Cryptography

 

SALMAN CHEEMA (Y13)

This article was submitted as part of the WBGS Fuller Research Prize Competition 2022.

What is cryptography?

All around the world people use the internet for shopping, socialising and research. But how is our data protected when we use the internet? To ensure that your data is kept private, a process called cryptography is used. Cryptography is the process of securing data by scrambling important information into unreadable code.

How does cryptography work?

When you send a message across the internet, the message is often encrypted. The way this works is that your message is encoded so that it is unreadable. When the intended recipient receives your message, the encrypted message is converted back into the original message using a process known as decryption. Decryption works the same way as encryption but is the reverse process. Both the sender and the recipient use an encryption key to decode the encrypted message back to its original form. This key is a string of characters used within an encryption algorithm used to alter data. A public key is used by the sender to encrypt the message and a private key is used by the recipient to decrypt the message. This entire process helps protect the confidentiality of digital data transmitted through the internet. 

For example the following message can be encrypted as:

Hello World → Ebiil Tloia

This encryption is known as caesar cipher. In caesar cipher, each letter is shifted 3 to the left in alphabetical order.  So, a D would be replaced by an A, an E would be replaced by a B, a F would be replaced by a C and this pattern continues until a Z would be replaced by a W. A, B and C would be replaced by the letters X, Y and Z respectively.

The reverse process, decryption, can return this message back to its original state. In this example the message “Hello World” can be obtained by shifting each letter 3 to the right in alphabetical order.

Ebiil Tloia → Hello World

The process above uses caesar cipher which is a very simple encryption program and hence easy for an unintended user to decrypt. To prevent this, modern applications use complex mathematical formulae known as algorithms to enhance security. One way programs can improve security is by using a process known as multiple encryption. In multiple encryption, data is encrypted multiple times using the same or different encryption algorithm. This creates a stronger ciphertext. 

What are the uses of cryptography?

In our day to day lives, we use many applications where we input our personal information, whether it’s banking transaction information, private messages or secure web browsing. This private information is protected through encryption which prevents unauthorised users gaining access to your personal information. 

Here are some examples of the uses of cryptography:

• Authentication/digital signatures
• Electronic money
• Secure data transmissions across a network
• Disk encryption (Encrypts hard drive)

The history of cryptography

Although the use of modern cryptography tends to be digital, the concept of cryptography has lived for thousands of years. The first evidence known of the concept of cryptography was used in around 1900 BC in Egypt through hieroglyphics. There were some unusual hieroglyphic symbols in place of some ordinary hieroglyphic symbols. This use of cryptography was not for the exact same purpose as the cryptography (to hinder the meaning of the message). There has been more evidence of the use of cryptography in the most early of major civilisations but the next that I’ll focus on is in around 100 BC.

In around 100 BC, Julius Caesar was well known to use encryption to send private messages to his army generals. This encryption, well known as caesar cipher, was used to disguise these messages. This encryption method is described as above.

During the 16th century, an Italian cryptographer Giovan Battista Bellaso invented the Vigenere cipher in 1553, however the credit was attributed to the French cryptographer Blaise de Vigenere who created a similar cipher 33 years later. In the Vigenere cipher, the encryption key was repeated several times and the ciphertext was made by summing the message with the key character modulo 26. (Modulo is a mathematical operation in which the remainder is produced when a number is divided by another number, for example 23 = 2 mod 7). Just like caesar cipher, the Vigenere cipher would easily be broken. However, Vigenere’s cipher introduced the concept of encryption keys which are now used in modern cryptography. (However not in the same manner that Vigenere used them).

The Enigma machine, invented by the German engineer Arthur Scherbius, was used during World War II. The Enigma machine used several rotors which rotate as you type on the keyboard and display ciphertext. This cipher was then broken by Poland. Up until this point in time, most of the uses of cryptography were for military purposes, however, with the increase in the use of digital methods of storing data, businesses began to secure their data using cryptography to protect their data from their rival businesses. 

Until this day, cryptography continues to be used, being developed greater and greater. With the increase of the use of technology, our data must be protected but will cryptography continue to be used in the future or will there be an enhancement in the methods used to secure our personal information?