simulcrypt 0.1.0

DVB Simulcrypt protocol messages encode/decode library, pure Python implementation.

Handling DVB Simulcrypt protocol messages

Pure Python library made with focus on compliance to DVB specifications.

Only these component-to-component interfaces covered:

• SCS ⇔ ECMG
• EMMG ⇔ MUX

Intended to help developing applications dealing with Simulcrypt packets. Could be useful for DigitalTV/DVB hardware simulation, monitoring, etc. Could be used to produce Prometheus metrics out of Simulcrypt traffic capture.

Quick start

$ python3
>>> from simulcrypt import SimulcryptMessage

How to make Simulcrypt packet object from bytes:

>>> message = SimulcryptMessage(bytes.fromhex('020001000e000e00020001000100044ae60000'))
>>> message
SimulcryptMessage(version=2, type=1, size=19, valid=True)

How to print the message content:

>>> message.data.hex()
'030001000e000e00020001000100044ae60000'

>>> message.log_line()
'CHANNEL_SETUP         ECM_channel_id=1, super_CAS_id=0x4ae60000'

>>> print(message.dump_json())
{"version":2,"message_type":1,"message_name":"CHANNEL_SETUP","message_length":19,
 "parameter_loop":[{"type":14,"name":"ECM_channel_id","length":2,"bytes":"0001"},{"type":1,"name":"super_CAS_id","length":4,"bytes":"4ae60000"}]}

>>> print(message.dump())
version: 2
message_type: 1
message_name: CHANNEL_SETUP
message_length: 19
parameter_type: 14
parameter_name: ECM_channel_id
parameter_length: 2
parameter_bytes: 0001
parameter_type: 1
parameter_name: super_CAS_id
parameter_length: 4
parameter_bytes: 4ae60000

Simulcrypt object properties and functions:

name	type	description
SimulcryptMessage.type	int	message type value
SimulcryptMessage.version	int	message version value (must be from 1 to 5)
SimulcryptMessage.length	int	message length in bytes
SimulcryptMessage.data	bytes	message raw bytes
SimulcryptMessage.is_simulcrypt	bool	True if message seems like Simulcrypt with correct version, type and length (no checks further)
SimulcryptMessage.is_valid	bool	True if message is valid Simulcrypt by checking all parameters presence, count and length
SimulcryptMessage.parameters	list	list of message parameters namedtuple("SimulcryptParameter", ["type", "name", "value"])
SimulcryptMessage.error_message	str	problem description if message isn't valid nor Simulcrypt
SimulcryptMessage.log_line()	function	produce one line representation of the message, useful for logging
SimulcryptMessage.dump()	function	output message content as plain text
SimulcryptMessage.dump_json()	function	output message content as JSON object

Advanced usage

How to create Simulcrypt message object using parameters and their values:

>>> from simulcrypt import SimulcryptSpecification as spec
>>> message = SimulcryptMessage(version=3, type=spec.ECMG_CHANNEL_SETUP, ECM_channel_id=1, super_CAS_id=0x4ae60000)
>>> message
SimulcryptMessage(version=3, type=1, size=19, valid=True)
>>> message.data
b'\x03\x00\x01\x00\x0e\x00\x0e\x00\x02\x00\x01\x00\x01\x00\x04J\xe6\x00\x00'

Parameter value could be of list type to make multiple instances. Here is example of multiple CP_CW_combination values in the message:

>>> message = SimulcryptMessage(verson=3, type=spec.CW_PROVISION, ECM_channel_id=1, ECM_stream_id=1, CP_number=0x7488,
CP_CW_combination=[bytes.fromhex('748845cbbe00000000be'), bytes.fromhex('748945cbc000000000c0')],
access_criteria=bytes.fromhex('900100060001006a0001'))
>>> message.data.hex()
'030201003c000e00020001000f000200010012000274880014000a748845cbbe00000000be0014000a748945cbc000000000c0000d000a900100060001006a0001'

All message types available:

name	hex/dec. type
SimulcryptSpecification.ECMG_CHANNEL_SETUP	0x0001 / 1
SimulcryptSpecification.ECMG_CHANNEL_TEST	0x0002 / 2
SimulcryptSpecification.ECMG_CHANNEL_STATUS	0x0003 / 3
SimulcryptSpecification.ECMG_CHANNEL_CLOSE	0x0004 / 4
SimulcryptSpecification.ECMG_CHANNEL_ERROR	0x0005 / 5
SimulcryptSpecification.EMMG_CHANNEL_SETUP	0x0011 / 17
SimulcryptSpecification.EMMG_CHANNEL_TEST	0x0012 / 18
SimulcryptSpecification.EMMG_CHANNEL_STATUS	0x0013 / 19
SimulcryptSpecification.EMMG_CHANNEL_CLOSE	0x0014 / 20
SimulcryptSpecification.EMMG_CHANNEL_ERROR	0x0015 / 21
SimulcryptSpecification.ECMG_STREAM_SETUP	0x0101 / 257
SimulcryptSpecification.ECMG_STREAM_TEST	0x0102 / 258
SimulcryptSpecification.ECMG_STREAM_STATUS	0x0103 / 259
SimulcryptSpecification.ECMG_STREAM_CLOSE_REQUEST	0x0104 / 260
SimulcryptSpecification.ECMG_STREAM_CLOSE_RESPONSE	0x0105 / 261
SimulcryptSpecification.ECMG_STREAM_ERROR	0x0106 / 262
SimulcryptSpecification.EMMG_STREAM_SETUP	0x0111 / 273
SimulcryptSpecification.EMMG_STREAM_TEST	0x0112 / 274
SimulcryptSpecification.EMMG_STREAM_STATUS	0x0113 / 275
SimulcryptSpecification.EMMG_STREAM_CLOSE_REQUEST	0x0114 / 276
SimulcryptSpecification.EMMG_STREAM_CLOSE_RESPONSE	0x0115 / 277
SimulcryptSpecification.EMMG_STREAM_ERROR	0x0116 / 278
SimulcryptSpecification.STREAM_BW_REQUEST	0x0117 / 279
SimulcryptSpecification.STREAM_BW_ALLOCATION	0x0118 / 280
SimulcryptSpecification.CW_PROVISION	0x0201 / 513
SimulcryptSpecification.ECM_RESPONSE	0x0202 / 514
SimulcryptSpecification.DATA_PROVISION	0x0211 / 529

All parameter names available:

context	hex/dec. type	length	name
EMMG ⇔ MUX	0x0001 / 1	4	client_id
EMMG ⇔ MUX	0x0002 / 2	1	section_TSpkt_flag
EMMG ⇔ MUX	0x0003 / 3	2	data_channel_id
EMMG ⇔ MUX	0x0004 / 4	3	data_stream_id
EMMG ⇔ MUX	0x0005 / 5	variable	datagram
EMMG ⇔ MUX	0x0006 / 6	2	bandwidth
EMMG ⇔ MUX	0x0007 / 7	1	data_type
EMMG ⇔ MUX	0x0008 / 8	2	data_id
EMMG ⇔ MUX	0x7000 / 28672	2	error_status
EMMG ⇔ MUX	0x7001 / 28673	variable	error_information
SCS ⇔ ECMG	0x0001 / 1	4	super_CAS_id
SCS ⇔ ECMG	0x0002 / 2	1	section_TSpkt_flag
SCS ⇔ ECMG	0x0003 / 3	2	delay_start
SCS ⇔ ECMG	0x0004 / 4	2	delay_stop
SCS ⇔ ECMG	0x0005 / 5	2	transition_delay_start
SCS ⇔ ECMG	0x0006 / 6	2	transition_delay_stop
SCS ⇔ ECMG	0x0007 / 7	2	ECM_rep_period
SCS ⇔ ECMG	0x0008 / 8	2	max_streams
SCS ⇔ ECMG	0x0009 / 9	2	min_CP_duration
SCS ⇔ ECMG	0x000A / 10	1	lead_CW
SCS ⇔ ECMG	0x000B / 11	1	CW_per_msg
SCS ⇔ ECMG	0x000C / 12	2	max_comp_time
SCS ⇔ ECMG	0x000D / 13	variable	access_criteria
SCS ⇔ ECMG	0x000E / 14	2	ECM_channel_id
SCS ⇔ ECMG	0x000F / 15	2	ECM_stream_id
SCS ⇔ ECMG	0x0010 / 16	2	nominal_CP_duration
SCS ⇔ ECMG	0x0011 / 17	1	access_criteria_transfer_mode
SCS ⇔ ECMG	0x0012 / 18	2	CP_number
SCS ⇔ ECMG	0x0013 / 19	2	CP_duration
SCS ⇔ ECMG	0x0014 / 20	variable	CP_CW_combination
SCS ⇔ ECMG	0x0015 / 21	variable	ECM_datagram
SCS ⇔ ECMG	0x0016 / 22	2	AC_delay_start
SCS ⇔ ECMG	0x0017 / 23	2	AC_delay_stop
SCS ⇔ ECMG	0x0018 / 24	variable	CW_encryption
SCS ⇔ ECMG	0x0019 / 25	2	ECM_id
SCS ⇔ ECMG	0x7000 / 28672	2	error_status
SCS ⇔ ECMG	0x7001 / 28673	variable	error_information

smdecode

Command-line tool to output Simulcrypt message content from hex stream:

$ smdecode -h
usage: smdecode [-h] [-j] HEXSTREAM

Decode hex stream of DVB Simulcrypt message.

positional arguments:
  HEXSTREAM   raw data hex stream (020201...)

options:
  -h, --help  show this help message and exit
  -j, --json  dump message(s) as JSON object

$ smdecode 030001000e000e00020001000100044ae60000
version: 3
message_type: 1
message_name: CHANNEL_SETUP
message_length: 19
parameter_type: 14
parameter_name: ECM_channel_id
parameter_length: 2
parameter_bytes: 0001
parameter_type: 1
parameter_name: super_CAS_id
parameter_length: 4
parameter_bytes: 4ae60000

$ smdecode -j 030001000e000e00020001000100044ae60000 | jq
{
  "version": 3,
  "message_type": 1,
  "message_name": "CHANNEL_SETUP",
  "message_length": 19,
  "parameter_loop": [
    {
      "type": 14,
      "name": "ECM_channel_id",
      "length": 2,
      "bytes": "0001"
    },
    {
      "type": 1,
      "name": "super_CAS_id",
      "length": 4,
      "bytes": "4ae60000"
    }
  ]
}

SCS/MUX simulators

This library includes sample of SCS and MUX component simulators:

$ scs -h
usage: scs [-h] [-s HOST] [-p PORT] [-c SEC] [-a AC] [-128] CAS_ID

DVB Simulcrypt V3 SCS component simulator.

positional arguments:
  CAS_ID                super_CAS_id value, 2 or 4 bytes

options:
  -h, --help            show this help message and exit
  -s HOST, --host HOST  ECMG server address or hostname, default is localhost
  -p PORT, --port PORT  TCP port number, default is 2000
  -c SEC, --cp SEC      crypto-period interval, default is min_CP_duration value received from ECMG
  -a AC, --ac AC        Scrambling Group access criteria hex string, default is none
  -128, --csa3          use 128-bit CW (DVB-CSA3/CISSA mode) instead of 64-bit default

$ mux -h
usage: mux [-h] [-p PORT] [-b BW] [-d] [-v NUM] [--channel_id ID] [--stream_id ID] [--data_id ID] CAS_ID

DVB Simulcrypt MUX component simulator.

positional arguments:
  CAS_ID                super_CAS_id or client_id, 2 or 4 bytes

options:
  -h, --help            show this help message and exit
  -p PORT, --port PORT  TCP port number, default is 2100
  -b BW                 EMM bandwith, default is 100kbps
  -d, --data            output DATA_PROVISION messages, default is not
  -v NUM                protocol version 1-5, default is accept from peer
  --channel_id ID       data_channel_id value, default is 0
  --stream_id ID        data_stream_id value, default is 0
  --data_id ID          data_id value, default is 0

Reference

• TR 102 035 v1.1.1 Implementation Guidelines of the DVB Simulcrypt Standard
• TS 101 197 v1.2.1 DVB SimulCrypt; Part 1: Head-end architecture and synchronization
• TS 103 197 v1.5.1 Head-end Implementation of SimulCrypt

Author & License

© 2020-2025 Victor Stepanov

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.