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The Advanced Encryption Standard (AES), also known as Rijndael (its original name), is a specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology (NIST) in 2001


The APDU (Application Protocol Data Unit) is the communication unit between a reader and a card. The setructure of an APDU is defined by the ISO 7816 standards. There are two categories of APDUs: command APDUs and response APDUs


Aftermarket Safety Device


Abstract Syntax Notation One (ASN.1) is a standard and notation that describes rules and structures for representing, encoding, transmitting, and decoding data in telecommunications and computer networking. The formal rules enable representation of objects that are independent of machine-specific encoding techniques.
Backend Management Commands


Basic Safety Message as defined in the SAE J2735 standard


In computer networking, a service set is a set consisting of all the devices associated with a consumer or enterprise IEEE 802.11 wireless local area network (WLAN). The service set can be local, independent, extended or mesh.

Service sets have an associated identifier, the Service Set Identifier (SSID), which consists of 32 octets that frequently contains a human readable identifier of the network.

The basic service set (BSS) provides the basic building-block of an 802.11 wireless LAN. In infrastructure mode, a single access point (AP) together with all associated stations (STAs) is called a BSS; not to be confused with the coverage of an access point, known as the basic service area (BSA). The access point acts as a master to control the stations within that BSS; the simplest BSS consists of one access point and one station. In OCB mode there is no access point and therefore all stations within reach is called a BSS.

The Blind Spot Warning and Lane Change Warning (BSW+LCW) application is intended to warn the driver of the vehicle during a lane change attempt if the blind-spot zone into which the vehicle intends to switch is, or will soon be, occupied by another vehicle traveling in the same direction. Moreover, the application provides advisory information that is intended to inform the driver that another vehicle in an adjacent lane is positioned in a blind-spot zone of the vehicle even if a lane change is not being attempted.


The CAR 2 CAR Communication Consortium (C2C-CC) is a nonprofit, industry-driven organization initiated by European vehicle manufacturers and supported by equipment suppliers, research organizations and other partners. The C2C-CC is dedicated to the objective of further increasing road traffic safety and efficiency by means of cooperative intelligent transport systems (ITS) with vehicle-to-vehicle communication (V2V) supported by vehicle-to-infrastructure communication (V2I).
C2XCar-to-X - the European version of V2X


In cryptography, a certificate authority or certification authority (CA) is an entity that issues digital certificates. A digital certificate certifies the ownership of a public key by the named subject of the certificate.


Crash Avoidance Metrics Partners LLC

A Controller Area Network (CAN bus) is a vehicle bus standard designed to allow microcontrollers and devices to communicate with each other in applications without a host computer. It is a message-based protocol, designed originally for multiplex electrical wiring within automobiles, but is also used in many other contexts.
In radio communication, a control channel (CCH) is a central channel that controls other constituent radios by handling data streams.


CCM mode (Counter with CBC-MAC) is a mode of operation for cryptographic block ciphers. It is an authenticated encryption algorithm designed to provide both authentication and confidentiality. CCM mode is only defined for block ciphers with a block length of 128 bits.

The Code of Federal Regulations (CFR) is the codification of the general and permanent rules and regulations (sometimes called administrative law) published in the Federal Register by the executive departments and agencies of the federal government of the United States
Certificate Management Entity


Communication Network Vehicle Road Global Extension (CONVERGE): Pioneering approaches to traffic management and vehicle safety issues are increasingly growing together. Still a holistic system architecture for flexible interaction between different service providers and communications network operators is missing in a decentralized, scalable structure. The aim of the project CONVERGE is to close this gap.

Certificate Provisioning Request


A Central Processing Unit (CPU) is the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions. The term has been used in the computer industry at least since the early 1960s.Traditionally, the term "CPU" refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.


Certificate Revocation Authorizing Certificate Authority


In the operation of some cryptosystems, usually public key infrastructures (PKIs), a Certificate Revocation List (CRL) is a list of certificates (or more specifically, a list of serial numbers for certificates) that have been revoked, and therefore, entities presenting those (revoked) certificates should no longer be trusted.


Certificate Revocation List Generator


Certificate Store
A CSR or Certificate Signing Request is a block of encrypted text that is generated by the device that will use the certificate. It contains information that will be included in your certificate such as PSID/SSP.


RTS/CTS (Request to Send / Clear to Send) is the optional mechanism used by the IEEE 802.11 wireless networking protocol to reduce frame collisions introduced by the hidden node problem. Originally the protocol fixed the exposed node problem as well, but modern RTS/CTS includes ACKs (acknowledgements) and does not solve the exposed node problem.


Device Configuration Manager.Attests to the ECA that an EE device is eligible to receive enrollment certificates, and provides all relevant configuration settings and certificates during bootstrapping.

The Distinguished Encoding Rules for ASN.1, abbreviated DER, are a subset of the Basic Encoding Rules (BER) specification, and give exactly one way to represent any ASN.1 value as an octet string. DER is intended for applications in which a unique octet string encoding is needed, as is the case when a digital signature is computed on an ASN.1 value.
A data frame (DF) is a digital data transmission unit in computer networking and telecommunication. A frame typically includes frame synchronization features consisting of a sequence of bits or symbols that indicate to the receiver the beginning and end of the payload data within the stream of symbols or bits it receives. If a receiver is connected to the system in the middle of a frame transmission, it ignores the data until it detects a new frame synchronization sequence.
The Do Not Pass Warning (DNPW) application is intended to warn the driver of the vehicle during a passing maneuver attempt when a slower moving vehicle, ahead and in the same lane, cannot be safely passed using a passing zone which is occupied by vehicles in the opposite direction of travel. In addition, the application provides advisory information that is intended to inform the driver of the vehicle that the passing zone is occupied when a vehicle is ahead and in the same lane even if a passing maneuver is not being attempted.


Domain Name Servers (DNS) are the Internet's equivalent of a phone book. They maintain a directory of domain names and translate them to Internet Protocol (IP) addresses. This is necessary because, although domain names are easy for people to remember, computers or machines, access websites based on IP addresses.


The Digital Signature Algorithm (DSA) is a Federal Information Processing Standard (FIPS) for digital signatures. It was proposed by the National Institute of Standards and Technology (NIST) in August 1991 for use in their Digital Signature Standard  and adopted as FIPS 186 in 1993. Four revisions to the initial specification have been released: FIPS 186-1 in 1996,FIPS 186-2 in 2000, FIPS 186-3 in 2009, and FIPS 186-4 in 2013.


Dedicated Short-Range Communications (DSRC) are one-way or two-way short-range to medium-range wireless communication channels specifically designed for automotive use and a corresponding set of protocols and standards.

Driver Vehicle Interface
Enrollment Certificate Authority. Issues enrollment certificates, which act as a passport for a device to authenticate against the RA, e.g., when requesting certificates. Different ECAs may issue enrollment certificates for different geographic regions, manufacturers, or device types.


In cryptography, a mode of operation is an algorithm that uses a block cipher to encrypt messages of arbitrary length in a way that provides confidentiality or authenticity. A block cipher by itself is only suitable for the secure cryptographic transformation (encryption or decryption) of one fixed-length group of bits called a block. A mode of operation describes how to repeatedly apply a cipher's single-block operation to securely transform amounts of data larger than a block. The simplest of the encryption modes is the Electronic Codebook (ECB) mode. The message is divided into blocks, and each block is encrypted separately.

Elliptic Curve Cryptography (ECC) is an approach to public-key cryptography based on the algebraic structure of elliptic curves over finite fields. ECC requires smaller keys compared to non-ECC cryptography (based on plain Galois fields) to provide equivalent security.


The Elliptic Curve Digital Signature Algorithm (ECDSA) offers a variant of the Digital Signature Algorithm (DSA) which uses elliptic curve cryptography.

Public-key cryptography is based on the intractability of certain mathematical problems. Early public-key systems are secure assuming that it is difficult to factor a large integer composed of two or more large prime factors. For elliptic-curve-based protocols, it is assumed that finding the discrete logarithm of a random elliptic curve element with respect to a publicly known base point is infeasible: this is the "elliptic curve discrete logarithm problem" or ECDLP. The security of ECC depends on the ability to compute a point multiplication and the inability to compute the multiplicand given the original and product points. The size of the elliptic curve determines the difficulty of the problem.


Elliptic Curve Integrated Encryption Scheme, or ECIES, is a hybrid encryption system proposed by Victor Shoup in 2001. ECIES has been standardized in ANSI X9.63, IEEE 1363a, ISO/IEC 18033-2, and SECG SEC-1. ECIES combines a Key Encapsulation Mechanism (KEM) with a Data Encapsulation Mechanism (DEM). The system independently derives a bulk encryption key and a MAC key from a common secret. Data is first encrypted under a symmetric cipher, and then the cipher text is MAC'd under an authentication scheme. Finally, the common secret is encrypted under the public part of a public/private key pair. The output of the encryption function is the tuple {K,C,T}, where K is the encrypted common secret, C is the ciphertext, and T is the authentication tag. There is some hand waiving around the "common secret" since its actually the result of applying a Key Agreement function, and it uses the static public key and an ephemeral key pair.


In cryptography, implicit certificates are a variant of public key certificate, such that a public key can be reconstructed from any implicit certificate, and is said then to be implicitly verified, in the sense that the only party who can know the associated private key is the party identified in the implicit certificate. This does not rule out the possibility that nobody knows the private key, but this possibility is not considered a major problem.

By comparison, traditional public-key certificates include a copy of the public key and the digital signature of the certificate authority. Upon verification of the digital signature, the public key is explicitly verified, in the sense that the party identified in the certificate knows the associated private key and is the only party who can know the private key. Unlike an implicit certificate, there is no possibility that nobody knows the private key. For the purposes of this document, such certificates will be called explicit certificates.

Elliptic Curve Qu-Vanstone (ECQV) are one kind of implicit certificates.

In automotive electronics, Electronic Control Unit (ECU) is a generic term for any embedded system that controls one or more of the electrical system or subsystems in a transport vehicle.
Enhanced Distributed Channel Access
The Emergency Electronic Brake Light (EEBL) application enables a vehicle to broadcast a self-generated emergency brake event to surrounding vehicles. Upon receiving the event information, the receiving vehicle determines the relevance of the event and, if appropriate, provides a warning to the driver in order to avoid a crash. This application is particularly useful when the driver's line of sight is obstructed by other vehicles or bad weather conditions (e.g., fog, heavy rain).

The European Geostationary Navigation Overlay Service (EGNOS) is a satellite based augmentation system (SBAS) developed by the European Space Agency, the European Commission and EUROCONTROL. It supplements the GPS, GLONASS and Galileo systems by reporting on the reliability and accuracy of the positioning data.

According to specifications, horizontal position accuracy should be better than seven metres. In practice, the horizontal position accuracy is at the metre level. The EGNOS system consists of four geostationary satellites and a network of ground stations.

Encryption Key

Electors represent the center of trust of the SCMS. Electors sign ballots that either endorse or revoke an RCA or another elector. The SCMS Manager distributes those ballots to all SCMS components, including devices, to establish trust relationships in RCAs and electors. An elector has a self-signed certificate, and all entities of the system will implicitly trust the initial set of electors. Therefore, all entities have to protect electors against unauthorized alteration, once they installed the initial set.


Europay-Mastercard-Visa Consortium
The European Telecommunications Standards Institute (ETSI) is an independent, not-for-profit, standardization organization in the telecommunications industry in Europe, headquartered in Sophia-Antipolis, France, with worldwide projection. 
The Federal Communications Commission (FCC) is an independent agency of the United States government, created by Congressional statute to regulate interstate communications by radio, television, wire, satellite, and cable in all 50 states, the District of Columbia and U.S. territories. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the media, public safety and homeland security, and modernizing itself.
The Forward Collision Warning (FCW) application is intended to warn the driver of the vehicle in case of an impending rear-end collision with another vehicle ahead in traffic in the same lane and direction of travel. The application uses data received from other vehicles to determine if a forward collision is imminent. FCW is intended to advise drivers to take specific action in order to avoid or mitigate rear-end vehicle collisions in the forward path of travel.


The Federal Highway Administration (FHWA) is a division of the United States Department of Transportation that specializes in highway transportation.

FIPS (Federal Information Processing Standards) are a set of standards that describe document processing, encryption algorithms and other information technology standards for use within non-military government agencies and by government contractors and vendors who work with the agencies.


In telecommunications and signal processing, frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. This contrasts with amplitude modulation, in which the amplitude of the carrier wave varies, while the frequency remains constant.


Federal Motor Vehicle Safety Standards (FMVSS) are U.S. federal regulations specifying design, construction, performance, and durability requirements for motor vehicles and regulated automobile safety-related components, systems, and design features.

A Fully Qualified Domain Name (FQDN) is the complete domain name for a specific computer, or host, on the Internet. The FQDN consists of two parts: the hostname and the domain name. For example, an FQDN for a hypothetical mail server might be
Global Certificate Chain File


Global Detection

Gigahertz. See Hertz
Global Misbehavior Detection is the process to identify potential misbehavior in the system, investigate suspicious activity, and if confirmed, to revoke certificates of misbehaving devices.

A satellite navigation system with global coverage may be termed a global navigation satellite system (GNSS). A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows small electronic receivers to determine their location (longitude, latitude, and altitude/elevation) to high precision (within a few metres) using time signals transmitted along a line of sight by radio from satellites. The system can be used for navigation or for tracking the position of something fitted with a receiver (satellite tracking). The signals also allow the electronic receiver to calculate the current local time to high precision, which allows time synchronisation. Satnav systems operate independently of any telephonic or internet reception, though these technologies can enhance the usefulness of the positioning information generated.

General Purpose
General Purpose Central Processing Unit
Global Policy File
Hybrid Coordination Function




A hardware security module (HSM) is a physical computing device that safeguards and manages digital keys for strong authentication and provides cryptoprocessing. These modules traditionally come in the form of a plug-in card or an external device that attaches directly to a computer or network server.


The Hypertext Transfer Protocol (HTTP) is an application protocol for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web.

Hypertext is structured text that uses logical links (hyperlinks) between nodes containing text. HTTP is the protocol to exchange or transfer hypertext.


HTTPS (also called HTTP over TLS, HTTP over SSL, and HTTP Secure) is a protocol for secure communication over a computer network which is widely used on the Internet. HTTPS consists of communication over Hypertext Transfer Protocol (HTTP) within a connection encrypted by Transport Layer Security (TLS) or its predecessor, Secure Sockets Layer (SSL). The main motivation for HTTPS is authentication of the visited website and protection of the privacy and integrity of the exchanged data.

Host Vehicle
The hertz (symbol Hz) is the unit of frequency in the International System of Units (SI) and is defined as one cycle per second. It is named for Heinrich Rudolf Hertz, the first person to provide conclusive proof of the existence of electromagnetic waves. Hertz are commonly expressed in SI multiples kilohertz (103 Hz, symbol kHz), megahertz (106 Hz, MHz), gigahertz (109 Hz, GHz), and terahertz (1012 Hz, THz).


Intermediate certificate authority (ICA): there are two types of certificate authorities (CAs), root CAs and intermediate CAs. The ICA serves as a secondary Certificate Authority to shield the RCA from traffic and attacks. The RCA issues the Intermediate CA certificate.


The Internet Corporation for Assigned Names and Numbers (ICANN /ˈkæn/ EYE-kan) is a nonprofit organization that is responsible for coordinating the maintenance and procedures of several databases related to the namespaces of the Internet - thereby ensuring the network's stable and secure operation. ICANN performs the actual technical maintenance work of the central Internet address pools and DNS Root registries pursuant to the Internet Assigned Numbers Authority (IANA) function contract.

The Institute of Electrical and Electronics Engineers (IEEE, pronounced "I triple E") is a professional association with its corporate office in New York City and its operations center in Piscataway, New Jersey. It was formed in 1963 from the amalgamation of the American Institute of Electrical Engineers and the Institute of Radio Engineers. Today, it is the world's largest association of technical professionals with more than 400,000 members in chapters around the world. Its objectives are the educational and technical advancement of electrical and electronic engineering, telecommunications, computer engineering and allied disciplines.
The Internet Engineering Task Force (IETF) develops and promotes voluntary Internet standards, in particular the standards that comprise the Internet protocol suite (TCP/IP). It is an open standards organization, with no formal membership or membership requirements. All participants and managers are volunteers, though their work is usually funded by their employers or sponsors.
Initial Linkage Seed
The Intersection Movement Assist (IMA) application warns the driver of a vehicle when it is not safe to enter an intersection due to high collision probability with other vehicles at stop sign controlled and uncontrolled intersections. This application can provide collision warning information to the vehicle operational systems which may perform actions to reduce the likelihood of crashes at the intersections.


The Internet Protocol (IP) is the principal communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet.

Internet Protocol Security (IPsec) is a protocol suite for securing Internet Protocol (IP) communications by authenticating and encrypting each IP packet of a communication session.

Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet, and was the first version deployed for production in the ARPANET in 1983. It still routes most Internet traffic today, despite the ongoing deployment of a successor protocol, IPv6. IPv4 is described in IETF publication RFC 791 (September 1981), replacing an earlier definition (RFC 760, January 1980).

IPv4 is a connectionless protocol for use on packet-switched networks. It operates on a best effort delivery model, in that it does not guarantee delivery, nor does it assure proper sequencing or avoidance of duplicate delivery. These aspects, including data integrity, are addressed by an upper layer transport protocol, such as the Transmission Control Protocol (TCP).


Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet. IPv6 was developed by the Internet Engineering Task Force (IETF) to deal with the long-anticipated problem of IPv4 address exhaustion. IPv6 is intended to replace IPv4.

Intelligent transportation systems (ITS) are advanced applications which, without embodying intelligence as such, aim to provide innovative services relating to different modes of transport and traffic management and enable various users to be better informed and make safer, more coordinated, and 'smarter' use of transport networks.


The ITS Joint Program Office (ITS JPO), within the Office of the Assistant Secretary for Research and Technology (OST-R), is charged with executing Subtitle C- Intelligent Transportation System Research of Public Law 109-59 Safe Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users, enacted August 10, 2005.


Kilohertz. See Hertz


Linkage Authority. Generates pre-linkage values, which are used to form linkage values that go in the certificates and support efficient revocation. There are two LAs in the SCMS, referred to as LA1 and LA2. The splitting prevents the operator of an LA from linking certificates belonging to a particular device.

Local Certificate Chain File


Linkage Chain Identifier

Local Certificate Management
The Blind Spot Warning and Lane Change Warning (BSW+LCW) application is intended to warn the driver of the vehicle during a lane change attempt if the blind-spot zone into which the vehicle intends to switch is, or will soon be, occupied by another vehicle traveling in the same direction. Moreover, the application provides advisory information that is intended to inform the driver that another vehicle in an adjacent lane is positioned in a blind-spot zone of the vehicle even if a lane change is not being attempted.
Local Misbehavior Detection
Location Obscurer Proxy. Hides the location of the requesting device by changing source addresses, and thus, prevents linking of network addresses to locations.
Local Policy File


Linkage Seed

Left Turn Assist (LTA) is an application intended to warn the driver when there is strong probability they will collide with an oncoming vehicle when making a left turn. This is especially critical when the driver’s line-of-sight is blocked by a vehicle also making a left turn from the opposite direction.


Linkage Value


Misbehavior Authority. Processes misbehavior reports to identify potential misbehavior or malfunctioning by devices, and revokes and adds them to the CRL, if necessary. It also initiates the process of linking a certificate identifier to the corresponding enrollment certificates and adding them to the RA's internal blacklist. The MA contains two subcomponents: Global Misbehavior Detection, which determines which devices are misbehaving; and CRL Generator, which generates, digitally signs and releases the CRL to the public.


The Media Access Control (MAC) Layer is one of two sublayers that make up the Data Link Layer of the Open System Interconnection (OSI) model. The MAC layer is responsible for moving data packets to and from one Network Interface Card to another across a shared channel.


In cryptography, a Message Authentication Code (MAC) is a short piece of information used to authenticate a message and to provide integrity and authenticity assurances on the message.


Misbehavior Report
Model Deployment
Megahertz. See Hertz.
A management information base (MIB) is a database used for managing the entities in a communication network. Most often associated with the Simple Network Management Protocol (SNMP), the term is also used more generically in contexts such as in OSI/ISO Network management model. While intended to refer to the complete collection of management information available on an entity, it is often used to refer to a particular subset, more correctly referred to as MIB-module.
MLME stands for Media Access Control (MAC) Sublayer Management Entity. MLME is the management entity where the Physical layer (PHY) MAC state machines reside.
Minimum Performance Requirements
Network Address Translation (NAT) is a method of remapping one IP address space into another by modifying network address information in Internet Protocol (IP) datagram packet headers while they are in transit across a traffic routing device.


The National Highway Traffic Safety Administration (NHTSA) is an agency of the Executive Branch of the U.S. government, part of the Department of Transportation. It describes its mission as "Save lives, prevent injuries, reduce vehicle-related crashes."

As part of its activities, NHTSA is charged with writing and enforcing Federal Motor Vehicle Safety Standards as well as regulations for motor vehicle theft resistance and fuel economy, the latter under the rubric of the Corporate Average Fuel Economy (CAFE) system. NHTSA also licenses vehicle manufacturers and importers, allows or blocks the import of vehicles and safety-regulated vehicle parts, administers the vehicle identification number (VIN) system, develops the anthropomorphic dummies used in safety testing, as well as the test protocols themselves, and provides vehicle insurance cost information. The agency has asserted preemptive regulatory authority over greenhouse gas emissions, but this has been disputed by such state regulatory agencies as the California Air Resources Board.


The National Institute of Standards and Technology (NIST) is a measurement standards laboratory, and a non-regulatory agency of the United States Department of Commerce. Its mission is to promote innovation and industrial competitiveness.

NIST's activities are organized into laboratory programs that include Nanoscale Science and Technology, Engineering, Information Technology, Neutron Research, Material Measurement, and Physical Measurement.

The National Marine Electronics Association (NMEA) is a US-based marine electronics trade organization setting standards of communication between marine electronics.
In cryptography, a Nonce is an arbitrary number that may only be used once. It is similar in spirit to a nonce word, hence the name. It is often a random or pseudo-random number issued in an authentication protocol to ensure that old communications cannot be reused in replay attacks. They can also be useful as initialization vectors and in cryptographic hash function.

Network Time Protocol (NTP) is a networking protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks. In operation since before 1985, NTP is one of the oldest Internet protocols in current use.

NTP is intended to synchronize all participating computers to within a few milliseconds of Coordinated Universal Time (UTC). It uses a modified version of Marzullo's algorithm to select accurate time servers and is designed to mitigate the effects of variable network latency. NTP can usually maintain time to within tens of milliseconds over the public Internet, and can achieve better than one millisecond accuracy in local area networks under ideal conditions. Asymmetric routes and network congestion can cause errors of 100 ms or more.


On-board Equipment

Outside the Context of a BSS (OCB) is a Wireless LAN mode that allows operation and data dissemination without association, avoiding signaling overhead prior to the actual data exchange. This is required to support the high dynamics of vehicular networks that can lead to extremely short contact times and thus, communication opportunities.
Original Equipment Manufacturer
Orthogonal Frequency Division Multiplexing (OFDM) is a method of encoding digital data on multiple carrier frequencies. OFDM is a frequency-division multiplexing (FDM) scheme used as a digital multi-carrier modulation method. A large number of closely spaced orthogonal sub-carrier signals are used to carry data on several parallel data streams or channels. Each sub-carrier is modulated with a conventional modulation scheme (such as quadrature amplitude modulation or phase-shift keying) at a low symbol rate, maintaining total data rates similar to conventional single-carrier modulation schemes in the same bandwidth.


Open Systems Interconnection networking model


Pseudonym Certificate Authority. Issues short-term pseudonym, identification, and application certificates to devices. Individual PCAs may be, e.g., limited to a particular geographic region, a particular manufacturer, or a type of device.

TPM contains several Platform Configuration Registers (PCRs) that allow a secure storage and reporting of security relevant metrics.

In telecommunications, the term protocol data unit (PDU) has the following meanings:

  • Information that is delivered as a unit among peer entities of a network and that may contain control information, such as address information, or user data.
  • In a layered system, a unit of data which is specified in a protocol of a given layer and which consists of protocol-control information and possibly user data of that layer.
Policy Generator. Maintains and signs updates of the Global Policy File (GPF), which contains global configuration information, and the Global Certificate Chain File (GCCF), which contains all trust chains of the SCMS.
Path History
PHY is an abbreviation for the physical layer of the OSI model and refers to the circuitry required to implement physical layer functions. A PHY connects a link layer device (often-called MAC as an abbreviation for media access control) to a physical medium such as an optical fiber or copper cable.
A Protocol Implementation Conformance Statement (PICS) is a structured document which asserts, which specific requirements are met by a given implementation of a protocol standard.


A Public Key Infrastructure (PKI) is a set of hardware, software, people, policies, and procedures needed to create, manage, distribute, use, store, and revoke digital certificates and manage public-key encryption.

Physical Layer management Entity


Pre-Linkage Value


Proof of Concept
Path Prediction
A pulse per second (PPS or 1PPS) is an electrical signal that has a width of less than one second and a sharply rising or abruptly falling edge that accurately repeats once per second. PPS signals are output by radio beacons, frequency standards, other types of precision oscillators and some GPS receivers.Precision clocks are sometimes manufactured by interfacing a PPS signal generator to processing equipment that aligns the PPS signal to the UTC second and converts it to a useful display. Atomic clocks usually have an external PPS output, although internally they may operate at 9,192,631,770 Hz. PPS signals have an accuracy ranging from a 12 picoseconds to a few microseconds per second, or 2.0 nanoseconds to a few milliseconds per day based on the resolution and accuracy of the device generating the signal.


The Provider Service Identifier (PSID) is a four-byte numeric string used by the IEEE 1609 set of standards to identify a particular application service provider that announces that it is providing a service to potential users of an application or service.


The PKI role that assures valid and correct registration is called a registration authority (RA). An RA validates and processes requests from devices. From those, it creates individual requests for certificates to the PCA. The RA implements mechanisms to ensure that revoked devices are not issued new certificates, and that devices are not issued more than one set of certificates for a given time period. In addition, the RA provides authenticated information about SCMS configuration changes to devices, which may include a component changing its network address or certificate, or relaying policy decisions issued by the SCMS Manager. Additionally, when sending pseudonym certificate signing requests to the PCA or forwarding information to the MA, the RA shuffles the requests/reports to prevent the PCA from taking the sequence of requests as an indication for which certificates may belong to the same batch and the MA from determining the reporters' routes.

In a PKI there are two types of certificate authorities (CAs), root CAs (RCA) and intermediate CAs. An RCA is the root at the top of a certificate chain in the SCMS and hence a trust anchor in a traditional PKI sense. It issues certificates for ICAs as well as SCMS components like PG and MA. An RCA has a self-signed certificate, and a ballot with a quorum vote of the electors establishes trust in an RCA. RCA certificates must be stored in secure storage that is usually referred to as a Trust Store. An entity verifies any certificate by verifying all certificates along the chain from the certificate at hand to the trusted RCA. This concept is called chain-validation of certificates and is the fundamental concept of any PKI. If the RCA and its private key are not secure, then the system is potentially compromised. Due to its importance, an RCA is typically off-line when not in active use.

Revocation Identifier Field

Radio frequency (RF) is any of the electromagnetic wave frequencies that lie in the range extending from around kHz to 300 GHz, which include those frequencies used for communications or radar signals.


RSA is one of the first practical public-key cryptosystems and is widely used for secure data transmission. In such a cryptosystem, the encryption key is public and differs from the decryption key, which is kept secret. In RSA, this asymmetry is based on the practical difficulty of factoring the product of two large prime numbers. RSA is made of the initial letters of the surnames of Ron Rivest, Adi Shamir, and Leonard Adleman, who first publicly described the algorithm in 1977.


Road-side Equipment. Synonym for RSU. Equivalent to RSU definition in DSRC Roadside Unit (RSU) Specifications Document v4.1

Roadside Unit. Synonym for RSE
RTS/CTS (Request to Send / Clear to Send) is the optional mechanism used by the IEEE 802.11 wireless networking protocol to reduce frame collisions introduced by the hidden node problem. Originally the protocol fixed the exposed node problem as well, but modern RTS/CTS includes acknowledgements (ACKs) and does not solve the exposed node problem.
Remote Vehicle
SAE International, initially established as the Society of Automotive Engineers (SAE), is a U.S.-based, globally active professional association and standards developing organization for engineering professionals in various industries. Principal emphasis is placed on transport industries such as automotive, aerospace, and commercial vehicles.
A Service Access Point (SAP) is an identifying label for network endpoints used in Open Systems Interconnection (OSI) networking.

Augmentation of a global navigation satellite system (GNSS) is a method of improving the navigation system's attributes, such as accuracy, reliability, and availability, through the integration of external information into the calculation process. There are many such systems in place and they are generally named or described based on how the GNSS sensor receives the external information. Some systems transmit additional information about sources of error (such as clock drift, ephemeris, or ionospheric delay), others provide direct measurements of how much the signal was off in the past, while a third group provide additional vehicle information to be integrated in the calculation process.

A satellite-based augmentation system (SBAS) is a system that supports wide-area or regional augmentation through the use of additional satellite-broadcast messages. Such systems are commonly composed of multiple ground stations, located at accurately-surveyed points. The ground stations take measurements of one or more of the GNSS satellites, the satellite signals, or other environmental factors which may impact the signal received by the users. Using these measurements, information messages are created and sent to one or more satellites for broadcast to the end users.

Service Channel


The Security Credential Management System (SCMS) is the term used to identify the PKI used in the U.S. V2X system.

SCMS Manager

Intrinsically central component of the SCMS. The SCMS Manager ensures efficient and fair operation of the SCMS, defines organizational and technical policies, and sets guidelines for reviewing misbehavior and revocation requests to ensure that they are correct and fair according to procedures.


Simple Network Management Protocol (SNMP) is an Internet-standard protocol for collecting and organizing information about managed devices on IP networks and for modifying that information to change device behavior. Devices that typically support SNMP include routers, switches, servers, workstations, printers, modem racks and more.

SNMP is widely used in network management for network monitoring. SNMP exposes management data in the form of variables on the managed systems organized in a management information base which describe the system status and configuration. These variables can then be remotely queried (and, in some circumstances, manipulated) by managing applications.


Simple Object Access Protocol (SOAP) is a messaging protocol that allows programs that run on disparate operating systems (such as Windows and Linux) to communicate using Hypertext Transfer Protocol (HTTP) and its Extensible Markup Language (XML).

SQL (Structured Query Language) is a standard interactive and programming language for getting information from and updating a database.
SSL (Secure Sockets Layer) is the standard security technology for establishing an encrypted link between a web server and a client. This link ensures that all data passed between the web server and clients remain private and integral.
SSP (Service Specific Permission) is a field that encodes permissions relevant to a particular certificate holder.
In IEEE 802.11 (Wi-Fi) terminology, a station (STA) is a device that has the capability to use the 802.11 protocol. For example, a station may be a laptop, access point or Wi-Fi phone. Generally in wireless networking terminology, a station, wireless client and node are often used interchangeably, with no strict distinction existing between these terms. A station may also be referred to as a transmitter or receiver based on its transmission characteristics. IEEE 802.11-2007 formally defines station as: Any device that contains an IEEE 802.11-conformant media access control (MAC) and physical layer (PHY) interface to the wireless medium (WM).


International Atomic Time (TAI, from the French name Temps Atomique International) is a high-precision atomic coordinate time standard based on the notional passage of proper time on Earth's geoid. It is the basis for Coordinated Universal Time (UTC), which is used for civil timekeeping all over the Earth's surface, and for Terrestrial Time, which is used for astronomical calculations. As of 30 June 2015 when another leap second was added, TAI is exactly 36 seconds ahead of UTC. The 36 seconds results from the initial difference of 10 seconds at the start of 1972, plus 26 leap seconds in UTC since 1972.


The Transmission Control Protocol (TCP) is a core protocol of the Internet Protocol Suite. It originated in the initial network implementation in which it complemented the Internet Protocol (IP). Therefore, the entire suite is commonly referred to as TCP/IP.

The Trusted Computing Group is a group formed by AMD, Hewlett-Packard, IBM, Intel and Microsoft to implement Trusted Computing concepts across personal computers.TCG's original goal was the development of a Trusted Platform Module (TPM), a semiconductor intellectual property core or integrated circuit that conforms to the trusted platform module specification put forward by the Trusted Computing Group and which is to be included with computers to enable trusted computing features.
Technical Component of the SCMS Manager


Traveler Information Message as described in SAE J2735.


Transport Layer Security (TLS) is a protocol that ensures privacy between communicating applications and their users on the Internet. When a server and client communicate, TLS ensures that no third party may eavesdrop or tamper with any message. TLS is the successor to the Secure Sockets Layer (SSL).


Traffic Management Center.
Trusted Platform Module (TPM) is an international standard for a secure cryptoprocessor, which is a dedicated microcontroller designed to secure hardware by integrating cryptographic keys into devices.

A true random number generator (TRNG) is a device that generates random numbers from a physical process, rather than a computer program. Such devices are often based on microscopic phenomena that generate low-level, statistically random "noise" signals, such as thermal noise, the photoelectric effect, involving a beam splitter, and other quantum phenomena. These processes are, in theory, completely unpredictable, and the theory's assertions of unpredictability are subject to experimental test.

The main application for electronic hardware random number generators is in cryptography, where they are used to generate random cryptographic keys to transmit data securely.

Timing Synchronization Function (TSF) is specified in IEEE 802.11 wireless local area network (WLAN) standard to fulfill timing synchronization among users. A Timing Synchronization Function (TSF) keeps the timers for all stations in the same Basic Service Set (BSS) synchronized.
In telecommunications, transmission (abbreviation: Tx) is the process of sending and propagating an analogue or digital information signal over a physical point-to-point or point-to-multipoint transmission medium, either wired, optical fiber or wireless.


The United States Department of Defense (USDOD or DoD) is an executive branch department of the federal government of the United States charged with coordinating and supervising all agencies and functions of the government concerned directly with national security and the United States Armed Forces. It is headquartered at the Pentagon in Arlington, Virginia, just outside of Washington, D.C.


The United States Department of Transportation (USDOT or DOT) is a federal Cabinet department of the U.S. government concerned with transportation. It was established by an act of Congress on October 15, 1966, and began operation on April 1, 1967.


Universal Time (UT) is a time standard based on Earth's rotation. It is a modern continuation of Greenwich Mean Time (GMT), i.e., the mean solar time on the Prime Meridian at Greenwich, London, UK. In fact, the expression "Universal Time" is ambiguous (when accuracy of better than a few seconds is required), as there are several versions of it, the most commonly used being Coordinated Universal Time (UTC) and UT1. All of these versions of UT, except for UTC, are based on Earth's rotation relative to distant celestial objects (stars and quasars), but with a scaling factor and other adjustments to make them closer to solar time. UTC is based on International Atomic Time, with leap seconds added to keep it within 0.9 second of UT1.

UT1 is the principal form of Universal Time. While conceptually it is mean solar time at 0° longitude, precise measurements of the Sun are difficult. Hence, it is computed from observations of distant quasars using long baseline interferometry, laser ranging of the Moon and artificial satellites, as well as the determination of GPS satellite orbits. UT1 is the same everywhere on Earth, and is proportional to the rotation angle of the Earth with respect to distant quasars, specifically, the International Celestial Reference Frame (ICRF), neglecting some small adjustments. The observations allow the determination of a measure of the Earth's angle with respect to the ICRF, called the Earth Rotation Angle (ERA, which serves as a modern replacement for Greenwich Mean Sidereal Time). UT1 is required to follow the relationship

ERA = 2π(0.7790572732640 + 1.00273781191135448Tu) radians, where Tu = (Julian UT1 date - 2451545.0)


Coordinated Universal Time (UTC), is the primary time standard by which the world regulates clocks and time. It is within about 1 second of mean solar time at 0° longitude; it does not observe daylight saving time. It is one of several closely related successors to Greenwich Mean Time (GMT). For most purposes, UTC is considered interchangeable with GMT, but GMT is no longer precisely defined by the scientific community.

UTC was officially formalized in 1960 by the International Radio Consultative Committee in Recommendation 374, having been initiated by several national time laboratories. The system was adjusted several times until leap seconds were adopted in 1972 to simplify future adjustments. A number of proposals have been made to replace UTC with a new system that would eliminate leap seconds, but no consensus has yet been reached.

The current version of UTC is defined by International Telecommunications Union Recommendation (ITU-R TF.460-6), Standard-frequency and time-signal emissions and is based on International Atomic Time (TAI) with leap seconds added at irregular intervals to compensate for the slowing of Earth's rotation. Leap seconds are inserted as necessary to keep UTC within 0.9 seconds of universal time, UT1.

Vehicle-to-Infrastructure (V2I). See V2X
Vehicle-to-Vehicle (V2V) is an automobile technology designed to allow automobiles to "talk" to each other. In the US the systems will use a region of the 5.9 GHz band set aside by the United States Congress in 1999. V2V is also known as VANET (vehicular ad hoc network). It is a variation of MANET (Mobile ad hoc network), with the emphasis being now the node is the vehicle.
Vehicle to Vehicle System Engineering and Vehicle Integration Research for Deployment (CAMP Project)


Vehicle-to-everything (V2X) communication is the passing of information from a vehicle to any entity that may affect the vehicle, and viceversa. It is a vehicular communication system that incorporates other more specific types of communication as V2I (Vehicle-to-Infrastructure), V2V (Vehicle-to-vehicle), V2P (Vehicle-to-Pedestrian), V2D (Vehicle-to-device) and V2G (Vehicle-to-grid).


Vehicle Infrastructure Integration Consortium

Verify on Demand


A Virtual Private Network (VPN) extends a private network across a public network, such as the Internet. It enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network, and, thus, are benefiting from the functionality, security and management policies of the private network.A VPN establishes a virtual point-to-point connection using dedicated connections, virtual tunneling protocols, or traffic encryption.

Vendor Specific Action
Vehicle Safety Communication - Applications (CAMP project)


Vehicle Safety Communications 3 (CAMP Consortium)

Vehicle Safety Communications 5 (CAMP Consortium)
Vehicle Safety Communications Security (Studies, CAMP projects)
The Wide Area Augmentation System (WAAS) is an air navigation aid developed by the Federal Aviation Administration (prime contractor Raytheon Company) to augment the Global Positioning System (GPS), with the goal of improving its accuracy, integrity, and availability.
Wide Area Network (WAN) is a computer network that spans a relatively large geographical area. Typically, a WAN consists of two or more local-area networks (LANs).


IEEE 802.11p is an approved amendment to the IEEE 802.11 standard to add Wireless Access in Vehicular Environments (WAVE), a vehicular communication system. It defines enhancements to IEEE 802.11 (the basis of products marketed as Wi-Fi) required to support Intelligent Transportation Systems (ITS) applications. This includes data exchange between high-speed vehicles and between the vehicles and the roadside infrastructure in the licensed ITS band of 5.9 GHz (5.85-5.925 GHz).


To define different WAVE communication zones, think of the term WAVE Basic Service Set (WBSS) as a unique identifier for each communication zone. Vehicles must associate with only one WBSS at a time.
GNU Wget (or just Wget) is a computer program that retrieves content from web servers, and is part of the GNU Project. Its name is derived from World Wide Web and get. It supports downloading via HTTP, HTTPS, and FTP protocols.


The World Geodetic System (WGS) is a standard for use in cartography, geodesy, and navigation including by GPS. It comprises a standard coordinate system for the Earth, a standard spheroidal reference surface (the datum or reference ellipsoid) for raw altitude data, and a gravitational equipotential surface (the geoid) that defines the nominal sea level.


The WAVE Management Entity (WME) represents another entity that is unique to WAVE standards and performs much of the operations unique to WAVE standards. For instance, when data frames are scheduled, the transmission channel must be defined along with QoS priorities. Those priorities must allow an emergency safety message to be transmitted at anytime with very limited latency. Management of frame queuing, priority channels and handling of safety messages are quite unique to WAVE standards. The WME handles those particular processing in coordination with other design entities.


WAVE Short Message


WAVE Service Advertisement


WAVE communication services provide data communications over two protocol stacks, namely; IPv6 and WAVE Short Message Protocol (WSMP). WSMP is unique to the WAVE standards and is designed for use by specialized applications like safety applications. Applications using WSMP may initiate a WBSS to configure the Service Channel (SCH) for their use. But availability of SCH is optional since WSMP can be exchanged on the Control Channel (CCH) even in the absence of WBSS (i.e., in a V2V scenario).