When using asymmetric encryption, which key is used to encrypt the message and which key is used to decrypt it?

In asymmetric encryption, two distinct keys are utilized: a public key and a private key. The public key is freely distributed and can be used by anyone to encrypt a message intended for the key owner. In contrast, the private key is kept secret by the owner and is used to decrypt messages that have been encrypted with the corresponding public key.

When a message is encrypted using your colleague's public key, only your colleague’s private key can decrypt it, ensuring that only the intended recipient can access the original message. This encapsulates the essence of asymmetric encryption, providing both confidentiality and secure communication.

The choice that states your colleague's public key is used to encrypt the message while your colleague's private key is used to decrypt it accurately represents this mechanism of asymmetric encryption. This method guarantees that even if the public key is exposed, only the private key holder can access the encrypted information, thereby upholding the security principle inherent in asymmetric encryption systems.