com.google.crypto.tink.aead.internal

Class InsecureNonceXChaCha20

java.lang.Object

com.google.crypto.tink.aead.internal.InsecureNonceXChaCha20

public class InsecureNonceXChaCha20
extends Object

InsecureNonceXChaCha20 stream cipher based on https://download.libsodium.org/doc/advanced/xchacha20.html and https://tools.ietf.org/html/draft-arciszewski-xchacha-01.

This cipher is meant to be used to construct an AEAD with Poly1305. Specifically, it is only intended to be used for scenarios that require user-supplied nonces, which would be insecure if the user-supplied nonce ever repeats. Therefore, most users should prefer XChaCha20 instead, since it automatically supplies random nonce inputs.

Field Summary

Fields

Modifier and Type	Field and Description
static int	NONCE_SIZE_IN_BYTES

Constructor Summary

Constructors

Constructor and Description
InsecureNonceXChaCha20(byte[] key, int initialCounter) Constructs a new InsecureNonceXChaCha20 cipher with the supplied key.

Method Summary

Modifier and Type	Method and Description
byte[]	decrypt(byte[] nonce, byte[] ciphertext) Decrypts ciphertext using nonce.
byte[]	decrypt(byte[] nonce, ByteBuffer ciphertext) Decrypts ciphertext using nonce.
byte[]	encrypt(byte[] nonce, byte[] plaintext) Encrypts plaintext using nonce.
void	encrypt(ByteBuffer output, byte[] nonce, byte[] plaintext) Encrypts plaintext using nonce and writes result to output.

Methods inherited from class java.lang.Object

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

Field Detail

NONCE_SIZE_IN_BYTES

public static final int NONCE_SIZE_IN_BYTES

See Also:

Constant Field Values

Constructor Detail

InsecureNonceXChaCha20

public InsecureNonceXChaCha20(byte[] key,
                              int initialCounter)
                       throws InvalidKeyException

Constructs a new InsecureNonceXChaCha20 cipher with the supplied key.

Throws:

IllegalArgumentException - when key length is not ChaCha20Util.KEY_SIZE_IN_BYTES.

InvalidKeyException

Method Detail

encrypt

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

Encrypts plaintext using nonce.

Throws:

GeneralSecurityException

encrypt

public void encrypt(ByteBuffer output,
                    byte[] nonce,
                    byte[] plaintext)
             throws GeneralSecurityException

Encrypts plaintext using nonce and writes result to output.

Throws:

GeneralSecurityException

decrypt

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

Decrypts ciphertext using nonce.

Throws:

GeneralSecurityException

decrypt

public byte[] decrypt(byte[] nonce,
                      ByteBuffer ciphertext)
               throws GeneralSecurityException

Decrypts ciphertext using nonce.

Throws:

GeneralSecurityException