What is Asymmetric Encryption?

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What is Asymmetric Encryption?

Yash Kushwaha
Last updated on October 19, 2022

    When we discuss encryption, it resembles a door lock. You require a key to open the lock. This implies that only those who possess the key can open the door and obtain access to the object it is guarding. In this digital world, the key can be anything from a password to a code to a PIN.

    Data encryption is one of the most significant approaches to keeping sensitive and confidential information safe from being harmed or stolen. In a matter of encryption, it is not a single technique; instead, you will find various encryption methods. Among all, asymmetric encryption, commonly referred to as public key encryption, is one.

    This article aims at explaining to you about asymmetric encryption, how it works, its characteristics, pros and cons, and how it differs from symmetric encryption. Prior to all these, we shall briefly discuss what encryption exactly is.

    So, let us begin without further ado!

    What is Encryption?

    Encryption makes data unreadable to any party other than those authorized to decipher it. Technically speaking, it is the process of converting plaintext that only humans can read into ciphertext, which is not in a readable format. Simply put, encryption transforms readable data into random-looking data that is incomprehensible. A cryptographic key, or a collection of numbers that both the sender and recipient of an encrypted message agree upon, is needed for encryption.

    There are mainly two types of encryption, as follows:

    • Symmetric Key Encryption

    This type of encryption leverages the same key to encrypt and decrypt messages, making it less secure but easier to use. Additionally, one should use a safe way to pass the key from one party to another.

    • Asymmetric Key Encryption

    This kind of encryption is based on both public and private key encryption strategies. Public and private keys are used to encrypt and decrypt the communication. It is more secure than symmetric key encryption, despite being slower.

    What is Asymmetric Encryption?

    It is a sort of encryption method that encrypts and decrypts data sent between two parties across public, insecure channels (like the internet) using two different yet mathematically linked keys. In a word, it's all about protecting your sensitive information when you need to upload it to a website, send it over email, etc., so that it's not accessible to unauthorized people or entities (like cyber criminals).

    Because the two keys are mathematically connected but distinct (thus, asymmetric), this encryption method is also a component of asymmetric key cryptography and public key cryptography:

    • A public key is typically used to encrypt data, and all parties have knowledge about the public key.
    • The private key is only known to the key owner, which is used to decrypt the encrypted data.

    What does Asymmetric Encryption Do?

    This encryption method allows you to verify strangers you've never met through insecure public channels. As discussed earlier, it employs two different keys, unlike the symmetric encryption technique, which uses just one key to encode and decrypt data.

    For this reason, public key encryption is a crucial component of the framework for internet security. The framework of encryption and cybersecurity known as PKI (or Public Key Infrastructure) safeguards communications between the server (your website) and the client (the users). By enabling data interchange and verification between numerous servers and users, PKI is crucial in creating a trusted and secure business environment.

    You can leverage asymmetric encryption to

    • Verify the authenticity of individuals or groups
    • Asses the data for its integrity
    • Exchange symmetric keys

    Are you aware of the fact that you are currently using asymmetric encryption? Do you notice a security padlock icon on the left of the URL or HTTPS in the URL? This implies that you have visited a secure website that makes use of the secure TLS protocol and SSL/TLS certificates. This protocol uses public key encryption to validate a server’s authenticity and generate symmetric session keys.

    Characteristics of Asymmetric Encryption

    Let us now discuss some major characteristics of public key encryption here.

    • Protection of Information: This type of encryption ensures the security and integrity of data.
    • Keeps Information Private: It preserves data confidentiality because there is no need to disseminate the two keys if they are not shared.
    • Data Encryption and Key Exchange on Open Channels: The primary goal of asymmetric encryption is to encrypt data on open systems while maintaining data integrity and authenticity. However, since asymmetric Encryption uses two unique keys, no key exchange is necessary.
    • Keeping Digital Signatures Authentic: In public key cryptography, digital signatures are produced using two cryptographic keys that mutually authenticate one another. The person who creates the digital signature encrypts the data associated with it using a private key, and only the signer's public key can be used to decrypt it.
    • Asymmetric Large Encryption Keys: The public key encryption is safe, thanks to its long, distinctive, and arbitrarily generated numerical strings. Websites across the globe leverage SSL certificates to secure their website data. Since each website uses a different set of keys for encryption and decryption, the website have new SSL certicfactes. Imagine the randomness of the strings used to generate the keys, which makes each key different and unpredictable.
    • Strong Encryption Techniques: All of the well-known and safe essential exchange methods, including Diffie-Hellman, ElGamal, RSA, DSA, and ECC, fall under this type of encryption method. This procedure uses lengthy keys (1024-bit or 2048-bit), which improve client-server communication.
    • Initiator's Non-Repudiation: The sender, or the person who first shared the communication with others, cannot retract the information he has already sent. Thus, asymmetric Encryption continues to be superior to symmetric encryption.

    How does Asymmetric Encryption Work?

    This encryption method makes use of two unique but connected keys. Decryption requires the private key, while encryption requires the public key. The private key is designed to be private, as suggested by the name, and is available only to authenticated users so that they can decode the encrypted message.

    Let's look at an example to grasp this better.

    Imagine that you are a spy agency that needs to develop a secure way for your agents to report. They have their orders; you don't need two-way contact; all you need are frequent, thorough reports from them. By using public key encryption, you might provide the agents with public keys to encrypt their data while keeping a private key at the headquarters that would be required to decrypt everything. This offers an unbreakable one-way communication method.

    From the above image, you might have got a clear idea of how public key encryption works. You can encrypt the plain data, i.e., convert it into ciphertext, that you send over the internet using the public key. It is not possible to decrypt the ciphertext using the same public key. Instead, you need the corresponding private key to do so. In a nutshell, the sender should have the private key, whereas the receiver must have the private key.

    Symmetric vs Asymmetric Encryption

    Here is a table that highlights the differences between symmetric and asymmetric encryption:

    Key Differences

    Symmetric Key Encryption

    Asymmetric Key Encryption


    It requires only one key for both encryption and decryption.

    It requires two keys, one for encryption and the other for decryption.

    Cipher Text Size

    Cipher text is either the same size as the original plain text or somewhat smaller.

    Cipher text is the same size as or bigger than the original plain text.


    The encryption process moves quite quickly.

    The encryption process takes a long time.

    Data Size

    This method is employed when a lot of data needs to be transferred.

    It is utilized for small data transfers.


    It just offers confidentiality.

    It offers non-repudiation, confidentiality, and authenticity.

    Key Length

    The key used has a length of 128 or 256 bits.

    The key length is 2048 bits or longer.

    Resource Utilization

    Compared to asymmetric key encryption, symmetric key encryption uses fewer resources.

    Resource usage in asymmetric key encryption is high. It is effective because it can handle a lot of data.


    QUAD, RC4, AES, DES, and 3DES.

    Diffie-Hellman, RSA, and ECC algorithms

    The Advantages & Disadvantages of Asymmetric Encryption

    This encryption method comes with both advantages as well as disadvantages. Let us discuss the benefits and drawbacks below.


    • Convenience: It addresses the issue of sharing the encryption key. Private keys are kept confidential, whereas public keys are shared among all users.
    • Offers Message Authentication: Public key Encryption permits digital signatures, allowing the recipient to confirm that communication came from a specific sender.
    • Detection of Tampering: Using digital signatures in public key Encryption enables the receiver to determine whether the communication was tampered with while in transit. A message that has been digitally signed cannot be changed without the signature becoming invalid.
    • Enable Non-Repudiation: Signing a communication digitally is equivalent to physically signing a document. The communication has been acknowledged. Thus the sender cannot retract it.


    • Public keys should/have to be verified: Everyone must confirm that their public keys belong to them because no one can be certain that a public key belongs to the person it claims to represent.
    • Slow: When compared to symmetric Encryption, public key Encryption is slow. Not practical for use in mass message decryption.
    • Consumes more computer resources: When compared to single-key Encryption, it uses a lot more computer resources.
    • There is a risk of a widespread security breach: If an attacker learns a person's private key, they can read that person's whole history of communications.
    • It may be irreparable to lose a private key: Without a private key, it is impossible to decrypt any received messages.


    Here we have approached the end of our discussion on asymmetric or public key encryption. It is the cornerstone of internet security . Without it, most hackers find it as simple to take your sensitive data as it is to steal candy from a child. It offers a secure environment for the interchange of confidential data, increasing the expansion of e-commerce and giving digital projects a fresh perspective.

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    Symmetric and asymmetric encryption are the two types of encryption most often used today. The name is based on whether the same key is employed during encryption and decryption.

    Asymmetric Encryption, as the name suggests, uses two separate keys for the sender and the recipient. Data encrypted with the public key can only be decrypted with the private key, which is used in asymmetric Encryption, also referred to as public key Encryption.

    It is used in key exchange, email, and web security, as well as other encryption systems that call for key sales across a public network. Having two keys (public and private), the public key can be freely transferred without the private key's confidentiality being compromised.

    Asymmetric encryption, commonly known as public key encryption, actually uses a key pair: the public and private keys.

    Asymmetric-key algorithms function similarly to symmetric-key algorithms in that plaintext, and a key is combined, fed into the algorithm, and the algorithm outputs ciphertext.

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