Encryption Coding
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Big Picture
When sending data from one location to another your data is goes through a series of points. Much like a subway located on the right you information stops at every point and then continues on. What is the problem? Well Imagine that you were passing notes through class about a class member. Consider this comic for a second |
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The image on the right is what happens when I run the "tracert" command on my computer to find out how many locations my connection goes through to reach YouTube
You can see my router IP on 192.168.1.1 Discussion: How is it that we can do internet banking, online sales and send personal emails even though our data goes to different points? What stops people being able to steal the data and easily hack your accounts? |
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Sally, Tom and Nancy are at school in the 80's. None of them had had cell phones or computer technology so communicating secretly was hard.
Sally who sits at the back of the class has a big crush on Tom. Tom during one Physics lecture turned and smiled at Sally. Sally was so excited and she wanted to tell Nancy (her best friend) immediately. However, She didn't want Tom to be aware that she was talking about him. She wants to send this message to Nancy: "Tom is super cute, and he just smiled at me." The Note has to be passed to Tom and then to Nancy. It could be thrown however the teacher could intercept it and read it out loud. Task: Figure out a way that Sally can send the message to Nancy without anyone intercepting it. |
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Ciphers and EncryptionComputers use Encryption to encrypt data so that if someone steals the message or your data they cannot access it unless they have a "key" or "cipher". This "cipher" is often linked to your password and email address.
Nancy send back this message: YXZH LCC EB FP JFKB 3 Task: Based on the cipher on the right what did Nancy send back to Sally? Tom is actually quite sneaky, Tom has been copying the notes and so far has 27 of them. Considering that Tom is actually quite good at physics and algorithms. Tom does not know what a caeser cipher is. Are the girls messages in danger of being intercepted? |
Caeser Cipher
Nancy added the number 3 to the end to let Sally know to rotate the alphabet 3 positions A-> A no rotation A = B 1 rotation A = C 2 rotations A = D 3 Rotations This is known as a Caeser Cipher. The Key is the number 3. The key could be anywhere between 1-25. (26 would rotate back to the start). |
Learning Tasks:
In One Note do the following:
1.) Briefly explain what encryption is and what it is used for (3-4 Sentences).
2.) List some of the problems that would occur if there was no such thing as encryption.
3.) Create a Ceaser Cipher, and encrypt a small sentence "Tom is quite good at physics" for example. Use a Number between 1-25 as an encryption key.
4.) Create a conversion table that shows how each letter in the sentence should be changed.
5.) Explain briefly what you have done through your example use the terms "plain text", "key, and "cipher text" in the relevant places.
6.) Describe what information a classmate would need to decrypt your message. (assuming they were doing it properly rather then trying to hack it.)
7.) Using the link here: csfieldguide.org.nz/en/chapters/coding-encryption/storing-passwords-securely/ describe why it is important to have secure passwords
In One Note do the following:
1.) Briefly explain what encryption is and what it is used for (3-4 Sentences).
2.) List some of the problems that would occur if there was no such thing as encryption.
3.) Create a Ceaser Cipher, and encrypt a small sentence "Tom is quite good at physics" for example. Use a Number between 1-25 as an encryption key.
4.) Create a conversion table that shows how each letter in the sentence should be changed.
5.) Explain briefly what you have done through your example use the terms "plain text", "key, and "cipher text" in the relevant places.
6.) Describe what information a classmate would need to decrypt your message. (assuming they were doing it properly rather then trying to hack it.)
7.) Using the link here: csfieldguide.org.nz/en/chapters/coding-encryption/storing-passwords-securely/ describe why it is important to have secure passwords
