Asymmetric encryption, also known as public key encryption, is a cryptographic technique that uses a pair of keys for encryption and decryption. Unlike symmetric encryption, asymmetric encryption uses two keys - a public key and a private key.
In asymmetric encryption, the public key is used for and the private key is used for decryption.
Public - Private Key Pairs
The public key is freely distributed and can be shared with anyone, while the private key is kept secret and known only to the owner.
The public key is used to encrypt messages, while the private key is used to decrypt them. These keys are mathematically related but cannot be derived from each other.
This means that data encrypted with the public key can only be decrypted with the corresponding private key, and vice versa.
Public Key
Security
Asymmetric encryption addresses the key distribution challenge of symmetric encryption by allowing users to freely share their public keys.
However, the private key must be kept confidential to ensure security.
One advantage of asymmetric encryption is that it allows for secure communications over channels.
Speed
Asymmetric encryption is slower and more computationally intensive than symmetric encryption due to the complexity of the mathematical operations involved, especially with longer key lengths.
One drawback of asymmetric encryption is that it is slower than encryption.
Common Asymmetric Encryption Standards
RSA (Rivest-Shamir-Adleman)
One of the oldest and most widely used asymmetric encryption algorithms. It's based on the difficulty of factoring large prime numbers.
DSA (Digital Signature Algorithm)
Primarily used for digital signatures, DSA is based on the difficulty of solving the discrete logarithm problem.
Elliptic Curve Cryptography (ECC)
ECC offers strong security with smaller key sizes compared to RSA. It's based on the mathematical properties of elliptic curves.
Diffie-Hellman Key Exchange (DH)
While not an encryption algorithm itself, DH is a key exchange protocol used to securely establish a shared secret key between two parties over an insecure channel.
Elliptic Curve Diffie-Hellman (ECDH)
A variant of Diffie-Hellman that uses elliptic curve cryptography for key exchange. It offers similar security benefits as ECC.
A common asymmetric encryption algorithm is .
Use cases for Asymmetric Encryption
Key Exchange
Asymmetric encryption securely exchanges keys in symmetric encryption systems, such as HTTPS connections, ensuring secure communication.
Digital Signatures
Asymmetric encryption creates and verifies digital signatures, ensuring authenticity and integrity for electronic documents and transactions.
Secure Email Communication
Asymmetric encryption secures email communication by encrypting messages and attachments, protecting sensitive information from eavesdroppers and hackers.
SSH Authentication
Asymmetric encryption in SSH protocols enables secure remote login and command execution on servers, allowing users to authenticate without transmitting passwords.
Certificate Authorities (CAs)
Asymmetric encryption is used by CAs to issue and validate digital certificates, establishing the authenticity and trustworthiness of websites, software, and online services.
Key exchange protocols like Diffie-Hellman are used in asymmetric encryption to securely establish a shared key.
