message: Update AES-SIV javadoc to clarify key size.
  GitOrigin-RevId:
diff: @@ -29,8 +29,9 @@ import javax.crypto.spec.SecretKeySpec;
  /**
  * AES-SIV, as described in <a href="https://tools.ietf.org/html/rfc5297">RFC 5297</a>.
  *
  - * <p>To meet the security requirements of {@link DeterministicAead}, this cipher can only be used
  - * with 256-bit keys.
  + * <p>Each AES-SIV key consists of two sub keys. To meet the security requirements of {@link
  + * DeterministicAead}, each sub key must be 256 bits. The total size of ASE-SIV keys is then 512
  + * bits.
  *
  * @since 1.1.0
  */
  