text: /*******************************************************************************
  *   Ledger Blue - Bitcoin Wallet
  *   (c) 2016 Ledger
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
  *  You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  *  Unless required by applicable law or agreed to in writing, software
  *  distributed under the License is distributed on an "AS IS" BASIS,
  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  ********************************************************************************/
  
  #include "btchip_internal.h"
  #include "btchip_apdu_constants.h"
  
  #define MAX_LENGTH 248
  
  unsigned short btchip_apdu_get_random() {
      unsigned char length = G_io_apdu_buffer[ISO_OFFSET_LC];
      if (length == 0) {
          length = MAX_LENGTH;
      }
  
      if (length > MAX_LENGTH) {
          return BTCHIP_SW_INCORRECT_LENGTH;
      }
  
      cx_rng(G_io_apdu_buffer, length);
  
      btchip_context_D.outLength = length;
  
      return BTCHIP_SW_OK;
  }
  