Introduction
Every day millions of messages are sent via different channels - Whatsapp, Facebook, Telegram, Instagram, just to mention a few of the popular ones. In these messages, we reveal so many things about our life many times without fear or hesitation. By sending your private information via the channels available without any worry you are trusting that it is kept safe and secure. But have you ever wondered how these messages are secured?
Well, this is where encryption comes in. You might not know this but encryption has been used as far back as when messages were still sent via telegraphs. The telegraph companies encrypted the transmitting messages with an algorithm known as the cipher. Now back to the present where modern messenger apps like WhatsApp all keep messages safe in a much different way.
Whether now or then the process of keeping the messages safe is still based on a concept known as cryptography. Cryptography is the protection of information with the use of codes so that only authorized persons can read, or process the information. Cryptography was coined by combining two words. The first one is 'crypt' which refers to vaults and a suffix 'graphy' which denotes "writing*
Cryptography goes beyond securing your daily chit-chat with your loved ones. It is a recognized concept in computer science used in a variety of digital processes. Just like in the past when it was used with telegraphs, cryptography still largely depends on the combination of mathematical concepts and algorithms. Cryptography can be achieved through different methods.
Types of cryptography
There are many ways to go about cryptography so the most common ones will be highlighted. They include:
Symmetric key cryptography: Also known as secret or private key cryptography in some quarters. This method involves the use of a single key for encryption and decryption by the sender and receiver. Most times the AES (Advanced Encryption System) form of this method is preferred due to its swift and streamlined approach.
Asymmetric key cryptography: This method of encryption involves the use of a number of keys that the sender and receiver utilize in both the encryption and decryption process. Each of them has a stored private key while there is also a public key. The public key is used in transmitting the message across networks. It can also be referred to as public-key cryptography and it comes in different forms including RSA and DSA.
The hash function: This is the third major way via which encryption is carried out. It does not make use of any keys unlike the previous two. It is a mathematical equation that is fed an input of arbitrary length and outputs a result with a fixed length. The input goes through multiple rounds of hashing and the output received is the outcome of the last hashing round.
Quantum cryptography
In recent years cryptography is evolving and new methods of achieving it are now emerging. One of these methods is known as quantum cryptography. Unlike most ways of encrypting it is based on physics. Quantum cryptography makes use of quantum mechanics to encrypt information. It is carried out with a quantum computer via the use of quantum key distribution.
Quantum key distribution is a complex process but it can be simplified into five steps:
- The sender transmits with the use of a filter or polarizer which randomly provides one of four available bit designations.
- Photons are transmitted to a receiver. The function of the receiver is to use a beam splitter to read the polarization of each photon it receives. The corresponding beam splitter to a photon is not known.
- The receiver informs the sender about the beam splitters used for the transmitted photons using the sequence with which they traveled. The sender compares information received to the sequence of polarizers used in sending the photons.
- The photons which were read with wrong beam splitters are removed and the output sequence becomes the key.
Quantum cryptography is by far the most sophisticated, but no matter what type of cryptography is employed some criteria must be met to make it valid. These are known as cryptography objectives. The objectives of cryptography include, but not limited to;
Confidentiality: This means that all information cannot be deciphered by people who are not authorized to view or use it.
Integrity: information cannot just be discovered it can also be altered when intercepted. This objective means the method used must ensure that alteration is not carried out without swift and effective detection.
Non-repudiation: this means that the sender of the message is prevented from altering his/her are intentions in creating or sending the information.
Authentication: this means that both the sender and receiver of the information being transmitted can verify each other’s identity as well as the source and destination of the information in question.
If a cryptography method does not achieve all four of these then it is ineffective and should not be relied on.
More Applications of cryptography
Apart from securing messages, cryptography is applied in many more ways. These include:
Storage safety: It is important to guard information even while it is in storage. To achieve this data is saved in its encrypted format. This helps to protect the information from hackers.
Authenticating Identity: cryptography is also useful in verifying the identity of both senders and receivers. This is done in several ways such as with the use of passwords.
A peek into the future
So far the methods of encryption available have been sufficient in securing data. However, In recent years quantum computers have been developed. Though they are a great advancement they pose a huge threat to current cryptography methods. A quantum computer would have a public key decrypted in no time at all and that puts a lot of existing data at risk.
To fight this emerging problem quantum-secure cryptography(post-quantum cryptography) is currently being developed by some startups. One such is a startup from oxford university, PQShield. The team is working on encryption solutions created with today’s technology that would be able to combat the quantum risk. They are also trying to get people informed of the impending risk.