What is Cryptography?
Updated on 13th Oct, 23 9.1K Views

With the increasing concern about data privacy, consumer safety is at an all-time high. Technology has made our lives easier, but it is essential to learn how to protect our data and stay up-to-date with emerging technologies.

Let’s have a look at the topics that will be discussed in this blog.

Before going any further, have a look at this video, in which our Cybersecurity specialists go over every detail of the technology.

What is Cryptography?

Cryptography is the study of encrypting and decrypting data to prevent unauthorized access. The ciphertext should be known by both the sender and the recipient. With the advancement of modern data security, we can now change our data such that only the intended recipient can understand it. 

Cryptography allows for the secure transmission of digital data between willing parties. It is used to safeguard company secrets, secure classified information, and sensitive information from fraudulent activity, among other things. Crypto means hidden and graph means writing.

Encryption is a fundamental component of cryptography, as it jumbles up data using various algorithms. Data encryption is the method of undoing the work done by encrypting data so that it can be read again. Cryptography is dependent on both of these methods.

In cryptography, a plaintext message is converted to ciphertext when using a technique, or a combination of numerical computations, that appear incomprehensible to the untrained eye.

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Types of Cryptography

Cryptography is classified into two categories based on the types of keys and encryption algorithms:

  1. Symmetric Key Cryptography (Secret key)
  2. Asymmetric Key Cryptography (Public key)

Let’s take a closer look at each type.

Symmetric Key Cryptography

Also known as Secret Key Cryptography, private key encryption encrypts data using a single key that only the sender and receiver know. The secret key must be known by both the sender and the receiver, but should not be sent across the channel; however, if the hacker obtains the key, deciphering the message will be easier. When the sender and the receiver meet on the handset, the key should be addressed. Although this is not an ideal method. Because the key remains the same, it is simpler to deliver a message to a certain receiver. The data encryption framework (DES Algorithm) is the most widely used symmetric key system.

For instance, Tom is sending a message to Mary that he does not want anyone else to see. He’d like to encrypt his message. That is simply because Tom and Mary exchange the same key. They will use the same key for encrypting and decrypting. Here’s how it works: First, Tom encrypts his signal with his key. His message has now been encrypted and scrambled. It can’t be read by anyone. When Mary receives the encrypted message, she decrypts it with the same key so she can read it in plaintext.

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Asymmetric key cryptography

Asymmetric key cryptography, also known as public-key cryptography, consists of two keys, a private key, which is used by the receiver, and a public key, which is announced to the public. Two different keys are used in this method to encrypt and decrypt the data. These two distinct keys are mathematically linked. They are sold in pairs. The public key is accessible to anyone, whereas the private key is only accessible to the person who generates these two keys.

For example, Bob wants to send an encrypted message to Alice, and they agree to encrypt his message using public-key encryption. The receiver initiates public key encryption to encrypt the sender’s message. The receiver, not the sender, initiates the public key method to encrypt the sender’s message. Everyone has access to the public key. The receiver, Alice, is the only one who has access to the private key. The following is how it works:

  • Step 1: Alice generates two keys: one public and one private. Alice stores the public key on a public key server that anyone can access.
  • Step 2: Alice informs Bob of the location of her public key.
  • Step 3: Bob obtains Alice’s public key by following Alice’s instructions.
  • Step 4: Bob composes a message and encrypts it with Alice’s public key. Bob sends Alice the encrypted message via the network.
  • Step 5: Alice decrypts Bob’s message using her private key.

Although Alice’s private key can confirm that no one read or changed the document while it was in transit, it cannot confirm the sender. Because Alice’s public key is available to the public, anyone can use it to encrypt his document and send it to Alice while posing as Bob. The digital signature is another technique that is required to prove the sender.

Digital Signature in Cryptography

A digital signature is equivalent to a handwritten signature. It is an electronic verification of the sender. Digital signatures are commonly used for software distribution, financial transactions. The digital signature serves three purposes:

  1. Authentication: The process or action of proving the sender in cryptography
  2. Non-repudiation: The assurance that someone cannot deny the validity
  3. Integrity: The quality of the message sent and received as it is

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Cryptography Example

Let’s look at an example of cryptography to see what it is:

Samuel wishes to communicate with his colleague Yary, who is currently residing in another country. The message contains trade secrets that should not be accessed or seen by any third party. He sends the message via a public platform such as Skype or WhatsApp. The foremost aim is to create a secure connection.

Assume Evy, a hacker who has obtained access to the message. Evy can now change or corrupt the message before it reaches Yary. Evy alters the message that Yary receives. Neither Samuel nor Yary are aware of the underground work. The outcomes are dreadful.

Now, cryptography can help. It can aid in the security of the connection between Samuel and Yary. 

Now that we understand what cryptography is, let us learn how cryptography aids in the security of messages.

Samuel first converts a readable message or Plain text into a series of digits using various cryptographic algorithms to protect the message. He then encrypts the message with a key. The ciphertext is a term used in cryptography. Samuel uses the internet to send an encrypted message to Yary. If Evy gains access to it and modifies the message before it reaches Yary. Yary now requires a key to decrypt Samuel’s message. The message can be converted from cipher text to plain text using the decryption key.

Because Evy altered the plain text, the result of the decryption will be the original plain text as an error. 

The error indicates that the message has been changed and is no longer the original message. As a result, encryption is critical for secure communication.

Plain text is simply a human-readable message, text, or information.

Cipher text- It is the output of the input plain text that gets converted after the encryption process. Basically, Cipher text is a type of plain text that is unreadable.

Cryptography Example

History of Cryptography

The history of cryptography finds its roots in Egypt around 4000 years ago. The Egyptians used hieroglyphics, the oldest cryptography technique, to communicate with each other. Later, in 500 BC, the technique was modified by replacing the characters with alphabets based on some secret rule known to only a few. This rule came to be known as the key to decipher hidden codes or messages.

Later, in the 15th century, more sophisticated techniques evolved such as Vigenere cipher and coding machines like the Enigma rotor machine. Years later, cryptography was born!

Also read our blog on Quantum Cryptography that uses quantum mechanics principle to tranmit and encrypt data!

How does Cryptography work?

The functioning of cryptography revolves around cryptographic algorithms. Cryptographic algorithms or ciphers are mathematical functions that are combined with keys, such as phrase, digit, word, etc., to encrypt text. The effectiveness depends on the strength of the cryptographic algorithms and the secrecy level of the key.

Multiple complex combinations of algorithms and keys boost the effectiveness of a cryptosystem.

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Cryptography Techniques

Some major techniques of Cryptography are listed below:


One of the oldest techniques of cryptography, steganography involves hiding secret information or messages with no confidential status files in order to avoid detection. Decades ago, steganography was not as sophisticated as it is now. Earlier, invisible ink, slight variations, etc., were used to hide messages. But with the advent of technology, steganography has evolved as one of the commonly used techniques in cryptography.


Hashing converts data to be hidden into a unique string. Irrespective of the type or form of data, hashing can be used to hide it. Once hashing is performed, it cannot be decrypted by using just keys.

Simple codes

A language is used to hide the meaning of the sentences written in a different language. The message is written in such a way that it is hard to decipher. In a majority of cases, niche alphabets are used to make the message more complex to read.

Symmetric encryption

It is mainly used for encrypting and decrypting electronic data through a secret key. Substitution ciphers form the base of symmetric encryption. However, nowadays, symmetric encryption is much more than just substitution ciphers. Symmetric encryption is largely used when the message to be encrypted is quite sizable.

Asymmetric encryption

This type of encryption uses two keys, public key, and private key, to encrypt and decrypt plaintext. Anyone with the secret key can decrypt the message. Hence, asymmetric encryption uses two corresponding keys to ensure secrecy.

Also, look into our blog on Hill Cipher and learn more about cipher!

Cryptography Algorithms

Cryptography algorithms are the means of altering data from a readable form to a protected form and back to the readable form. Cryptographic algorithms are used for important tasks such as data encryption, authentication, and digital signatures.

Cryptography Algorithms

RSA Algorithm in Cryptography

RSA is an asymmetric cryptographic algorithm. RSA Algorithm that works on a block cipher concept that converts plain text into ciphertext and vice versa at the receiver side. If the public key of User A is used for encryption, we have to use the private key of the same user for decryption.

  • Step 1: Select two prime numbers p and q where p not equal to q.
  • Step 2: Calculate n= p*q and z=(p-1)*(q-1)
  • Step 3: Choose number e: Such that e is less than n, which has no common factor (other than one) with z.
  • Step 4: Find number d: such that (ed-1) is exactly divisible by 2.
  • Step 5: Keys are generated using n, d, and e
  • Step 6: Encryption
    c=m pow(e) mod n
    (where m is plain text and c is ciphertext)
  • Step 7: Decryption
    m= c pow(d) mod n
  • Step 8: Public key is shared and the private key is hidden.

Note: (e, n) is the public key used for encryption. (d, n) is the private key used for decryption

The RSA algorithm has the drawback of being quite inefficient in cases in which large volumes of data must be authenticated by the same virtual machine. A foreign entity must substantiate the dependability of authentication tokens. Data is routed through middlemen, who may corrupt with the cryptosystem.

DES Algorithm in Cryptography

Data Encryption Standard is a symmetric cipher algorithm and uses the block cipher method for encryption and decryption. DES is the landmark in cryptographic algorithms. It works based on Fiesta Cipher Structure.

DES operates on a plaintext block of 64 bits and returns ciphertext of the same size.

  • Step 1: Sub-key Generation
  • Step 2: Encryption

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Advantages and Disadvantages of Cryptography

Advantages of Cryptography

  • Some techniques such as hashing, are known to preserve the integrity of the message.
  • It is used to guard highly confidential information and data.
  • It offers protection from users not intended to have access to a message.
  • Digital signatures provide non-repudiation against disputes that arise in situations where the sender denies passing of the message.

Disadvantages of Cryptography

  • It can prove to be dangerous if the system design is not properly managed.
  • Sometimes, a strongly encrypted message cannot be read by even the intended or legitimate user. This has been known to happen in many cases.
  • The whole concept of cryptography relies on the complexity of mathematical algorithms. What if someone breaks through the complex algorithms, the entire cryptosystem would be vulnerable to threats.

Types of Attacks in Cryptography

There are two types of cryptography attacks, passive and active attacks.


In a passive attack, the intruder can only see the private data but can hardly make any changes to it or alter it. Passive attacks are more dangerous because the intruder only sees the message without altering it. Then no one will ever know that an attack is taking place, and their hidden messages will no longer be hidden.

  • Snooping: Also known as message content leakage, snooping is a nonaggressive attack where the intruder can only read a message. This jeopardizes the security goal of confidentiality.


In this type of attack, the intruder can alter the private data.


The intruder will try to gain as much access to the computer system as possible. Masquerade is an active attack that threatens the security goal of credibility.

Brute force attack

A brute force attack occurs when hackers use computers to feedback loop over each letter in a character set systematically. A character set can consist of letters, numbers, symbols, or anything else that the hackers may desire. In the most general terms, a brute force attack is a method of trial and error that attempts all possible password combinations. This method works well for short passwords, but it takes a long time to try all possible passwords.

Dictionary attack

It is a quick and easy password attack. Hackers generate thousands of candidate digests and their pre-matched plaintext passwords using a dictionary. These candidate digits are compared to those in a stolen digest file by hackers. If a match is found, they are given the password. Although this method appears to be feasible if done manually, computers are capable of processing millions of words in a matter of hours.

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Cryptography in Cybersecurity

Cybersecurity has continued to evolve into one of the most innovative technologies. Both Cybersecurity and cryptography are interrelated.

Cryptography is now being used to hold confidential data, including private passwords, secure online. It is now used by cybersecurity experts to foster innovation, ciphertext, as well as other protective measures that enforce but also insulate business and personal info.

 Applications of Cryptography

  • When communicating, people want and require privacy and security.
  • Historically, cryptography has been extensively used during military applications to keep sensitive information hidden from enemies. To connect with his generals on the battleground, Julius Caesar used a simple shift cipher.
  • As technology advances, our dependence on electronic systems grows, necessitating the development of more sophisticated techniques.
  • The majority of the methods and techniques for secure communication are provided by cryptography.


With the growing worry of losing one’s privacy. The safety of consumers is at an all-time high. Cryptography is the study of encrypting and decrypting data to prevent unauthorized access. The ciphertext should be known by both the sender and the recipient.

Cybersecurity has continued to evolve into one of the most innovative technologies.

At these significant stages, cryptography comes to the rescue. Having a solid foundation in cryptography basics allows us to secure our confidential data.

Whether you’d like to gain knowledge on cybersecurity for your personal use or your new career, you can sign up for a beginner lesson to provide you with a fundamental insight into the prevailing scene of data security.

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