Cryptography: the key to protect data

The history of cryptography – that is, the art of encoding messages to hide them from prying eyes, goes back at least 4,000 years in time. There were even periods when it played a key role in events, as in World War II, when the brilliant mathematician Alan Turing was tasked with deciphering the codes sent by the germans.

But the truth is that technological advances have given this subject an importance it has never had before. It is no longer reserved for military leaders, intelligence agencies or the universe of espionage: today cryptography impacts our daily lives and is used to protect our email communications, our WhatsApp messages, the data of a corporate application, or to prevent anyone from accessing our bank accounts. The fields of its application are countless, but the objective is always the same: data protection.

Encrypted messages

Cryptography is responsible for encrypting a message in order to prevent its contents from being intercepted and read by someone unauthorized. The operation is successful when only the sender and the receiver are able to interpret the message: the former is in charge of encrypting it, i.e. transforming it into characters that do not make any sense to the naked eye, and the latter of decrypting it, i.e. returning it to its original meaning. These mechanisms are transparent to the user: they are executed automatically through algorithms and keys.

The starting point of modern cryptography was a publication by Claude Shannon in 1948, which transformed encryption techniques into advanced mathematical processes. For the next two decades, it was monopolized by the NSA (National Security Agency of the United States), which handled it as if it were a state secret. In 1975, the growing interest in computing brought cryptography out of the government basements and into the realm of market standards: DES (Data Encryption Standard) dates from 1975 and its successor, AES (Advanced Encryption Standard), dates from 2001.

Between the symmetrical and the asymmetrical

Among the most common types of cryptography are the so-called «symmetric», which uses only one key, previously known to all involved, for encryption and decryption, and the «asymmetric» or «public key», which uses two different mathematically linked keys, each of which handles only one of the operations. One of the keys is public and is available to any user, whether or not they are participating in the exchange. The other is private and cannot be revealed.

While the advantage of symmetric encryption is its simplicity and effectiveness, it also involves the risk that if a third party gains access to the key, it can decode the entire communication. Asymmetric encryption, on the other hand, has established itself over the years as a highly secure option. Its disadvantages? It requires very complex calculations and can slow down the process. Outside the purely theoretical scope, systems often use both to combine the speed of the symmetric model with the security of the public key model.

The challenge for the future

Cryptography faces an enormous challenge for the future: quantum computing. While this new advance promises the ability to solve any process no matter how complex, it has a side effect: quantum computers could make current cryptographic systems obsolete.

Of course, every new challenge comes with an effort to solve it. In this case, we are talking about post-quantum cryptography or PQCrypto: the search for new algorithms that resist this ultra-high performance computing, which the NIST (US National Institute of Standards and Technology) has been working on since 2016 and could have some notable breakthroughs in the remains of this year.

Thus, cryptography continues on its path to generate increasingly secure communications. That is precisely the key to everything.