Digital Passport & Contactless Immigration: The Blockchain Way

It is only after 2020, people started talking about digital COVID vaccination ‘passport’ to adapt to the new normal. The question is what this ‘passport’ would look like, it is either going to be a number or more popular QR code.

The barcode and QR code showed us a way to store information about any ‘object’ in a hidden manner but these codes are machine readable with a simple sensor like camera or LASER scanner.

It is surprising that our physical passport still exists with all these technological advancements. Let us look at what information your physical paper passports carry.

Passports stores three type of information, identity, nationality, & purpose of international travel. The unique identifier is your passport number. If you can cross reference the passport number, you can see Name, Date of Birth, Passport Issue Date, Expiry Date, Photo, and sample signature. There are many countries that also attach biometric information about the holder like fingerprints and facial recognition data.

All biometric data is stored in respective government databases. The database has existed since 2002, and all Interpol member countries have the option to check passports against it. – Well hold on! This is still a server and not a distributed ledger technology?

This means the database can someone hack into the database, theoretically, yes! Anything connected to the internet can be intercepted and hacked, the chances are less.

Can the passport be forged? Yes, it can be with not much effort. This is the reason the human traffickers to terrorists uses this route quite often and you see someone travelling with a dead person’s identity.

The next interesting step is when you use your passport and leave your country. At first, from the country you are leaving checks why are you leaving, are you the same person who is carrying the passport, do you have pre-approval to land in your destination country. At this point of time, the destination country does not guaranty your entry and does not know if you will arrive on this date.

On the other hand, when you land on your destination country, the same is checked again along with other reference data like if you have been to that country before, what all other countries you have travelled before, are you on some sanction list along with the authenticity of the passport. These are also checked while issuing the VISA but as some VISAs are long-term, the information stored earlier may have changed.

Did you see the multiple missing trust, duplication of efforts, wastage of resources?

Let us see how blockchain can help to simplify the process, reduce immigration time, and promote legitimate travels.

Issuance of passport will store the same information, but it should not be stored in a country specific server instead the data will be stored using distributed ledger technology to all the member countries United Nations. This will make the passport tampering nearly impossible even if there is some intended tampering by the highest level of the government. So, any change in passport data has be accepted and registered by all member nations.

More interestingly, this will eliminate the requirement of immigration! How?

Now, let me conceptually join the blockchain, distributed ledger, and crypto graphic hash function together. I will use an example from the above-mentioned problem. Imagine, I am Rohit Sharma, Nationality- Indian, travelling to United States for business.

1.    “Rohit Sharma, Indian, going to United States” <RSITUS>

2.    “Rohit Sharma, Indian, arrived United States” <RSIAUS><RSITUS>>

3.    “Rohit Sharma, Indian, going to India” <RSITUSI<RSIAUS><RSITUS>>>

4.    “Rohit Sharma, Indian, arrived India”<RSIAI<RSITUSI<RSIAUS><RSITUS>>>

So, if you have noticed, I have just used a kind of shorthand to the previous history. This shorthand is the just an abbreviation of the sentence. Now, if you take a closer look, alongside each entry, I have added a trail for the previous entry. To detect tampering, just check the initials match the word in the previous step.

This is still too simple to and you can see the initials, so let us add our knowledge about cryptography in this. I am using the cryptographic hash function. I am going to use the same SHA-256, that Bitcoin uses. You can also try this yourselves using https://www.movable-type.co.uk/scripts/sha256.html

 1.    “Rohit Sharma, Indian, going to United States” <RSITUS>

2.    268e9f382b0be895814b98895e62e3715a65696df5b6d7f1475392bc6db0bd22

3.    “Rohit Sharma, Indian, arrived United States” <RSIAUS><RSITUS>>

4.    fdbfcb649fe785c47e6fc4a5ce45d2ed46b552b6f24d84c96b8b4268e6008215

5.    “Rohit Sharma, Indian, going to India” <RSITUSI<RSIAUS><RSITUS>>>

6.    d35539a29afc380cd7714f207f513bc8ebfcfc49a6a50a680045b91da7964cd2

7.    “Rohit Sharma, Indian, arrived India”<RSIAI<RSITUSI<RSIAUS><RSITUS>>>

8.    1d1d8229a9084ed3d3fd505c90a95ec449b54ffffcfd8a6db33f4234d4332ead

 What this does it take any amount of input and then convert them into a 256-bit encrypted character. If you have input space in much bigger than the output space. SHA-256 is a cryptographic hash function. Mathematically, two random inputs having the same output is 2*256!

Now, how this is tamper proof? By making the ledger recursive, every entry contains a little copy of the previous entry. So, any attempts to tamper this would be discovered with the following the ways:

Even a tiny amount of tampering will produce inconsistency between the statement and the hash.

Collision-resistance and hiding means that one cannot tamper to produce the same hash

Recursivity means one has to tamper all along the chain to not be discovered

I am not going very detailed into the this as these should be enough information to solve our business problem.

So, if we try to use the blockchain and cryptographic hash function, we should be able to identify the identity, nationality, purpose without going through the lengthy unreliable processes.

So, finally what do you carry during travel? The answer is nothing apart from yourself! The biometric information stored in distributed ledger along with computer vision should able to travel without boundary.