If you see a long string of characters at the beginning or end of an email message, what could it indicate?

Seeing a long string of characters at the beginning or end of an email message often indicates that the message is using Pretty Good Privacy (PGP) for encryption or signing. PGP is a program that provides cryptographic privacy and authentication for data communication. When an email is signed with PGP, it generates a digital signature that helps the recipient verify the identity of the sender and ensures that the message has not been altered in transit.

The long string of characters represents either the encrypted part of the message or the signature itself, making it clear that the email has undergone a security process to protect its contents. This string is a standard characteristic of PGP-encrypted messages and serves to maintain confidentiality and integrity during transmission.

Other choices, while related to security threats or software issues, do not specifically correlate with the presence of a long string of characters in the context described.