What is the primary role of a public key in asymmetric encryption?

In asymmetric encryption, the primary role of a public key is to encrypt data in such a way that only the corresponding private key can decrypt it. This establishes a secure channel for communication, as anyone can use the public key to encrypt a message, but only the holder of the private key can decrypt and access the original content.

This mechanism ensures confidentiality, as eavesdroppers would find it practically impossible to decrypt the data without access to the private key. Additionally, it enables secure communication in various applications, such as secure email, digital signatures, and secure file transfer, where sensitive information needs to be protected from unauthorized access.

The other choices do not accurately reflect the essential function of a public key in asymmetric encryption. For example, while it may seem that the public key could allow for broader data encryption, its unique functionality lies in its paired relationship with the private key — ensuring that only specific recipients can read the encrypted data.