public static void decrypt(byte[] dest, int destOffset, InputStream in, int destSize,
    Context context, byte[] iv) throws IOException {
    Decryptor d = context.getCipher().getDecryptor();
    d.setKey(context.getKey());
    d.setIv(iv); // can be null
    decrypt(dest, destOffset, in, destSize, d);
  }
Decrypt a block of ciphertext from a stream given a context and IV
hbase-common/src/main/java/org/apache/hadoop/hbase/io/crypto/Encryption.java