Can Vehicles Talk to Each Other: V2V Makes Driving Safer

Can Vehicles Talk to Each Other: V2V Makes Driving Safer

In the pursuit of safer driving, vehicle-to-vehicle (V2V) communication is ready to begin saving lives. However, what’s to keep hackers from disrupting traffic and causing more accidents? V2V design protects car and driver with best practice security and largest public key infrastructure in history – driving technology advances that will benefit all Internet of Things (IoT) industries with high performance, cost effective security solutions.

By: Gregory Rudy
Green Hills Software, INTEGRITY Security Services

Long before the Infotainment system, preparing for our family road trips included “building the nest” — with pillows and blankets strewn across the suitcases for the kids to lie down. I still remember the day when riding in the back, or anywhere but the buckled seat, all came to an end.
It came to an end for good reason. Enactment of vehicle safety and seatbelt standards by the National Highway Traffic Safety Administration (NHTSA) reduced the risk of vehicle fatalities by 50% between 1982 and 2012. Despite significant improvement, the price tag for crashes still hit a staggering $871 billion in economic loss and societal harm in 2014.

A fundamental shift in thinking occurred during this time, from minimizing injury during an accident to preventing the accident altogether. Latest advanced driver assistance systems (ADAS) and vehicle-to-vehicle (V2V) communication initiatives use technology to extend necessary driver reaction time from milliseconds to several seconds. Fueling the investment, a NHTSA study concluded that V2V communication has the potential to prevent up to 75% of all roadway crashes. That’s over 24,000 lives saved annually.

The organization leading this deployment in the United States is the Crash Avoidance Metrics Partnership (CAMP), a consortium of automotive manufacturers and vendors in collaboration with US Department of Transportation (DOT) and NHTSA. The CAMP team is developing the specifications and prototype systems to make V2V a reality. Spearheading the deployment, General Motors (GM) announced that the 2017 Cadillac will be the first vehicle equipped with V2V technology.
With GM trailblazing and NHTSA expressing its intention to mandate V2V in all new vehicles, automotive technology providers are working hard to meet this demand. As a result of this effort, security is undergoing a major overhaul, which promises to benefit all devices across the Internet of Things (IoT).

What is V2V?
V2V-enabled vehicles utilize an on-board electronics (OBE) unit to transmit ten messages per second over a radio link. The data within these basic safety messages includes latitude, longitude, heading angle, speed, acceleration, and more. Messages from other vehicles are received and processed to predict the real-time movement of nearby vehicles up to 100 meters away. Based on this information, vehicles can detect collision events and notify the driver or even take independent action. Skidding on ice, pile-ups, sudden lane change crashes, and blind intersection accidents become intelligently avoidable. Figure 1.



Figure 1.  V2V communication extends ADAS to avoid accidents up to 100 meters


However, what’s to keep hackers from sending fake messages to disrupt traffic, ruining the many benefits of V2V? How are driver identities protected to keep them from being tracked and used for automated speeding tickets and target advertising? IEEE 1609.2 of the Wireless Access in Vehicular Environments (WAVE) specification addresses message security and privacy. The protocol uses the Elliptic Curve digital signatures to sign and verify safety messages, which are trusted based on certificates created by the Security Credential Management System (SCMS). The SCMS is a public key infrastructure being developed for the entire automotive industry to generate and revoke certificates. In order to protect privacy and keep vehicles from being tracked, the SCMS generates over 3,120 pseudonym certificates per OBE, which can be cycled through during operation at a rate of 20 per week. This complex security feature creates a virtual shell game of constantly changing certificates to protect driver identity.

The result is a robust end-to-end messaging solution, addressing both device security and public key infrastructure at the largest scale. As we transition to deployment, there are several technical challenges being overcome. While in the past, embedded developers had to choose between security and performance, V2V requires both, providing the impetus for transformative advances in security technology. These advances will benefit not only automotive, but secure networks of sensors and devices in all IoT industries.

Anyone stuck in Los Angeles freeway traffic at 5 o’clock on a Friday can imagine the number of messages a vehicle needs to process. While generating only ten digital signatures per second, the OBE must receive and verify many more. Assuming there are 20 cars in front and 20 behind (within the 100-meter range, across ten lanes of endless freeway traffic) the message protocol must authenticate upwards of 4,000 messages per second.

The problem is that software-based cryptographic libraries are capable of only 100-200 ECDSA verifies per second. Few commercial processors support elliptic core cryptography (ECC) acceleration, which has chip vendors seeking creative ways to offload the processing to any available specialized core. Using the digital signal processor, a 3-5x improvement is attainable, but still forces developers to pick and choose which messages to authenticate, opening doors for denial-of-service attacks.
ECC hardware acceleration can be used to meet this high performance. Products such as the cryptographic cores available with INTEGRITY Security Services’ V2X 1609.2 Toolkits, perform 2,500 ECC verifies per second and above. Traditionally, ECC hardware acceleration has been limited to high end ASICs and FPGA-based designs. This is changing thanks to V2V, where ECC in commercial processors will hopefully soon be as common as AES.

One of the reasons ECC was selected for V2V is the strength of the algorithm, relative to key size. ECC-224 is cryptographically equivalent to RSA 2048, but key and signature sizes are substantially smaller. The RSA-2048 key pair is around 1,200 bytes, plus another 750 bytes per certificate. Since privacy requires over 3,000 keys and certificates, RSA is not feasible because key storage alone is over 4MBs.
ECC-224 key sizes are vastly smaller. With an ECC-224 key size of only 28 bytes and certificates at 125 bytes, this is the optimal choice for V2V and other memory constrained embedded devices. The 1609.2 specification goes a step further and uses implicit ECQV (Elliptic Curve Qu-Vanstone) certificates to sign messages, saving up to 64 bytes per certificate. Privacy is therefore attainable through certificate shuffling because the total memory required is less than 500KBs.

The V2V SCMS is the massive public key infrastructure responsible for provisioning and revocation of vehicle certificates. The largest public key infrastructure (PKI) to-date is deployed by the US Department of Defense, issuing 10 million certificates annually. Including vehicles and infrastructure, the entire V2V system must support approximately 300 billion certificates per year.

SCMS design uses an intermediate certificate authority (CA) and other specialized components for each provisioning system. Vendors must decide whether they want to develop and operate their own or partner with a SCMS system provider. The overall PKI system enables message authentication to bridge multiple manufacturers across the entire industry. Figure 2.


Figure 2. INTEGRITY Security Services infrastructures include SCMS and PKI services to develop secure electronic control units for the most complex supply chains


The adoption of PKI into embedded devices benefits industries where multiple products and vendors must communicate securely without knowing the identities beforehand. Networking equipment, medical devices, and industrial controls rely on standards-based communication across multiple manufacturers. Strong security is limited without industry root CAs. Following the V2V example, further government support will promote the standardization of security infrastructures so secure communication may occur between vendors.

As the implementers of CAMP’s prototype SCMS and the first commercially deployed V2V provisioning system, INTEGRITY Security Services understands complex supply chains and secure sharing of digital trust assets worldwide. Certificate generation, key injection, and software digital signing are common infrastructure functions and available to meet the needs of today’s global product developers.

Security Platform
Accompanying 1609.2 discussions are additional requirements for the overall cryptographic platform and protection of OBE software and keys. Fundamental questions being asked are:
– “How are secrets being protected?”
– “Can the system detect if its software is tampered?”
– “How are remote endpoints, users, and messages authenticated?”
While 1609.2 addresses message authentication, the chain of trust is broken if either the ECC keys or software are compromised. Hacked OBEs are still usable as long as the certificates are not revoked. As a result, developers are also responding to requirements for secure boot and separation. While certificate revocation mitigates the impact of a compromise, secure boot, cryptographic hardware, and separation aim to prevent these incidents from occurring. Figure 3.


Figure 3. The OBE security platform protects messages, software, and keys for trustworthy operation


Beginning with an immutable root-of-trust, software is authenticated during startup to ensure it has not been modified prior to execution. The verification builds assurance that keys and critical data are not mishandled due to malware. However, all software contains defects and a bug anywhere in the software stack could cause vulnerability. Therefore, good separation design assumes software connected to external interfaces is already compromised and isolates keys and critical data appropriately into protected memory, partitions, or physical modules. This limits corruption to only one area without knocking out the whole system.

Riding On
They say it’s about the journey and not the destination. On this journey, the road to V2V reality is paved with technical advancements such as faster cryptographic processing, smaller key sizes, and the largest scale public key infrastructure in US history. Implementing these standards using best practice cryptographic design will secure messages and prevent cybersecurity attacks — much the same way V2V is preventing accidents. In this effort, Green Hills Software and INTEGRITY Security Services are building the end-to-end security and safety platforms to get there.
Perhaps one day, we’ll go back to building nests for our kids before the long car trips. The notable difference being that it will actually be safe. As the technology advances, maybe we’ll even get to sit in the back with them.

About the author
Gregory Rudy, Director of Business Development, joined Green Hills Software – INTEGRITY Security Services in 2014 through the acquisition of Valicore Technologies. Mr. Rudy has over 15 years of experience in the development of commercial and government technology. As systems architect at SafeNet Mykotronx, he lead the development of several cryptographic solutions, including the first Type 1 certified tactical handheld and tablet computers. Mr. Rudy holds a Bachelor of Science in Computer Engineering from Cal Poly, San Luis Obispo and Masters in Business from Johns Hopkins University.