ICDL Online Essentials cheat sheet

A URL has the form scheme://host/path; the scheme (http, https, ftp) tells the browser which protocol to use.

HTTPS encrypts traffic with TLS; the padlock icon indicates the connection is encrypted, not that the site is trustworthy.

The address bar accepts a URL or a search phrase; a bare word is passed to the configured default search engine.

Browser history records visited pages by date; clearing history does not delete downloaded files or bookmarks.

Cookies are small data files stored by a site; session cookies expire when the browser closes, persistent cookies have a set expiry date.

A bookmark (favourite) stores a URL for later reuse; bookmark folders organise entries and can be exported or imported.

Tabs let one browser window hold multiple pages; closing a tab does not close the browser window unless it is the last tab.

Private/incognito mode stops local storage of history and cookies on close but does not hide activity from the ISP or network.

Downloading a file copies it from a server to local storage; the browser may block or warn about executable file types.

A search engine indexes pages and matches query terms against that index; results are ranked by relevance signals, not verified for accuracy.

Quotation marks force an exact phrase match; a minus sign before a term excludes pages containing that term.

site: restricts results to one domain, filetype: restricts to one file format, and OR returns pages with either term.

A wildcard asterisk substitutes unknown words inside a quoted phrase.

Metadata such as author, publication date, and domain suffix (.gov, .edu, .org) helps judge a source's authority.

Cross-checking a claim against two or more independent sources reduces the risk of relying on a single unreliable page.

A page's currency is judged from its stated publication or last-updated date, not from the date it appears in search results.

Cached copies and archived versions show a page as it existed earlier, useful when the live page has changed or vanished.

Copyright applies to web content by default; reuse requires permission or a licence unless an exception such as fair use applies.

Email fields: To (primary recipients), Cc (visible copy), Bcc (hidden copy); Bcc recipients are not shown to other recipients.

Reply sends to the sender only; Reply All sends to the sender plus all other To and Cc addresses.

Attachments are encoded for transport, so file size limits apply; large files are often shared by link instead.

An email address has the form local-part@domain, for example [email protected].

A signature is text appended automatically to outgoing messages; it is not a security feature.

Spam filters score messages on content and sender reputation; a false positive places legitimate mail in the spam folder.

Real-time text chat differs from email in being synchronous: both parties must be online at the same time.

Netiquette rules include not typing in capitals (read as shouting) and trimming quoted text in replies.

A mailing list distributes one message to many subscribers; unsubscribing removes the address from future sends.

Phishing is a fraudulent message that impersonates a trusted party to steal credentials or data; check the actual sender address and link target.

Hovering over a link reveals its real destination before it is clicked.

A strong password is long and unpredictable; reusing one password across sites means one breach exposes many accounts.

Two-factor authentication adds a second proof (code, app, hardware key) beyond the password.

Malware includes viruses, worms, trojans, and ransomware; antivirus software detects known signatures and suspicious behaviour.

A firewall filters network traffic by rules, blocking unsolicited inbound connections.

A digital certificate binds a public key to a domain; a browser warning about an invalid certificate means the identity is unverified.

Personal data such as address, birth date, and bank details should not be posted publicly; privacy settings limit who can view a profile.

Social engineering manipulates people rather than systems, so technical defences alone do not stop it.