What type of encryption utilizes both a public and a private key?

Asymmetric encryption is a cryptographic method that uses a pair of keys—a public key and a private key—to encrypt and decrypt data. This dual-key system allows for secure communication without the need for both parties to share a secret key in advance. The public key, which can be shared openly, is used to encrypt data, while the private key, which is kept secret, is used to decrypt the data that has been encrypted with the corresponding public key.

This method enhances security, especially in scenarios such as secure email communications and digital signatures, where the integrity and authenticity of a message must be verified.

In contrast, symmetric encryption employs a single key for both encryption and decryption, which necessitates secure key distribution and can pose risks if the key is intercepted. Stream and block encryption refer to methods of encrypting data streams or fixed-size blocks of data, respectively, but do not inherently involve the use of public and private key pairs.