What is a Cipher? Definition, Types, Examples and Methods

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What Is A Cipher
Updated on 15th Jul, 23 9.8 K Views

There are two kinds of cryptography in this world: cryptography which will stop your kid sister from reading your files, and cryptography which will stop major governments from reading your files. – Bruce Schneier


Generally, ciphers are categorized according to how they function and how their key is used for encryption and decryption. While stream ciphers employ a steady stream of symbols, block ciphers group symbols into a fixed-size message (the block).

When using a symmetric key technique or cipher, both encryption and decryption use the same key. Asymmetric key algorithms or ciphers use a distinct key for encryption and decryption.

Are you exploring Ciphers? then you have landed at the right place. In this blog, we will explain Cipher’s working, its types, and its uses.

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Table of Contents:

What is Cipher?

Cipher is a frequently used algorithm in cryptology, a subject concerned with the study of cryptographic algorithms. It is a method of encrypting and decrypting data.

  • The adoption of a symmetrical cipher will determine the secret or symmetric key encryption.
  • The symmetric algorithm applies the same encryption key and cipher to the data in the same way.
  • Symmetric ciphers are the foundation of symmetric key encryption, widely referred to as secret key encryption.
  • The goal might be to transform plain text to ciphertext or vice versa.
  • By transforming plaintext letters or other information into ciphertext, cyphers transform data. It is best to express the ciphertext as random information.
  • The cipher analyses the original and plaintext data to generate ciphertext that seems to be random data.
  • The same encryption key is applied to data, in the same way, using symmetric encryption methods, whether the goal is to convert plaintext to ciphertext or ciphertext to plaintext.

Ciphers have traditionally employed two basic forms of transformation:

  • Transposition ciphers maintain all of the original bits of data in a byte but reverse their order.
  • Substitution ciphers substitute specified data sequences with alternative data sequences. For example, one type of replacement would be to convert all bits with a value of 1 to bits with a value of 0, and vice versa.

The data generated by any method is known as the ciphertext.

  • In many networking protocols like TLS, or transport layer security, which permits network traffic encryption, modern cipher techniques use private communication.
  • Crypts are used by many communication technologies, including digital televisions, phones, and ATMs, to guarantee protection and confidentiality.

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How does a Cipher Work?

An encryption technique is used by ciphers to convert plaintext, which is a legible communication, into ciphertext, which seems to be a random string of letters.

  • In order to encrypt or decode bits in a stream, cyphers are sometimes called stream ciphers.
  • Alternately, they can use block ciphers, which process ciphertext in uniform blocks of a predetermined amount of bits.
  • The encryption algorithm is used by modern cipher implementations along with a secret key to modify data while it is encrypted.
  • Longer keys (measured in bits) make ciphers more resilient against brute-force attacks.
  • The more brute-force attacks that must be used to uncover the plaintext, the longer the key.
  • Although key length is not always correlated with cypher strength, experts advise that modern cyphers be built with keys of at least 128 bits or more, depending on the algorithm and use case.
Cipher Work
  • In real-world ciphering, the key is kept secret rather than the method because a key is such a crucial component of an encryption process.
  • Strong encryption methods are designed such that, even if someone is familiar with the process, deciphering the ciphertext without the required key should be challenging.
  • This means that in order for a cypher to work, both the sender and the receiver need to possess a key or set of keys.

In symmetric key approaches, the same key is used for both data encryption and decryption.

Asymmetric key algorithms use both public and private keys to encrypt and decrypt data.

Utilizing enormous numbers that have been paired but are not equal, asymmetric encryption, also known as public key cryptography (asymmetric).

An illustration of a key pair is shown below:

  • Everyone has access to the public key.
  • The private key, often known as the secret key, is kept confidential.

Either key can be used to encrypt a message; the opposite key used to encrypt the message is used to decode it.

When someone wishes to encrypt a message that can only be decoded by the author of the private key, they use the public key, although the author of the key pair utilizes the private or secret key to encryption or decryption of data.

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What is the Purpose of Ciphers?

The most used ciphers for securing internet communication are symmetric ones. They are also incorporated into several data-sharing network protocols.

For example, Secure Sockets Layer and TLS use ciphers to encrypt data at the application layer, especially when combined with HTTP Secure (HTTPS).

Virtual private networks that link remote workers or branches to corporate networks use protocols using symmetric key techniques to secure data transmission.

Symmetric cyphers are typically used in Wi-Fi networks, online banking and shopping, and mobile phone services to protect the privacy of user data.

Several protocols employ asymmetric cryptography to authenticate and encrypt endpoints.

The exchange of symmetric keys for the encryption of session data is likewise protected using it. These standards include the following:

  • HTTP
  • TLS
  • Secure Shell
  • Secure/Multipurpose Internet Mail Extensions
  • Open Pretty Good Privacy

Symmetric encryption is less safe than public key cryptography, but it also requires more computer power.

For improved performance, protocols commonly encrypt session data using symmetric key techniques.

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Types of Ciphers

Ciphers can be classified in a variety of ways, including the following:

Types of Ciphers
  • Block ciphers encrypt data in equally sized blocks.
  • Stream ciphers can be used on data streams that are often received and transferred via a network.

Two choices for ciphers are elliptical curve cryptography or conventional keys that are directly employed to key the ciphertext

  • When utilized with a 160-bit key, ECC may provide the same level of security as a traditional cipher, such as the one used in the RSA (Rivest-Shamir-Adleman) cryptosystem, which uses a 1,024-bit key.
  • Advanced encryption algorithms are meant to survive assaults even when the perpetrator is conscious of the cypher being employed.
  • Since plaintext was manually encrypted using ciphers, they were traditionally less secure against attack since they could be promptly inspected and broken using computer power.

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Examples of Cipher

The following are some well-known historical ciphers:

Examples of Cipher


This cipher is thought to have been used by Julius Caesar to securely transit with his people.

Every of the plaintext letters is moved a certain number of positions down the alphabet in this straightforward substitution cipher.

Caesar is supposed to have worked three shifts.

Substitution ciphers are frequently implemented by putting down the plaintext alphabet, followed by the ciphertext alphabet, shifted by the number agreed upon by those talking.

A three-letter shift places the letter D over the plaintext A, E above B, and so on. A basic form of a key is the number of characters moved.


This encryption is a replacement cipher that projects the plaintext alphabet back onto itself.

To put it another way, plaintext letter A is translated into ciphertext Z, plaintext letter B into ciphertext Y, plaintext letter C into ciphertext X, and so on.

Atbash is called after the Hebrew alphabet’s first and last letters. It is believed to have been used for hundreds of years.

Simple substitution

This one has been used for hundreds of years as well. It replaces each plaintext letter with a new ciphertext character, resulting in a 26-character key.

It varies from the Caesar cipher in that the enciphering alphabet is totally scrambled rather than just moved to a certain number of positions.


This cipher uses many replacement alphabets and is a polyalphabetic substitution cipher, which implies it is based on substitution.

The Vigenère encryption uses a series of interwoven Caesar ciphers that are based on the letters of a keyword.

The source text is scrambled using the Vigenère square or table.

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The Cipher is a technique for encrypting communications as a result. It translates a message by transforming the data that represents the message’s words and characters using the cipher algorithm. It is simple to automate and program the cipher algorithm, and ciphers may be created fast.

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