Host Identity Protocol


The Host Identity Protocol (HIP) is a network technology protocol that separates the role of IP addresses into locator and identifier functions. The protocol enables connections between devices that use different networks by providing an additional encryption and authentication layer. HIP is used to enhance security in mobility and multihoming, thereby preventing certain types of attacks such as man-in-the-middle and identity spoofing.


The phonetics of “Host Identity Protocol” is: /hoʊst aɪˈdɛntɪti ˈproʊtəkɒl/

Key Takeaways

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  1. Security and Mobility: The Host Identity Protocol (HIP) is a network layer protocol that enhances security and mobility in IP network communications. This way, HIP decouples the end-point identifier and locator roles of IP addresses to improve security and mobility.
  2. Rendezvous Servers: For discovering and tracking mobile devices in real-time, HIP makes use of Rendezvous Servers (RVS). This provides a form of anonymization and helps manage IP addresses to allow seamless mobility and multi-homing.
  3. Reduced Complexity: Through its consistent naming and secured architecture, HIP reduces application complexity greatly. It uses cryptographic namespaces for secure identification and allows end-point mobility and multi-homing without any changes to the application layer.



The Host Identity Protocol (HIP) is a significant development in internet technology as it decouples the end-point identifier and locator roles of IP addresses to improve security and mobility. This protocol assigns cryptographic host identities to allow secure and authenticated identification, separating it from the locator function of an IP address. HIP furthermore supports mobility and multi-homing, enabling uninterrupted communication between hosts even when they switch networks or IP addresses. It allows for more secure connections, reducing the risks of man-in-the-middle attacks and identity spoofing, thereby enhancing overall cybersecurity.


The Host Identity Protocol (HIP) serves a dual purpose of enhancing mobility and multihoming with enhanced security across the internet. It’s essentially implemented to tackle the shortcomings of the Internet Protocol (IP), which unfortunately intertwines the roles of an IP address, making it function both as a locator and an identifier. This intertwining often creates vulnerabilities and challenges especially when there’s a change of location or when multiple networks are involved. HIP addresses these concerns by decoupling the dual role of the IP address and introducing a cryptographic-based identity for each host.When it comes to functioning, HIP uses a new kind of protocol – a Host Identity layer – which sits between the Internet (IP) layer and the Transport layer in the networking stack. This Host Identity Layer creates and manages a pair of cryptographic keys for each host, functioning as a secure identity for the host. It then maps this identity to its IP address. This methodology ensures that even if the IP address changes due to a change in the network or geographical location, the identity of the host remains unchanged. The stable identity not only ensures uninterrupted communication between hosts, irrespective of their location, but also significantly enhances secure networking. Hence, HIP proves to be incredibly valuable in mobile and distributed computing environments, providing seamless communication and improved security.


1. Mobile Networks: In mobile networks, Host Identity Protocol allows seamless roaming across various networks without disrupting the active communication. For example, in mobile VoIP services, this protocol is used to maintain connections even when the network changes, ensuring that the voice call is not dropped when moving between different Wi-Fi networks or between Wi-Fi and mobile data.2. Internet of Things (IoT): HIP can also be used in IoT implementations. For instance, HIP can enable secure communication between IoT devices by assigning them a unique identity irrespective of their IP addresses, enhancing security against address spoofing attacks.3. Multihoming: In the context of networking, multihoming refers to the ability of a device to connect to the internet via multiple ISPs for reliability or load balancing. Host Identity Protocol allows for secure and resistive connectivity in this situation, maintaining a single, permanent identity for the device even as its network address changes. The protocol can keep network sessions active even if one of the internet connections fails, making it beneficial for businesses that require high availability.

Frequently Asked Questions(FAQ)

**Q: What is Host Identity Protocol (HIP)?**A: The Host Identity Protocol (HIP) is a network protocol that separates the role of IP addresses for host identification from their locator functionality in an IP network. It improves security, mobility, multihoming, and privacy communication abilities for Internet-connected devices.**Q: How does the Host Identity Protocol work?**A: HIP introduces a cryptographic namespace into the IP protocol suite used to identify peers. This separates its role from identifying IP addresses from their locator functionality, which helps to improve security and mobility over an IP network. **Q: What are some benefits to using HIP?**A: HIP presents numerous benefits including improved security through end-to-end encryption and authentication, easier mobility, improved multihoming through the ability to use multiple paths, and enhanced privacy due to automatically changing identifiers.**Q: Can HIP improve Internet-connected devices’ mobility management?**A: Yes, HIP allows for efficient mobility and multihoming across both IPv4 and IPv6 networks, which introduces considerable flexibility for Internet-connected devices.**Q: How does HIP improve security for Internet communications?**A: HIP introduces a cryptographic security association between the source and destination, thereby making the communication immune to several types of threats, such as man-in-the-middle attacks, replay attacks, malicious hijacking and more.**Q: In which applications is HIP most beneficial?**A: : HIP is ideal for any application that requires secure, precise and quick mobility or multihoming. It is especially useful in distributed systems, mobile networks, multihome networking, and other similar applications.**Q: Is HIP compatible with both IPv4 and IPv6?**A: Yes, one of the major strengths of HIP is its ability to seamlessly work across both IPv4 and IPv6 networks.**Q: Where can HIP be deployed?**A: HIP can be deployed in any device, such as computers, servers, mobile devices, IoT devices, which communicates over the Internet, as it works over the Internet protocol suite.**Q: What is the relationship between HIP and DNS?**A: HIP uses a distributed database that stands separate from the DNS. However, DNS can be used to initially locate HIP hosts and to retrieve their Host Identity Tags. **Q: What is the future of HIP?**A: HIP remains an active area of research and is gaining more attention due to its potential benefits in terms of security, privacy, mobility and multihoming. As more sophisticated threats emerge, HIP could become a cornerstone in building more secure and reliable Internet.

Related Tech Terms

  • End-Host Mobility
  • Multi-Homing
  • Identity-Based Security
  • Locator/Identity Separation
  • Public Key Infrastructure

Sources for More Information


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