A company’s web filter is configured to scan the URL for strings and deny access when matches are found. Which of the following search strings should an analyst employ to prohibit access to non-encrypted websites?

The correct answer is http://. Non-encrypted websites use the HTTP protocol, and their URLs begin with "http://". By configuring the web filter to deny access when this string is found, the analyst effectively blocks access to all non-encrypted sites. "encryption=off" is not a standard URL component or filter string for identifying non-encrypted websites. URLs typically do not contain such parameters for encryption status. "www..com" would block all websites ending in .com that start with "www.", regardless of their encryption status, which is too broad and not specific to non-encrypted sites. ":443" refers to the standard port for HTTPS (encrypted) traffic. Blocking this port would prevent access to secure websites, which is the opposite of the objective.