First, the development of video surveillance technology
The first stage: analog monitoring, analog CCTV monitoring system CCTV that became popular in the 1970s. Front-end camera and background management all use analog technology. It can be said that it is of closed-circuit television type. It is very difficult to play back and query monitoring information and it is impossible to manage the background.
The second stage: digital surveillance, digital surveillance systems based on DVR/DVS that began to spread in the middle and late 90s of the last century achieved local digital compression storage. The front desk is still analog, but it digitizes the management and playback in the background.
The third stage: digitalize all the things that the front-end analog camera comes out of, and conduct a comprehensive digital management in the background.
The fourth stage: IP network monitoring. The digital video surveillance system based on the network that began to be popular in this century gradually realizes the integration of all-IP codec, IP network storage, and IP network.
Second, the city video surveillance security requirements and problems
Surveillance technology is now facing rapid changes. Analog video surveillance is shifting to IP network monitoring. Great changes also place higher demands on security. Combined with the recent monitoring of urban monitoring systems, the specific requirements for physical safety of systems construction and the problems of physical security are discussed.
Guaranteeing the physical security of various devices in the surveillance system is a prerequisite for ensuring the security of the entire system. Physical security is the stable operating state of the hardware of the networked system. It should protect the monitoring system equipment, facilities and media, and avoid or reduce environmental damage caused by earthquakes, floods, fires, and human damage caused by human misuse or vandalism. Physical security mainly includes: outdoor equipment safety, equipment room equipment safety, transmission line security, physical security of storage equipment, equipment safety of the entire network, and security of recording media.
There are more prominent common problems in the security at the current stage:
First, the risks of basic equipment include the security of servers and front-end node equipment in monitoring centers, the security of network equipment, and the security of transmission cables. Safe and reliable equipment is the basis for the safe operation of the entire alarm and monitoring system.
Second, the risk of information transmission on the network: including the protection of the confidentiality and integrity of the video information, video data information, user information during transmission, and the security of the node equipment on the transmission link. It also includes the security of front-end acquisition equipment and social monitoring resource access* monitoring private network.
Third, the risk of system operation: including access device identification and authentication, device operation failure, software viruses, malicious code, and device control priority scheduling. The risk control during system operation mainly depends on the video monitoring software platform. The software platform can complete a series of functions such as equipment management, fault monitoring, access control, user management, and authentication mechanisms to ensure the safe operation of the entire system.
Fourth, the risk of information access: including illegal user access, data loss, data falsification, etc. The security of system information mainly uses various encryption technologies, storage technologies, and backup solutions to achieve the security of system information.
In the work practice, the author discovered that there are hidden dangers in the physical security of some video surveillance systems. For example:
(1) The access control measures for the personnel of the monitoring center were weak, and there was no record or control over the entry and exit of personnel.
(II) There are problems with power supply security. The central computer room is not equipped with UPS backup equipment; the front-end equipment is not equipped with UPS backup equipment.
(3) In the lightning protection and grounding projects, the cross-sectional area of the bus bar, the cross-sectional area of the branch line, and the cross-sectional area of the ground wire of the equipment and workbench do not meet the requirements; the system signal input/output line is not equipped with a signal surge protector; the center room and the front end Equipment grounding failed.
(4) The cable laying technology of the front-end equipment is relatively rough. For example, equipment inside the equipment box is not securely installed or the camera does not have the necessary daily maintenance. Outdoor equipment is not equipped with measures such as protection against rain, dust and heat.
In short, physical security is the foundation of the foundation. No matter how the technology is updated and changed, physical security should be given sufficient attention. In addition, there are many aspects of security that need attention, such as access security, transmission network security, business security, and data security.
Third, the city should take measures for video surveillance security (A) monitoring center security measures
The monitoring centers at all levels shall be set within the protective areas. The entry and exit of personnel shall be recorded and controlled. The protective measures for the monitoring centers at all levels shall meet the design requirements and the requirements of 3.13 in GB50348-2004 to achieve internal security and fire prevention in the equipment room. Power distribution, air conditioning cooling, waterproof, moisture, anti-static and electromagnetic protection. The equipment should be properly placed and protected to reduce the risk of environmental threats and disasters and reduce the chances of unauthorized access. Consider implementing the following management measures:
1. Properly arrange the equipment to avoid unnecessary personnel from entering the work room.
2. The information processing and storage equipment handling critical data should be properly placed to minimize the risk of its lack of supervision; the redundancy of key equipment in the monitoring center should be able to guarantee the normal operation or rapid recovery of the system; and the backup of key equipment information of the system.
3. The installation of the monitoring center equipment should be stable, firm and reliable, with good ventilation and heat dissipation; the cable identification should be clear, accurate, wear-resistant, not easy to fall off, and the writing will not easily disappear.
4. Users should prohibit eating, drinking and smoking near information processing facilities.
5. The equipment room equipment should have a unified grounding management specification. It is recommended that the equipment room grounding should be divided into AC grounding, DC grounding, and work grounding. The grounding resistance should not be >4Ω. The lightning protection grounding should be set separately from other grounding, and the lightning protection grounding resistance should not be >1Ω.
6. The equipment room equipment should consider lightning protection measures. It is recommended that the building where the equipment room is located should be provided with lightning protection facilities, and lightning protection devices such as surge protectors and transient over-voltage protection devices should be added to the wiring system. All equipment in the system shall be installed within the scope of lightning protection; the cross-sectional area of the grounding bus, the cross-sectional area of the branch, and the cross-sectional area of the grounding wire of the equipment and the workbench shall meet the requirements in GA/670; the power supply line of the system shall be provided with power supply waves. Surge Protector (SPD), Signal Surge Protector (SPD) should be installed on the system signal input/output line.
(II) Safety Measures for Outdoor Equipment
Outdoor equipment needs to withstand harsh environments and various environmental factors must be considered, including temperature, humidity, altitude, corrosion protection, impact resistance, and vibration resistance. The installation of the front-end equipment should be firm and reliable to avoid various interference factors; the outdoor equipment should be provided with measures such as rainproof, dustproof and heat-dissipating; the construction quality of the front-end poles such as height and strength should meet the design requirements.
The installation of outdoor equipment should take into account the sealing of the equipment to prevent water leakage and water leakage affecting the electrical performance and normal use of the equipment; the outdoor equipment should also consider its anti-theft performance, and it is recommended to use the anti-theft installation box; the outdoor equipment power supply system should comply with equipment manufacturing. The requirements of the manufacturer and the need to install lightning protection devices on power lines and communication lines; the installation height of outdoor equipment should be reasonable to facilitate the maintenance of the equipment.
Designing a safe video surveillance system outdoor equipment should have the following characteristics:
1. The working environment temperature of outdoor equipment shall meet the following requirements: Facilities for outdoor work in cold regions: -40 to +35°C; Facilities for outdoor work in other regions: -10 to +55°C
2. The use of shielded electromagnetic radiation standard hood can effectively shield all kinds of electromagnetic interference, and the working performance is more stable and reliable.
3. Using a real-time embedded system, the system can run stably for a long time and supports 7X24 hour work mode.
4. The 24 DCP signal SPD is installed on each of the signal control lines.
5. The 10f/BNC signal SPD is installed on each of the IPC/video encoding server video input ports.
6. The lightning protection level meets the requirements of positive and negative 4KV, impulse current 3KA, and meets most of the requirements of induced lightning. In lightning high-risk areas, independent lightning protectors can be used for protection.
7. Anti-static is up to 8KV.
8. Passed mandatory national CCC certification requirements.
(III) Safety Measures for Equipment Room Equipment
Anti-electric strength: It should be able to withstand the electric strength test of 1.5kV, 50Hz AC voltage between the power plug or power supply lead-in terminal of the equipment and the exposed metal parts of the shell, and it should have no breakdown and arcing for 1min; leakage current: main equipment The leakage current to the protective ground during operation shall not exceed 5mA; Insulation resistance: The insulation resistance between the main equipment's power plug or power supply lead-in and the exposed metal parts of the equipment housing shall not be less than 5MΩ.
(D) Transmission Line Security Measures
Cables and communication lines for data transmission and auxiliary information services should be protected from interception or destruction. The following management measures should be considered:
1. Cables and communication lines connected to front-end node devices should be buried underground. In important nodes, redundant line protection is used;
2. When the power supply line and the communication line are separated (minimum interval 10cm) to prevent mutual interference;
3. For sensitive or critical systems, further management measures should also be considered, including:
1) The node should have an alternate communication path;
2) Optical fiber transmission should be used as far as possible, and the optical fiber should be buried underground;
3) Clear the unauthorized terminal equipment connected to the line.
(5) Physical security measures for storage devices
1. Long-term operation of storage devices requires high ambient temperature. It is required that the storage device itself can conveniently monitor the state of the environment, mainly the temperature index.
2. It is required that the storage device itself can monitor its own hardware running status in real time, such as the fan speed.
3. It is required that at least two fans be configured in front of the processor of the storage device. When the single fan of the processor is damaged, the system can meet the requirement of 30C ambient temperature for heat dissipation.
4. The design of important storage devices should be considered for redundancy, and for critical storage devices, backup solutions for off-site backups should also be considered.
(6) Safety Measures for Power Supply of the Whole Network Equipment
The device is protected from power interruptions or other power anomalies. And it is guaranteed to provide a suitable power supply that meets the requirements of the equipment manufacturer. The video surveillance system consists of an indoor control center and an outdoor front-end node. We propose different power security recommendations for these two subsystems.
1. Indoor power system security
The capacity of the power supply equipment of monitoring centers at all levels shall have a margin; the power supply system shall separate the power supply lines of the information system equipment from other power supply lines and shall be equipped with emergency lighting devices; line voltage regulation filter devices shall be configured to ensure the quality of the power supply Monitoring the standby power supply configured by the center, checking the power of related equipment, and the standby power capacity should be sufficient.
1) Power Supply Safety Recommendations
(1) The power distribution system output of the indoor control center should be 380V/220V, 50Hz, and the power supply quality of the equipment should reach class A (steady-state voltage offset range: ± 2%; steady-state frequency offset range: ± 0.2%; Voltage waveform distortion rate: 3-5%; duration of power interruption allowed: 0-4ms).
(2) Avoid power interference between devices. Network devices, servers, and computers should be isolated from high-power devices in the distribution system (such as large-screen display systems, air-conditioning systems, and lighting systems).
(3) The distribution box and cabinet should have short-circuit and over-current protection, and the emergency power-off button should be linked with the fire alarm.
(4) The indoor control center shall be equipped with a power supply, and the standby power supply shall ensure that the power supply for the alarm equipment and monitoring core equipment in the monitoring center is extended for not less than 8 hours.
(5) The system of the indoor control center should adopt two independent power sources and switch automatically at the end.
2) Uninterrupted power supply
The measures to be taken to achieve an uninterrupted power supply include:
(1) There are multiple ways of power supply to avoid a single point of power supply failure leading to system failure;
(2) Install uninterrupted power supply (UPS);
(3) Install a backup generator.
(4) For critical equipment or nodes, such as the central platform's various groups of servers and key front-end monitoring nodes, redundant power supply modules can be used (5) UPS selection should be based on the actual calculation of the load power, and leave a proper balance. Quantity (>10%), if necessary, consider UPS's n+1 backup scheme. The independent power supply of the UPS should at least ensure that the control center platform server works for more than two hours. At the same time, plans should be made to include measures to be taken when an uninterruptible power supply fails. UPS equipment should be inspected periodically to ensure that it is capable and tested according to the manufacturer's recommendations.
(6) In the event of long-term power outages and continued processing of information, standby generators need to be considered. After the generator is installed, it should be regularly tested according to the manufacturer's instructions. There should be sufficient fuel available to ensure that the generator can still operate during prolonged power outages.
2. Outdoor front-end node power supply security
1) The quality of the power supply should be the same as that of the indoor equipment.
2) The distribution box should have short-circuit and over-current protection measures.
3) The outdoor unit needs to provide waterproof measures for the power cable and power module.
(7) Electromagnetic compatibility safety measures
1. The anti-electromagnetic interference performance of the system equipment, especially the front-end acquisition equipment, shall meet the requirements of 9.1 of GA/T367-2001; the anti-jamming design of the transmission line shall comply with the provisions of 3.6.2 of GB50348-2004.
2. The electromagnetic radiation protection performance of the system shall meet the requirements of 9.2 of GA/T367-2001.
(8) Recording media safety measures
Appropriate specifications should be established to protect file archives, computer storage media (tapes, disks, cassettes, etc.), input/output data, and system files from damage, theft, and unauthorized access. Recording media library settings, registration of personnel entering and leaving the media repository; implementation of useful data, important data, high value-use data, high confidentiality data, and data recording media that play a key role in system operation and application Classification mark, registration and preservation; recording media library should be equipped with anti-theft and fire prevention functions; magnetic media should be used to prevent media from being magnetized; recording media should be stipulated with permission for approval, and have a high use value or a high degree of confidentiality in the system. The data should be protected by encryption and other methods; there should be strict management and approval procedures for important data that should be deleted and destroyed, and effective measures should be taken to prevent illegal copying. When not in use, the storage media should be safely and properly stored. The medium preventing the storage of sensitive information is leaked to outsiders due to its random placement. The following management measures should be considered:
Storage media that store sensitive information (including video surveillance video, audio recording, GIS data files, etc.) should use reliable methods of disposal, such as burning or crushing.
The collection and safe disposal control of paper, equipment, and storage media should be provided. The personnel involved in the disposal, preservation and management should have sufficient management measures and experience.
Records of storage media containing sensitive information (including video surveillance video, audio recording, GIS data files, etc.) should be recorded (for example, loaned, destroyed, etc.) for review.
Author's Unit * Department Third Institute
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