Package com.google.crypto.tink.aead.internal

Class AesGcmSiv

  • All Implemented Interfaces:
    Aead
    public final class AesGcmSiv
extends java.lang.Object
implements Aead
    This primitive implements AES-GCM-SIV (as defined in RFC 8452) using JCE.

    This encryption mode is intended for authenticated encryption with associated data. A major security problem with AES-GCM is that reusing the same nonce twice leaks the authentication key. AES-GCM-SIV on the other hand has been designed to avoid this vulnerability.

    This encryption requires a JCE provider that supports the AES/GCM-SIV/NoPadding transformation such as Conscrypt. using JCE.

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      static interface  AesGcmSiv.ThrowingSupplier<T>
      A supplier that can throw a GeneralSecurityException.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      static Aead create​(AesGcmSivKey key, AesGcmSiv.ThrowingSupplier<javax.crypto.Cipher> cipherSupplier)
      Creates an Aead for AES GCM SIV.
      byte[] decrypt​(byte[] ciphertext, byte[] associatedData)
      On Android KitKat (API level 19) this method does not support non null or non empty associatedData.
      byte[] encrypt​(byte[] plaintext, byte[] associatedData)
      On Android KitKat (API level 19) this method does not support non null or non empty associatedData.
      static boolean isAesGcmSivCipher​(javax.crypto.Cipher cipher)
      Returns true if the cipher is an AES-GCM-SIV cipher.

      • Methods inherited from class java.lang.Object

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

    • Method Detail

      • isAesGcmSivCipher

        public static boolean isAesGcmSivCipher​(javax.crypto.Cipher cipher)
        Returns true if the cipher is an AES-GCM-SIV cipher.

        On Android API version 29 and older, Cipher.getInstance("AES/GCM-SIV/NoPadding") returns an AES-GCM cipher instead of an AES GCM SIV cipher. This function tests if we have a correct cipher.

      • create

        public static Aead create​(AesGcmSivKey key,
                          AesGcmSiv.ThrowingSupplier<javax.crypto.Cipher> cipherSupplier)
                   throws java.security.GeneralSecurityException
        Creates an Aead for AES GCM SIV.

        This function assumes that cipherSupplier provides correct implementations of AES GCM SIV. CipherSupplier may use isAesGcmSivCipher to ensure this.

        Throws:
        java.security.GeneralSecurityException

      • encrypt

        public byte[] encrypt​(byte[] plaintext,
                      byte[] associatedData)
               throws java.security.GeneralSecurityException
        On Android KitKat (API level 19) this method does not support non null or non empty associatedData. It might not work at all in older versions.
        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:
        java.security.GeneralSecurityException

      • decrypt

        public byte[] decrypt​(byte[] ciphertext,
                      byte[] associatedData)
               throws java.security.GeneralSecurityException
        On Android KitKat (API level 19) this method does not support non null or non empty associatedData. It might not work at all in older versions.
        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:
        java.security.GeneralSecurityException - if decryption fails. Decryption must fail if ciphertext is not correctly authenticated for the given associatedData.