All You Need to Know About Asymmetric Encryption

With censorship becoming increasingly prevalent in today’s world, encryption has allowed everyone to have a  firm hold of their private information. Asymmetric encryption, also known as asymmetric-key cryptography, has become a staple in digital security, thanks to its multiple applications and varied advantages.

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What is the need for Asymmetric Key Cryptography?

Look at the following story to understand the need for asymmetric key cryptography. 

Joe is a journalist who needs to communicate with Ryan over long-distance messaging. If you have read Simplilearn’s article on symmetric encryption, you already know that there is a single key for both encryption and decryption of data in such a system. This key must be kept secret and should belong to the sender and receiver of the messages only. Because of the critical nature of the information, Joe uses symmetric encryption while sending his messages to prevent them from falling into the wrong hands.


However, the tricky part comes when Ryan needs to receive the decryption key for the encrypted data.


You face a critical problem here when it comes to the key exchange. The encrypted messages in transit are not a risk to either sender or receiver since unauthorized people can’t read the contents. But the decryption key, on the other hand, if intercepted, exposes all the information Joe has to disclose to Ryan.


This is the dilemma asymmetric encryption has fixed because of its multi-key architecture. Now, this tutorial will take you through its entire workflow.

What is Asymmetric Encryption?

Asymmetric encryption algorithms use two different keys for encryption and decryption. The key used for encryption is the public key, and the key used for decryption is the private key. Both the keys must belong to the receiver.


As you can see in the above image, using different keys for encryption and decryption has helped avoid the problem of key exchange, as seen in the case of symmetric encryption.

For example, if Alice needs to send a message to Bob, both the keys, private and public, must belong to Bob.


The process for the above image is as follows:

  • Step 1: Alice uses Bob’s public key to encrypt the message

  • Step 2: The encrypted message is sent to Bob
  • Step 3: Bob uses his private key to decrypt the message

To understand the asymmetric key cryptography architecture clearly, consider the process of sending and receiving letters via physical mailboxes. 

As shown below, anyone who has the postal address of the receiver (public key in our case) can send any message they want.


However, only the receiver can read all his/her messages thanks to the mailbox key that no other person can have.


This eliminates the need to exchange any secret key between sender and receiver, thereby reducing the window of exploitation.

Now that you understand the base terminology and process behind asymmetric key cryptography, this tutorial will take you through its applications.

Where is Asymmetric Key Cryptography used?

Asymmetric key cryptography has found use in many authentication domains thanks to its thorough identity verification process. Some applications are as follows:


  • Digital signatures: Verification of document origin and signature authenticity is possible today thanks to asymmetric key cryptography.

  • TLS/SSL handshake: Asymmetric key cryptography plays a significant role in verifying website server authenticity, exchanging the necessary encryption keys required, and generating a session using those keys to ensure maximum security. Instead of the rather insecure HTTP website format.

  • Crypto-currency: Asymmetric key cryptography uses blockchain technology to authorize cryptocurrency transactions and maintain the integrity of its decentralized architecture.

  • Key sharing: This cryptography category can also be used to exchange secret keys for symmetric encryption since keeping such keys private is of utmost importance in its system.

Why is Asymmetric Key Cryptography Called Public Key Cryptography?

The most significant advantage of using asymmetric key cryptography over symmetric encryption is the non-reliance on a single point of failure key. Since the key used to encrypt is already public, the key used to decrypt the data is supposed to be private and need not be shared. Asymmetric key cryptography is also called public-key cryptography because of its open nature.

This contrasts with symmetric encryption, where the single key used for both encryption and decryption is supposed to be kept secret, hence called private key cryptography.

Now, have a look at the most widely used asymmetric key cryptography algorithm today.

What Is RSA Encryption?

RSA encryption is an asymmetric encryption algorithm named after its founders (Rivest, Shamir & Adleman) that uses block cipher methodology to encrypt data. It has been adopted worldwide in many industries like VPNs, chat applications, browser authorization, and email encryption, to name a few.


RSA algorithm is also used for the signing of documents, where the sender can sign a document using his own private key, and the receiver verifies the document using the sender’s public key. Since both keys are mathematically linked, it is impossible to replace either of the keys with a fraudulent piece.

In the next section, you will go through the reasons why asymmetric key cryptography is widely accepted today as one of the most secure and reliable forms of encryption.

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What Are the Advantages of Using Asymmetric Key Cryptography?

Asymmetric encryption has a few advantages over symmetric encryption, which uses a single key for encryption and decryption of data. Some of these advantages are:


  • No key sharing: Asymmetric key cryptography overcomes the biggest flaw of symmetric key cryptography since it doesn’t need to exchange any keys that can decrypt data.
  • Proof of owner: Since it links the private and public keys together, a message is decrypted using a private key. It stands as evidence that the message originated from the rightful owner who has the private key.
  • Longer key lengths: Asymmetric encryption algorithms have key sizes up to 4096 bits that significantly increase the cipher and ciphertext security.
  • Tamper-proof: Hackers can’t modify data during transmission since doing so will prevent the receiver's private key from decrypting the message, thus informing the receiver that the message has been meddled with.

This brings an end to this tutorial on asymmetric-key cryptography.

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How Can Simplilearn Help You?

With this, you would have understood the importance of symmetric key cryptography in today’s internet sphere and its value in safeguarding our privacy and security. With many bases to cover in cybersecurity, cryptography is one of the most crucial aspects, even though several other topics are essential to excel as a cybersecurity expert.

Simplilearn offers a “Cybersecurity Expert” course designed to equip you with all the skills necessary to start or promote your career in cybersecurity. It doesn’t have any academic pre-requirements, and the introductory module will prepare beginners for the course ahead. Training for highly sought-after certifications like CompTIA Security+, CEH, CISM, and CISSP is at the forefront of this course, preparing you for the best jobs being offered in the industry.


This tutorial started by explaining the need for asymmetric encryption, its working and applications, justifications for being named public-key cryptography, and its advantages over its counterpart. Hope this article gave you clarity on Asymmetric encryption.

Do you have any questions for us? Please mention them in the comment section of this article and we’d be happy to have our experts answer them for you.

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