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How does Encryption work? Private Key vs Public Key

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  • 3 min read

With data leaks making the headlines every so often, privacy and security are on everyone’s mind. Encryption is an essential factor contributing to online safety.

Encryption involves converting data into a cryptographic code to evade unauthorised access. A key is a code that sets off the decryption algorithms.

A recipient’s public key is available to anyone who wants to send them an encrypted message. A private key, on the other hand, is secret and known only to the recipient. Based on these keys, two significant forms of encryption have taken shape.

Also read: What is PGP encryption and OpenPGP? How do they work?

Private Key Encryption

Also known as symmetric encryption, this system employs only private keys.

This algorithm uses the same key to both encrypt and decrypt data. Hence, it is a swift process.

However, this system is vulnerable to attack.

Malicious elements can steal or leak private keys. Additionally, there is no guarantee of your message reaching only the intended recipient if the message passes through unsafe channels.

The only possible way to counter this is by regularly changing and distributing the encryption key. But, unfortunately, key management becomes a logistical nightmare.

Public Key Encryption

Also known as asymmetric encryption, this system employs both private and public keys.

Every user has a private and public key that are distinct from each other but are mathematically linked.

The sender uses the public key of the receiver to encrypt the message. This encrypted data can be decoded only by the user’s private key, a complete secret.

Hence the message can pass through unsafe channels as nobody but the intended recipient has the means to decode it.

Furthermore, an evil user can’t determine anyone else’s private key, even if they know the public key.

The longer a private key is, the less susceptible the system is to fall prey to a brute force attack — however, significant computational power for generating strong private keys.

Due to high computational requirements, asymmetric encryption is slower than secret-key cryptography.

One can digitally sign their content using their private key. This signature is then verified by their public key. Digital signatures help to determine the authenticity of documents and data.

Neither system is perfect yet, but asymmetric encryption is generally regarded as the superior form. Though it requires more time and power, it does a great job protecting your data and privacy.

Also read: What is Keylogging? 6 ways to protect yourself

Akshaya R

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