code: public void processPacketAESCM(RawPacket pkt) {
  		long ssrc = pkt.getSSRC();
  		int seqNo = pkt.getSequenceNumber();
  		long index = ((long) this.roc << 16) | seqNo;
  
  		ivStore[0] = saltKey[0];
  		ivStore[1] = saltKey[1];
  		ivStore[2] = saltKey[2];
  		ivStore[3] = saltKey[3];
  
  		int i;
  		for (i = 4; i < 8; i++) {
  			ivStore[i] = (byte) ((0xFF & (ssrc >> ((7 - i) * 8))) ^ this.saltKey[i]);
  		}
  
  		for (i = 8; i < 14; i++) {
  			ivStore[i] = (byte) ((0xFF & (byte) (index >> ((13 - i) * 8))) ^ this.saltKey[i]);
  		}
  
  		ivStore[14] = ivStore[15] = 0;
  
  		final int payloadOffset = pkt.getHeaderLength();
  		final int payloadLength = pkt.getPayloadLength();
  
  		cipherCtr.process(cipher, pkt.getBuffer(), payloadOffset, payloadLength, ivStore);
  	}
docs: Perform Counter Mode AES encryption / decryption
  
  @param pkt
  the RTP packet to be encrypted / decrypted