6.6 Explain common uses of encryption.
📘CompTIA ITF+ (FC0-U61)
When we talk about encryption, a key idea is understanding the difference between plain text and cipher text. These are two “states” of data.
1. Plain Text
- Definition:
Plain text is data in its original, readable form. This is the information that humans or programs can read directly. - Characteristics:
- Human-readable or understandable by programs.
- Vulnerable to interception if sent over networks without protection.
- Examples in IT:
- A password stored in a file without encryption.
- An email you type before it’s sent.
- A message in a chat app before it’s encrypted.
- Key point: Plain text is easy to read but not secure. If a hacker gets it, they can understand it immediately.
2. Cipher Text
- Definition:
Cipher text is data that has been transformed using encryption, making it unreadable to anyone who doesn’t have the proper key to decrypt it. - Characteristics:
- Looks like random letters, numbers, or symbols.
- Not human-readable.
- Requires a decryption key to convert back into plain text.
- Examples in IT:
- A password stored in a database after hashing/encryption.
- Emails sent through an encrypted email service (like TLS or PGP) appear as cipher text during transmission.
- Files encrypted using tools like BitLocker or VeraCrypt.
- Key point: Cipher text protects sensitive information, even if someone intercepts it.
3. How It Works in IT Environments
- Sending a Secure Email:
- You type your message → This is plain text.
- The email system encrypts it → It becomes cipher text in transit.
- The recipient decrypts it using a key → Back to plain text for reading.
- Storing Passwords:
- User types a password → Plain text.
- System encrypts it → Stored as cipher text.
- When the user logs in, system decrypts or hashes it → Checks against plain text input.
- File Encryption:
- File before encryption → Plain text or readable content.
- After encryption → Cipher text, unreadable without the key.
- Only authorized users with the key can read the original file.
4. Exam Tip
- Remember:
- Plain text = readable, unprotected
- Cipher text = unreadable, protected by encryption
- Many exam questions may ask:
- “Which is secure, plain text or cipher text?” → Cipher text
- “What do you need to read cipher text?” → Decryption key
5. Quick Visual
| State | Readable? | Secure? | Example in IT |
|---|---|---|---|
| Plain text | ✅ Yes | ❌ No | Password typed before saving |
| Cipher text | ❌ No | ✅ Yes | Password stored in database |
Summary:
Encryption is all about turning plain text into cipher text to protect information. In any IT environment—emails, passwords, files—data starts as plain text, becomes cipher text for security, and is decrypted back into plain text for authorized users.
