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