Asymmetric encryption is fundamental to various cyber security mechanisms because it allows two parties to communicate securely without having previously exchanged secret information. It’s used in numerous applications, such as securing communications over the internet with SSL/TLS, authenticating users and devices, and ensuring the integrity and non-repudiation of messages through digital signatures.
The strength of asymmetric encryption stems from the computational difficulty of deriving the private key from its corresponding public key. Algorithms commonly used for asymmetric encryption include RSA, ECC (Elliptic Curve Cryptography), and ElGamal. Despite its security benefits, asymmetric encryption is generally slower than symmetric encryption. Hence, it is often used alongside symmetric encryption in a hybrid approach.
How does asymmetric encryption work?
Put simply, asymmetric encryption requires one person to have the public key and the other to have the private key. The person with the public key encrypts the specific data from plaintext into ciphertext, and the person with the private key decrypts that data back into plaintext.
Asymmetric encryption, as it takes longer to encrypt than decrypt, is only used when there is a need for increased security. Since symmetric encryption doesn’t support identity verification, asymmetric encryption is also needed for that. An example of a service that uses asymmetric encryption is Bitcoin, as its transactions are related to the public key, but to move payments between accounts, you must have a private key.
What is the difference between symmetric and asymmetric encryption?
There are apparent differences between symmetric and asymmetric encryption. Asymmetric encryption uses two keys to encrypt/decrypt data: the public key and the private key. When you use the public key to encrypt data, you must use the private key to decrypt it. Symmetric encryption, on the other hand, only requires using a single key that shares both the public and private keys’ functions.
Asymmetric encryption has certain advantages over symmetric encryption. One of these advantages is that asymmetric encryption is more secure. Even if someone has the public key, without the private key, they will be unable to decrypt any data. Hackers must exert more effort as if they want to obtain useful data; they will have to acquire both keys. This layer of security does not exist for symmetric encryption, as it only has a singular key.
Another benefit of asymmetric encryption that symmetric encryption doesn’t have is that the public keys can be openly distributed. This is because losing them will not cause a security risk like losing a private key.
Key Characteristics:
- Key Pair: Uses two mathematically related keys, where one key encrypts the data and the other decrypts it.
- Non-Repudiation: Digital signatures provide proof of the sender’s identity and the integrity of the message.
- Key Distribution: This solution solves the key distribution problem by allowing anyone to encrypt with the public key, secure in the knowledge that only the holder of the private key can decrypt.
- Computational Security: Based on complex mathematical problems, it is computationally unfeasible to derive the private key from the public key.
Examples:
- Real-World Example: SSL/TLS protocols use asymmetric encryption to establish a secure session between a web browser and server, often indicated by a padlock icon in the browser’s address bar.
- Hypothetical Scenario: A diplomatic message is sent using asymmetric encryption. The sender uses the recipient’s public key to encrypt the communication, ensuring that only the recipient can decrypt the message with their private key upon receipt.
Related Terms:
- Symmetric Encryption: An encryption system where the same key is used for both encryption and decryption.
- Public Key Infrastructure (PKI): A framework for managing public keys and digital certificates, enabling secure electronic transfer of information.
- Digital Signature: An electronic signature that uses cryptographic techniques to provide assurances about the signatory and the authenticity of a message.
Learn better by watching a video? Here is a YouTube video explaining the concept, again using the Alice and Bob notation.
