Anyone who has planned a vacation or a business trip involving air travel to several different countries knows that travel documentation can be a big hassle. Every country has a different set of regulations governing visas, they\u2019re usually complex, and failure to understand and comply with them means you\u2019ll be blocked from entering your country of destination at the airport.\nThe problems this state of affairs creates for individual travellers are nothing compared to those it creates for the airline industry as a whole, which has to deal with roughly 1.5 billion international passengers annually. And when an airline makes a mistake, it affects the bottom line. To begin with, there is a fine of roughly $3,500 on average for every passenger who is turned back at a destination airport due to improper documentation. In addition, airlines are compelled to fly such passengers back to their point of departure at no cost, which means one less seat that could be sold to a paying customer. The International Air Transport Association estimates the total cost of documentation problems to be $750 million annually.\nNation states have an even higher stake. They are, after all, the entities responsible for creating travel documents in the first place, and they do so to enforce national policies related not only to tourism and business travel, but also to the number of foreign workers eligible for in-country employment. They also depend on the accuracy and efficacy of watch lists to prevent entry by criminals and other of ill intend. It's common knowledge that the current system is deficient in this regard.\nComplexity, Human Error\nThe travel documentation systems currently in place are extremely complex. To begin with, information is held in multiple databases (travel agencies, airlines, nation states), a situation which in itself defeats the concept of a single version of the truth.\u00a0 Furthermore, the permissions that travel documents confer are complicated and frequently vary based on the owner\u2019s nationality and the rules of the destination country. To cite one typical example, the rules for entering the Netherlands are entirely different for Irish, Australian, French and Austrian citizens.\nTo make matters worse, these complicated rules are administered by check-in personnel who work under constant time pressure to keep flights on schedule, and who have no forensic training in identifying fraudulent documents. Even some legitimate documents that appear valid are not. For example, a passenger may present a one-time visa that\u2019s already been used.\nThe best system for managing international travel documentation would be based on a single database. Beyond basic functionality, the key challenge to such a system would be ensuring trustworthiness among participant members who might not trust one another\u2014an inevitable consequence of world politics as they are today.\nBlockchain technology is ideal for achieving this goal.\nWhat Is Blockchain?\nIn the minds of many, blockchain technology is synonymous with Bitcoin and other cryptocurrencies, but this is a serious oversimplification. Blockchain was indeed developed to support Bitcoin, but in fact it has potential for a myriad of non-financial uses.\nBlockchain records transactions in time-stamped \u201cblocks,\u201d each one of which is connected to all the blocks that preceded its creation and all those that follow it. Blockchains are distributed in a peer-to-peer network, with an identical copy on every participating network node. Once a transaction has been recorded, no single participant can alter it. (To do so, all the previous and subsequent blocks would also have to be altered, an impossibility for all practical purposes.) Records on a blockchain are cryptographically secured, with a private key for each node.\nBlockchain technology has one other feature important for international travel documentation, known as \u201csmart contracts.\u201d These are essentially a set of business rules that execute a specific action when specific conditions are met. Initially designed for financial transactions, smart contracts could easily be used at the airport. For example, if a traveler a) has a valid ticket, b) a valid visa and c) is traveling within the time constraints of that visa, the boarding gate will open.\nThese features offer a number of important benefits for international travel.\n\nPut simply, no traveler can cheat. The records are permanent and can\u2019t be altered. Equally important, the exact same records reside on every node, eliminating potential disputes. Any attempt at tampering is immediately visible to all. This means, for example, that fake visas would be a virtual impossibility.\nThe chance for mistakes by check-in personnel is dramatically reduced, which in turn reduces the costs associated with those errors, as well as the chance that criminals can sneak through the system.\nRecords are secured using cryptography, and access privileges are limited to confirmed members in possession of private keys.\nBecause of blockchain technology\u2019s distributed nature, there is no single point of failure, and the system can never be down.\nSimple to use. Proof of identity is the only item that check-in personnel need to verify. Check-in personnel have no need to understand the complexities of visa types, country-specific rules and so on. Permissions and restrictions are already in the system. Eventually, I.D. verification could be accomplished through biometrics, with no need for physical documentation at all.\n\nIn sum, blockchain technology has the potential to dramatically improve the efficiency and efficacy of international travel documentation, while cutting costs as well. It\u2019s an area that needs to be explored.