What should a sender do to send a recipient a file of personal data using asymmetric encryption?

Using the recipient's private key to encrypt is the basis for digital signatures proving sender identity, not for achieving confidentiality; anyone with the recipient's public key could then decrypt the message.

Encrypting with the sender's public key would mean only the sender could decrypt using their own private key, making the data inaccessible to the intended recipient.

Asymmetric encryption for confidentiality works by using the recipient's publicly available key to encrypt the data, ensuring only the recipient - who holds the matching private key - can decrypt it. This guarantees that even if the encrypted file is intercepted in transit, it cannot be read without the recipient's secret private key, which never needs to be shared.

Encrypting with the recipient's private key and decrypting with the sender's public key reverses the asymmetric model and produces a signature rather than a confidential message.