Which of the following is a characteristic of 3-D Secure technology?

3-D Secure technology is indeed characterized by its ability to enhance security for online payment transactions. This protocol provides an additional layer of authentication for online credit and debit card transactions, helping to ensure that the transaction is being made by the legitimate cardholder. When a user attempts to complete a transaction, they may be redirected to their card issuer's page, where they are prompted to enter a password or a code to verify their identity. This process reduces the likelihood of fraud and chargebacks associated with online purchases.

The other options do not accurately describe 3-D Secure technology. For instance, while encryption is important for securing data, it is not the primary function of 3-D Secure. Instead, 3-D Secure focuses on authenticating the user at the point of transaction and does not specifically deal with the encryption of data in transit. Additionally, 3-D Secure is not a form of symmetric encryption; instead, it deals with user authentication processes during transactions rather than the mechanisms of encryption itself. Lastly, it is not used for email security, as its purpose is specifically tied to securing online transactions rather than communication.