bytes
• Nonces are chosen by the implementation at random. Their size is 12 or 16 bytes.

Plans: The current implementation is slow since it uses JCA and only assumes that the encryption modes "AES/ECB/NOPADDING" and "AES/CTR/NOPADDING" are implemented. Our plan is to implement a native version of EAX.

Since:

1.0.0

Field Summary

Fields

Modifier and Type	Field and Description
static TinkFipsUtil.AlgorithmFipsCompatibility	FIPS

Constructor Summary

Constructors

Constructor and Description
AesEaxJce(byte[] key, int ivSizeInBytes)

Method Summary

Modifier and Type	Method and Description
byte[]	decrypt(byte[] ciphertext, byte[] associatedData) Decrypts ciphertext with associatedData as associated authenticated data.
byte[]	encrypt(byte[] plaintext, byte[] associatedData) Encrypts plaintext with associatedData as associated authenticated data.

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

AesEaxJce

public AesEaxJce(byte[] key,
                 int ivSizeInBytes)
          throws GeneralSecurityException

Throws:

GeneralSecurityException

Method Detail

encrypt

public byte[] encrypt(byte[] plaintext,
                      byte[] associatedData)
               throws GeneralSecurityException

Description copied from interface: Aead

Encrypts plaintext with associatedData as associated authenticated data. The resulting ciphertext allows for checking authenticity and integrity of associated data (associatedData), but does not guarantee its secrecy.

Specified by:

encrypt in interface Aead

Parameters:

plaintext - the plaintext to be encrypted. It must be non-null, but can also be an empty (zero-length) byte array

associatedData - associated data to be authenticated, but not encrypted. Associated data is optional, so this parameter can be null. In this case the null value is equivalent to an empty (zero-length) byte array. For successful decryption the same associatedData must be provided along with the ciphertext.

Returns:

resulting ciphertext

Throws:

GeneralSecurityException

decrypt

public byte[] decrypt(byte[] ciphertext,
                      byte[] associatedData)
               throws GeneralSecurityException

Description copied from interface: Aead

Decrypts ciphertext with associatedData as associated authenticated data. The decryption verifies the authenticity and integrity of the associated data, but there are no guarantees wrt. secrecy of that data.

Specified by:

decrypt in interface Aead

Parameters:

ciphertext - the plaintext to be decrypted. It must be non-null.

associatedData - associated data to be authenticated. For successful decryption it must be the same as associatedData used during encryption. Can be null, which is equivalent to an empty (zero-length) byte array.

Returns:

resulting plaintext

Throws:

GeneralSecurityException