What is encryption?
Encryption is the process of scrambling data so that it becomes very difficult to unscrambleand understand without the correct key.
This allows information to be sent from one person to another person, without having to worry about others intercepting and understanding the message.
History of Encryption
Keeping messages secret has been necessaryfor thousands of years!
The earliest known use of cryptography is found in non-standard hieroglyphs carved into monuments in Egypt.
Encryption was used in WW2 to send messages between allies in a way that could not be understood by the enemy.
Encryption in the modern world
Encryption matters to you – not just intelligence officers and computer scientists.
Encryption is used in the following areas that affect you:
- Technical (wireless networking)
- Political (defence and security)
- Social (Electronic messages)
- Economical (banking and Internet shopping)
There are 7 billion people in the world.. Images what it would be like if anyone could collect and read information about you.. Even things you wouldn’t want to share with anyone!
Encryption – Key Terms
Plain text: Data that has not been encrypted and can be understood
Cipher text: Data that has been encrypted and cannot be understood.
Cipher: An algorithm used to encrypt or decrypt the data.
Key: Sometimes used along with the cipher
Caesar Cipher
The Caesar Cipher using a system whereby each letter of the plain text message is ‘shifted’ to change to another letter.
A ‘key’ is used to determine how many places each letter is to shift.
For example, if the key is 2 then the letter A becomes C, the letter B becomes D etc.
The word ‘HELLO’ encrypted with the Caesar cipher shift of3 is EHOOR.
Can you think of any ways to make the Caesar Cipher more complex so that its more difficult to decode a message? Think about what you could do to the key.
Pig Pen Cipher
The Pig Pen Cipher is a simple substitution cipher.
The letters are replaced by symbols which are determined by the position of the letter in a grid.
One such ‘grid’ is to use the position of letters on a mobile phone key pad.
Example letters:
The word ‘HELLO’ encrypted withthe Pig Pen Cipher is:
Encryption
Data on a computer or network may be intercepted by others.
Encryption scrambles the data so that it cannot be understood by others.
Strong Passwords
Passwords should be strong enough so thatthey cannot be guessed by others or bedetermined with a brute force attack.
We should passwords that are not too short and use a range of letters, numbers and symbols.
Anti-Malware Software
Anti-malware software allows you to scan your computer regularly and receive notifications if harmful malware is detected.
Firewalls
Firewalls can be configured to monitor thedata that enters a computer system (ornetwork) to check that it is allowed.Otherwise, it is denied.
Firewalls can also check data leaving a network (e.g. Smoothwall)
