What can users assume when they have an encrypted message?

The correct answer is that users can assume an encrypted message is unreadable without the proper key. This assumption stems from the fundamental principles of encryption, which is designed to protect the confidentiality of the information contained within a message. When a message is encrypted, its original content is transformed into an unreadable format that can only be reverted to its plain text form using a specific key meant for decryption.

Encryption algorithms are built on complex mathematical functions that ensure that without the correct decryption key, unauthorized users cannot access or understand the information. This reinforces the necessity of using proper credentials to maintain the security and integrity of the communication.

The other options do not align with the fundamental nature of encryption. For instance, suggesting that an encrypted message is the same as plain text overlooks the fundamental transformation encryption performs, while claiming it can be easily shared implies a lack of consideration for the sensitive nature of encrypted data. Additionally, stating that encrypted messages do not require authentication disregards the importance of ensuring that the messages truly originate from a verified sender, which is crucial for maintaining trust in communication. Therefore, recognizing that an encrypted message is unreadable without the proper key is essential for understanding how encryption safeguards information.