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Difference Between Public Key And Private Key

Published on 07-Apr-2023
In the realm of modern cryptography, private key, and public key are two technical concepts that are used to secure the electronic data of organizations, businesses, and corporations. For the purpose of cybersecurity, public key, and private key cryptography work together to provide a safe and trustworthy system for transmitting digital data.

Let us explore the difference between a public key and a private key, and their application in various cybersecurity-related aspects.

What Is a Private Key And How It Is Used?

A private key is a secret key that is used in cryptography to encrypt and decrypt digital data. It is called a private key because it is kept secret and known only to the owner/sender. Mainly, the private key is used in combination with a public key to create a secure channel between two parties for exchanging electronic data/records/documents.

In Private Key Cryptography or Symmetric Cryptography, a user uses the same key for encryption and decryption purposes. The private key is shared between the sender and recipient to communicate securely.

Private key cryptography is often used to encrypt sensitive information that is stored locally on a digital device, such as personal information, financial records, banking, property, or medical records, etc.

What Is a Public Key & How It Is Used in Cryptography?

A public key is a cryptographic key that is used to encrypt digital data and verify digital signature. It is called a public key because it is shared publicly and anyone can use it to encrypt data or verify digital signatures.

In Public Key Cryptography or asymmetric cryptography, a user uses a method of encryption that uses two separate keys for encryption and decryption. The public key is available to anyone who wants to send a message or data by using the intended recipient's public key. The private key, on the other hand, is kept confidential and known only to the recipient/owner. Public key cryptography is used to secure electronic data exchange, including emails, instant messages, and online transactions.

How A Public Key Cryptography Is Used To Create A Digital Signature

In order to secure electronic documents, records, or data, public key cryptography is often used to create a digital signature that can be used to validate the authenticity of the document.

A digital signature is a mathematical algorithm that is applied to a document, creating a unique identity of that particular record that can be used to verify its authenticity.

Digital signatures are created using public key cryptography, and they are often used to digitally sign documents, including office contacts, invoices, organizational records, and legal documents.

To ensure that digital signatures are legally binding, they must be created by certificate authorities. Certificate authorities are agencies that issue digital certificates that are used to validate the authenticity of signers. Hence, the prominent use of public key cryptography can be noticed in the creation of digital signatures.

What Is a Digital Signature Certificate DSC & Who Can Issue It?

A digital signature certificate is a digital form of a certificate that is used to verify the identity of the sender of an electronic document or message. It is equivalent to a handwritten signature and is used to provide assurance that the electronic data has not been altered in transit and that the sender is who they claim to be.

A DSC is provided by a Licensed Certificate Authority CA like Capricorn CA, which is approved and regulated by the Controller of Certifying Authority CCA, Government of India. There are several application modes through which you can apply for your DSC and obtain it after complete verification.

Use of Public & Private Keys In Signing Of Digital Documents

When signing a document using a digital signature, the private key is used to create a unique identifier/hash value that can be used to validate the authenticity of the document. The digital signature is attached to the document, and the recipient can use the public key to validate the signature and confirm that the document has not been tampered with.

Public key infrastructure PKI is a system of software, methods, and procedures that are used to manage public key encryption. PKI is used to secure electronic data and to provide a framework for the creation, validation, and management of digital certificates.


The private and public keys, both are two different types of cryptographic keys that serve the purpose of cybersecurity in securing the essential data, managing dsc and authenticity of the data. These keys are used in the signing of electronic data as well as encryption & decryption mechanisms. These keys play a significant role in the prevention of cyber threats and the authentication of records.