Cryptography

Cryptography & Unplugged Encryption

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Unlocking the secret science of codes, ciphers, and digital data scrambling. Students progress from physical substitution ciphers to public-key encryption and modern hashing algorithms.

Level 1

Secret Symbols & Keys

Understand that messages can be encoded using symbol substitution keys.

Learning objective

Students will encode and decode short words using a 1-to-1 symbol substitution key (Pigpen or Emoji cipher).

Let's Go!

Step media

Learn

Cryptography is the science of secret writing! When you turn readable text (plaintext) into a secret code (ciphertext), you are 'encrypting' it. Anyone with the secret 'key' can turn it back into readable words ('decrypting'). In computing, symbols and codes allow people to transmit private messages. As you explore the interactive Cipher Wheel Simulator below, focus on how to decode an unknown short secret message using a substitution key without teacher assistance.

Interactive Simulator Sandbox
Cryptography Studio:Step 1 โ€ข Bronze Tier
๐Ÿ”
Step 1 โ€ข Bronze (Level 1): Secret Symbols - Matching Key Decoders

Match secret symbols and ancient runes against the substitution key to decode hidden letters and reveal the secret spy word.

In Progress
Interactive Cryptography Canvas
Caesar Shift: +3
CIPHERSHIFT: +0
---
๐Ÿงฎ Modulo 26 Shift Formula

Mathematical definition of the Caesar shift with alphabet wrap-around:

Encryption: $E_n(x) = (x + n) \pmod26$
Decryption: $D_n(x) = (x - n) \pmod26$
Where $x$ is the letter index (0 = A, 1 = B, ..., 25 = Z) and $n$ is the shift key.
๐Ÿ“Š Standard English Letter Frequencies

Expected distribution across 100,000 words in standard English corpora:

LetterFreq %LetterFreq %
E12.70%T9.06%
A8.17%O7.51%
I6.97%N6.75%
S6.33%H6.09%
R5.99%D4.25%
๐Ÿ”‘ Asymmetric RSA Key Pair Architecture

Mathematical foundation of public/private key trapdoor one-way functions:

Primes: $p, q$ (Large random secret prime numbers)
Modulus: $n = p \times q$ (Public component)
Public Key: $(e, n)$ โ€ข Private Key: $(d, n)$
Factoring $n$ back into $p$ and $q$ takes thousands of years for 2048-bit keys on classical computers.
โšก Cryptographic Hash Standard (NIST FIPS 180-4)
Algorithm:SHA-256 (Secure Hash Algorithm, 256-bit output)
Collision Resistance:$2^128$ operations required to find two different inputs with identical digests
Pre-image Resistance:Impossible to compute original text from digest ($2^256$ search space)

Apply Simulator Skills โ€ข Try it yourself

Decode the Spy Message

๐Ÿ”„Direct Simulator Transfer: Step 1 Tasks 1, 2 & 3

Now that you've practiced the virtual mechanics in the simulator above, apply those exact skills in your real computer environment:

๐ŸŒŸ Student Project GuideSuccess Criteria & WAGOLL (What A Good One Looks Like)โ–พ

๐ŸŽฏ Task Success Criteria (Rubric)

Foundation

Matches a symbol on a decoder sheet to its matching alphabet letter.

Developing

Encodes a 4-letter word using a grid-based symbol key.

Secure (Goal)

Decodes an unknown short secret message using a substitution key without teacher assistance.

Mastery

Creates a custom symbol substitution key and explains why keeping the key secret is necessary for privacy.

๐Ÿ‘€ What A Good One Looks Like (WAGOLL)

๐Ÿ“
Save to Your Website Portfolio:

When you finish creating your project in your software, copy the share link or take a screenshot and publish it onto your student portfolio website!

Reflect

๐ŸŽฏ

Self-Assessment & Reflection

What happens if someone steals your secret symbol key sheet?

๐ŸŸขSecure Level

Decodes an unknown short secret message using a substitution key without teacher assistance.

Learning check

Learning Check

In cryptography, what is a 'Key'?

Select the correct definition:

Answer correctly to unlock the next level.

Spot on! The key is the secret rule that unlocks and decodes the message.Try again! In ciphers, the key is the secret pattern or table that decodes the writing.
Teacher setup, curriculum links and progress descriptors

Spark support

Routine: See, Think, Wonder

Teacher notes: Facilitate the See, Think, Wonder routine for 2โ€“3 minutes. Encourage students to connect the prompt to Form (Symbols and codes allow people to transmit private messages.).

Achievement pathway

  • Foundation: Matches a symbol on a decoder sheet to its matching alphabet letter.
  • Developing: Encodes a 4-letter word using a grid-based symbol key.
  • Secure: Decodes an unknown short secret message using a substitution key without teacher assistance.
  • Mastering: Creates a custom symbol substitution key and explains why keeping the key secret is necessary for privacy.

Curriculum links

Curriculum strand: Everyday Digital Skills & Computational Science

Outcome: CY.01.B.1.1 โ€” Understand that messages can be encoded using symbol substitution keys.

PYP: Form ยท Symbols and codes allow people to transmit private messages.

Learner profile: Inquirer

Competency tags

  • cryptography
  • substitution-cipher
  • secret-codes
  • keys

Gate support

Accessibility alternative: Students may verbally explain or point to the correct answer for "In cryptography, what is a 'Key'?" with a teacher or teaching assistant.

Teacher override: allow

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Locked level

Level 2: The Caesar Shift Cipher

Complete the previous learning check to unlock this next level.

Level 2

The Caesar Shift Cipher

Apply numeric shift algorithms (Caesar Cipher) to encode and decode text.

Learning objective

Students will shift alphabet letters by a numerical key (+3, -3) to encrypt and decrypt messages.

Let's Go!

Step media

Learn

The Caesar Cipher is one of the oldest mathematical codes! You pick a shift number (like +3). 'A' becomes 'D', 'B' becomes 'E', and 'C' becomes 'F'. To read it, the recipient reverses the shift by subtracting 3. In computing, mathematical shifts create predictable algorithmic patterns. As you explore the interactive Cipher Wheel Simulator below, focus on how to decrypt a message using a Caesar shift of -3 and handles wrap-around letters (e.g. 'Z' shifting forward to 'C').

Interactive Simulator Sandbox
Cryptography Studio:Step 2 โ€ข Bronze Tier
๐Ÿ”
Step 1 โ€ข Bronze (Level 1): Secret Symbols - Matching Key Decoders

Match secret symbols and ancient runes against the substitution key to decode hidden letters and reveal the secret spy word.

In Progress
Interactive Cryptography Canvas
Caesar Shift: +3
CIPHERSHIFT: +0
---
๐Ÿงฎ Modulo 26 Shift Formula

Mathematical definition of the Caesar shift with alphabet wrap-around:

Encryption: $E_n(x) = (x + n) \pmod26$
Decryption: $D_n(x) = (x - n) \pmod26$
Where $x$ is the letter index (0 = A, 1 = B, ..., 25 = Z) and $n$ is the shift key.
๐Ÿ“Š Standard English Letter Frequencies

Expected distribution across 100,000 words in standard English corpora:

LetterFreq %LetterFreq %
E12.70%T9.06%
A8.17%O7.51%
I6.97%N6.75%
S6.33%H6.09%
R5.99%D4.25%
๐Ÿ”‘ Asymmetric RSA Key Pair Architecture

Mathematical foundation of public/private key trapdoor one-way functions:

Primes: $p, q$ (Large random secret prime numbers)
Modulus: $n = p \times q$ (Public component)
Public Key: $(e, n)$ โ€ข Private Key: $(d, n)$
Factoring $n$ back into $p$ and $q$ takes thousands of years for 2048-bit keys on classical computers.
โšก Cryptographic Hash Standard (NIST FIPS 180-4)
Algorithm:SHA-256 (Secure Hash Algorithm, 256-bit output)
Collision Resistance:$2^128$ operations required to find two different inputs with identical digests
Pre-image Resistance:Impossible to compute original text from digest ($2^256$ search space)

Apply Simulator Skills โ€ข Try it yourself

Caesar Cipher Wheel Challenge

๐Ÿ”„Direct Simulator Transfer: Step 2 Tasks 4, 5 & 6

Now that you've practiced the virtual mechanics in the simulator above, apply those exact skills in your real computer environment:

๐ŸŒŸ Student Project GuideSuccess Criteria & WAGOLL (What A Good One Looks Like)โ–พ

๐ŸŽฏ Task Success Criteria (Rubric)

Foundation

Counts forward 3 alphabet steps from 'A' to find 'D'.

Developing

Encrypts a word using a Caesar shift of +3.

Secure (Goal)

Decrypts a message using a Caesar shift of -3 and handles wrap-around letters (e.g. 'Z' shifting forward to 'C').

Mastery

Calculates reverse shift keys and explains why small shift keys are vulnerable to brute-force cracking.

๐Ÿ‘€ What A Good One Looks Like (WAGOLL)

๐Ÿ“
Save to Your Website Portfolio:

When you finish creating your project in your software, copy the share link or take a screenshot and publish it onto your student portfolio website!

Reflect

๐ŸŽฏ

Self-Assessment & Reflection

How many total possible shift keys exist in the 26-letter English alphabet?

๐ŸŸขSecure Level

Decrypts a message using a Caesar shift of -3 and handles wrap-around letters (e.g. 'Z' shifting forward to 'C').

Learning check

Learning Check

Using a Caesar Shift of +1, what does the word 'CAT' become when encrypted?

Solve the cipher:

Answer correctly to unlock the next level.

Correct! C (+1) = D, A (+1) = B, T (+1) = U. DBU!Remember: Shift each letter forward by 1 spot in the alphabet: C->D, A->B, T->U.
Teacher setup, curriculum links and progress descriptors

Spark support

Routine: Zoom In

Teacher notes: Facilitate the Zoom In routine for 2โ€“3 minutes. Encourage students to connect the prompt to Function (Mathematical shifts create predictable algorithmic patterns.).

Achievement pathway

  • Foundation: Counts forward 3 alphabet steps from 'A' to find 'D'.
  • Developing: Encrypts a word using a Caesar shift of +3.
  • Secure: Decrypts a message using a Caesar shift of -3 and handles wrap-around letters (e.g. 'Z' shifting forward to 'C').
  • Mastering: Calculates reverse shift keys and explains why small shift keys are vulnerable to brute-force cracking.

Curriculum links

Curriculum strand: Everyday Digital Skills & Computational Science

Outcome: CY.01.B.1.2 โ€” Apply numeric shift algorithms (Caesar Cipher) to encode and decode text.

PYP: Function ยท Mathematical shifts create predictable algorithmic patterns.

Learner profile: Thinker

Competency tags

  • caesar-cipher
  • shift-cipher
  • algorithms
  • math-patterns

Gate support

Accessibility alternative: Students may verbally explain or point to the correct answer for "Using a Caesar Shift of +1, what does the word 'CAT' become when encrypted?" with a teacher or teaching assistant.

Teacher override: allow

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Locked level

Level 3: Frequency Analysis & Code Cracking

Complete the previous learning check to unlock this next level.

Level 3

Frequency Analysis & Code Cracking

Use letter frequency statistics to crack simple substitution ciphers without a key.

Learning objective

Students will count letter occurrences in an encrypted text to identify the most common letter ('E') and crack the cipher.

Let's Go!

Step media

Learn

Codebreakers don't guess blindlyโ€”they use statistics! In English, the letter 'E' appears about 12% of the time, followed by 'T' and 'A'. If an encrypted message has the letter 'X' appearing dozens of times, 'X' is almost certainly 'E'! In computing, pattern analysis and data statistics reveal hidden structures. As you explore the interactive Cipher Wheel Simulator below, focus on how to use frequency analysis to deduce the shift key and decrypt an intercepted ciphertext without being given the key.

Interactive Simulator Sandbox
Cryptography Studio:Step 3 โ€ข Bronze Tier
๐Ÿ”
Step 1 โ€ข Bronze (Level 1): Secret Symbols - Matching Key Decoders

Match secret symbols and ancient runes against the substitution key to decode hidden letters and reveal the secret spy word.

In Progress
Interactive Cryptography Canvas
Caesar Shift: +3
CIPHERSHIFT: +0
---
๐Ÿงฎ Modulo 26 Shift Formula

Mathematical definition of the Caesar shift with alphabet wrap-around:

Encryption: $E_n(x) = (x + n) \pmod26$
Decryption: $D_n(x) = (x - n) \pmod26$
Where $x$ is the letter index (0 = A, 1 = B, ..., 25 = Z) and $n$ is the shift key.
๐Ÿ“Š Standard English Letter Frequencies

Expected distribution across 100,000 words in standard English corpora:

LetterFreq %LetterFreq %
E12.70%T9.06%
A8.17%O7.51%
I6.97%N6.75%
S6.33%H6.09%
R5.99%D4.25%
๐Ÿ”‘ Asymmetric RSA Key Pair Architecture

Mathematical foundation of public/private key trapdoor one-way functions:

Primes: $p, q$ (Large random secret prime numbers)
Modulus: $n = p \times q$ (Public component)
Public Key: $(e, n)$ โ€ข Private Key: $(d, n)$
Factoring $n$ back into $p$ and $q$ takes thousands of years for 2048-bit keys on classical computers.
โšก Cryptographic Hash Standard (NIST FIPS 180-4)
Algorithm:SHA-256 (Secure Hash Algorithm, 256-bit output)
Collision Resistance:$2^128$ operations required to find two different inputs with identical digests
Pre-image Resistance:Impossible to compute original text from digest ($2^256$ search space)

Apply Simulator Skills โ€ข Try it yourself

Be a Cryptanalyst

๐Ÿ”„Direct Simulator Transfer: Step 3 Tasks 7, 8 & 9

Now that you've practiced the virtual mechanics in the simulator above, apply those exact skills in your real computer environment:

๐ŸŒŸ Student Project GuideSuccess Criteria & WAGOLL (What A Good One Looks Like)โ–พ

๐ŸŽฏ Task Success Criteria (Rubric)

Foundation

Identifies that 'E' and 'T' are the most common letters in English books.

Developing

Tallies letter counts in a short encrypted paragraph to find the most frequent symbol.

Secure (Goal)

Uses frequency analysis to deduce the shift key and decrypt an intercepted ciphertext without being given the key.

Mastery

Explains why simple substitution ciphers are easily broken by computers using statistical analysis.

๐Ÿ‘€ What A Good One Looks Like (WAGOLL)

๐Ÿ“
Save to Your Website Portfolio:

When you finish creating your project in your software, copy the share link or take a screenshot and publish it onto your student portfolio website!

Reflect

๐ŸŽฏ

Self-Assessment & Reflection

Why does a longer encrypted message make frequency analysis easier than a 3-word message?

๐ŸŸขSecure Level

Uses frequency analysis to deduce the shift key and decrypt an intercepted ciphertext without being given the key.

Learning check

Learning Check

You intercepted a secret message where the letter 'Q' appears 25 times, far more than any other letter. What should you guess 'Q' represents?

Select the best codebreaking strategy:

Answer correctly to unlock the next level.

Bingo! Because 'E' is the most frequent English letter, the most frequent cipher symbol is usually 'E'.Think about letter statistics! 'E' is the most common letter in English.
Teacher setup, curriculum links and progress descriptors

Spark support

Routine: Parts, Purposes, Complexities

Teacher notes: Facilitate the Parts, Purposes, Complexities routine for 2โ€“3 minutes. Encourage students to connect the prompt to Connection (Pattern analysis and data statistics reveal hidden structures.).

Achievement pathway

  • Foundation: Identifies that 'E' and 'T' are the most common letters in English books.
  • Developing: Tallies letter counts in a short encrypted paragraph to find the most frequent symbol.
  • Secure: Uses frequency analysis to deduce the shift key and decrypt an intercepted ciphertext without being given the key.
  • Mastering: Explains why simple substitution ciphers are easily broken by computers using statistical analysis.

Curriculum links

Curriculum strand: Everyday Digital Skills & Computational Science

Outcome: CY.02.B.1.1 โ€” Use letter frequency statistics to crack simple substitution ciphers without a key.

PYP: Connection ยท Pattern analysis and data statistics reveal hidden structures.

Learner profile: Knowledgeable

Competency tags

  • frequency-analysis
  • cryptanalysis
  • pattern-recognition
  • statistics

Gate support

Accessibility alternative: Students may verbally explain or point to the correct answer for "You intercepted a secret message where the letter 'Q' appears 25 times, far more than any other letter. What should you guess 'Q' represents?" with a teacher or teaching assistant.

Teacher override: allow

Back to top

Locked level

Level 4: Symmetric vs Asymmetric Encryption

Complete the previous learning check to unlock this next level.

Level 4

Symmetric vs Asymmetric Encryption

Differentiate between single-key (symmetric) and dual-key (public/private key) encryption.

Learning objective

Students will demonstrate how public and private key pairs allow secure web communication without sharing secret passwords.

Let's Go!

Step media

Learn

Symmetric encryption uses ONE key to lock and unlock. But how do you share that key safely online? Asymmetric encryption solves this with TWO keys: a PUBLIC key (like an open padlock anyone can use to lock a box) and a PRIVATE key (the only key that unlocks it)!

Interactive Simulator Sandbox
Cryptography Studio:Step 4 โ€ข Bronze Tier
๐Ÿ”
Step 1 โ€ข Bronze (Level 1): Secret Symbols - Matching Key Decoders

Match secret symbols and ancient runes against the substitution key to decode hidden letters and reveal the secret spy word.

In Progress
Interactive Cryptography Canvas
Caesar Shift: +3
CIPHERSHIFT: +0
---
๐Ÿงฎ Modulo 26 Shift Formula

Mathematical definition of the Caesar shift with alphabet wrap-around:

Encryption: $E_n(x) = (x + n) \pmod26$
Decryption: $D_n(x) = (x - n) \pmod26$
Where $x$ is the letter index (0 = A, 1 = B, ..., 25 = Z) and $n$ is the shift key.
๐Ÿ“Š Standard English Letter Frequencies

Expected distribution across 100,000 words in standard English corpora:

LetterFreq %LetterFreq %
E12.70%T9.06%
A8.17%O7.51%
I6.97%N6.75%
S6.33%H6.09%
R5.99%D4.25%
๐Ÿ”‘ Asymmetric RSA Key Pair Architecture

Mathematical foundation of public/private key trapdoor one-way functions:

Primes: $p, q$ (Large random secret prime numbers)
Modulus: $n = p \times q$ (Public component)
Public Key: $(e, n)$ โ€ข Private Key: $(d, n)$
Factoring $n$ back into $p$ and $q$ takes thousands of years for 2048-bit keys on classical computers.
โšก Cryptographic Hash Standard (NIST FIPS 180-4)
Algorithm:SHA-256 (Secure Hash Algorithm, 256-bit output)
Collision Resistance:$2^128$ operations required to find two different inputs with identical digests
Pre-image Resistance:Impossible to compute original text from digest ($2^256$ search space)

Apply Simulator Skills โ€ข Try it yourself

Public Key Padlock Simulation

๐Ÿ”„Direct Simulator Transfer: Step 4 Tasks 10, 11 & 12

Now that you've practiced the virtual mechanics in the simulator above, apply those exact skills in your real computer environment:

๐ŸŒŸ Student Project GuideSuccess Criteria & WAGOLL (What A Good One Looks Like)โ–พ

๐ŸŽฏ Task Success Criteria (Rubric)

Foundation

States that websites use secret encryption to protect credit cards and passwords.

Developing

Explains the problem with symmetric keys: if you send the secret key over the internet, someone could intercept it.

Secure (Goal)

Role-plays Public/Private key exchange using the 'Padlock & Box' analogy (Public key = open padlock everyone can lock; Private key = secret key only you hold).

Mastery

Explains how HTTPS and SSL certificates use asymmetric encryption to establish secure internet connections.

๐Ÿ‘€ What A Good One Looks Like (WAGOLL)

๐Ÿ“
Save to Your Website Portfolio:

When you finish creating your project in your software, copy the share link or take a screenshot and publish it onto your student portfolio website!

Reflect

๐ŸŽฏ

Self-Assessment & Reflection

Why is it safe to share your Public Key with the whole world?

๐ŸŸขSecure Level

Role-plays Public/Private key exchange using the 'Padlock & Box' analogy (Public key = open padlock everyone can lock; Private key = secret key only you hold).

Learning check

Learning Check

In Public-Key (Asymmetric) Encryption, which key must you NEVER share with anyone?

Choose the correct key property:

Answer correctly to unlock the next level.

Spot on! Your Private Key must remain top secret because it is the only thing that can decrypt messages sent to you.Remember: Public keys can be shared with everyone, but Private keys must always be kept secret!
Teacher setup, curriculum links and progress descriptors

Spark support

Routine: What If...?

Teacher notes: Facilitate the What If...? routine for 2โ€“3 minutes. Encourage students to connect the prompt to Perspective (Secure global communication relies on mathematical key pairs.).

Achievement pathway

  • Foundation: States that websites use secret encryption to protect credit cards and passwords.
  • Developing: Explains the problem with symmetric keys: if you send the secret key over the internet, someone could intercept it.
  • Secure: Role-plays Public/Private key exchange using the 'Padlock & Box' analogy (Public key = open padlock everyone can lock; Private key = secret key only you hold).
  • Mastering: Explains how HTTPS and SSL certificates use asymmetric encryption to establish secure internet connections.

Curriculum links

Curriculum strand: Everyday Digital Skills & Computational Science

Outcome: CY.02.B.1.2 โ€” Differentiate between single-key (symmetric) and dual-key (public/private key) encryption.

PYP: Perspective ยท Secure global communication relies on mathematical key pairs.

Learner profile: Open-minded

Competency tags

  • symmetric-encryption
  • asymmetric-encryption
  • public-key
  • private-key

Gate support

Accessibility alternative: Students may verbally explain or point to the correct answer for "In Public-Key (Asymmetric) Encryption, which key must you NEVER share with anyone?" with a teacher or teaching assistant.

Teacher override: allow

Back to top

Locked level

Level 5: One-Way Hashing & Data Integrity

Complete the previous learning check to unlock this next level.

Level 5

One-Way Hashing & Data Integrity

Explain one-way cryptographic hash functions and their role in password storage and file integrity.

Learning objective

Students will demonstrate that a hash function creates a unique, fixed-length fingerprint that changes completely if even one character is altered.

Let's Go!

Step media

Learn

A Hash Function is like a digital blender! It takes any text or file and turns it into a unique string of characters (like `e3b0c442...`). It is a ONE-WAY process: you cannot reverse a hash back to the original text. Websites store password hashes so hackers can't read your real password!

Interactive Simulator Sandbox
Cryptography Studio:Step 5 โ€ข Bronze Tier
๐Ÿ”
Step 1 โ€ข Bronze (Level 1): Secret Symbols - Matching Key Decoders

Match secret symbols and ancient runes against the substitution key to decode hidden letters and reveal the secret spy word.

In Progress
Interactive Cryptography Canvas
Caesar Shift: +3
CIPHERSHIFT: +0
---
๐Ÿงฎ Modulo 26 Shift Formula

Mathematical definition of the Caesar shift with alphabet wrap-around:

Encryption: $E_n(x) = (x + n) \pmod26$
Decryption: $D_n(x) = (x - n) \pmod26$
Where $x$ is the letter index (0 = A, 1 = B, ..., 25 = Z) and $n$ is the shift key.
๐Ÿ“Š Standard English Letter Frequencies

Expected distribution across 100,000 words in standard English corpora:

LetterFreq %LetterFreq %
E12.70%T9.06%
A8.17%O7.51%
I6.97%N6.75%
S6.33%H6.09%
R5.99%D4.25%
๐Ÿ”‘ Asymmetric RSA Key Pair Architecture

Mathematical foundation of public/private key trapdoor one-way functions:

Primes: $p, q$ (Large random secret prime numbers)
Modulus: $n = p \times q$ (Public component)
Public Key: $(e, n)$ โ€ข Private Key: $(d, n)$
Factoring $n$ back into $p$ and $q$ takes thousands of years for 2048-bit keys on classical computers.
โšก Cryptographic Hash Standard (NIST FIPS 180-4)
Algorithm:SHA-256 (Secure Hash Algorithm, 256-bit output)
Collision Resistance:$2^128$ operations required to find two different inputs with identical digests
Pre-image Resistance:Impossible to compute original text from digest ($2^256$ search space)

Apply Simulator Skills โ€ข Try it yourself

Test the Avalanche Effect

๐Ÿ”„Direct Simulator Transfer: Step 5 Tasks 13, 14 & 15

Now that you've practiced the virtual mechanics in the simulator above, apply those exact skills in your real computer environment:

๐ŸŒŸ Student Project GuideSuccess Criteria & WAGOLL (What A Good One Looks Like)โ–พ

๐ŸŽฏ Task Success Criteria (Rubric)

Foundation

Understands that websites store passwords in a scrambled form rather than plain text.

Developing

Observed that changing 1 letter in an input produces a completely different hash output (Avalanche Effect).

Secure (Goal)

Explains why hashing is a 1-way function (easy to compute forward, impossible to reverse back into the password).

Mastery

Demonstrates how file checksums (hashes) verify if a downloaded file has been tampered with or corrupted.

๐Ÿ‘€ What A Good One Looks Like (WAGOLL)

๐Ÿ“
Save to Your Website Portfolio:

When you finish creating your project in your software, copy the share link or take a screenshot and publish it onto your student portfolio website!

Reflect

๐ŸŽฏ

Self-Assessment & Reflection

Why is it safer for a website to store your password hash instead of your actual password?

๐ŸŸขSecure Level

Explains why hashing is a 1-way function (easy to compute forward, impossible to reverse back into the password).

Learning check

Learning Check

What makes a cryptographic hash function different from normal encryption?

Select the correct feature of a hash:

Answer correctly to unlock the next level.

Correct! Hashes are one-way mathematical fingerprints. You cannot 'un-hash' them back to the original message.Think about it! Hashes are like smoothiesโ€”you can't un-blend them back to the original ingredients.
Teacher setup, curriculum links and progress descriptors

Spark support

Routine: See, Think, Wonder

Teacher notes: Facilitate the See, Think, Wonder routine for 2โ€“3 minutes. Encourage students to connect the prompt to Change (Irreversible digital signatures guarantee data authenticity and security.).

Achievement pathway

  • Foundation: Understands that websites store passwords in a scrambled form rather than plain text.
  • Developing: Observed that changing 1 letter in an input produces a completely different hash output (Avalanche Effect).
  • Secure: Explains why hashing is a 1-way function (easy to compute forward, impossible to reverse back into the password).
  • Mastering: Demonstrates how file checksums (hashes) verify if a downloaded file has been tampered with or corrupted.

Curriculum links

Curriculum strand: Everyday Digital Skills & Computational Science

Outcome: CY.03.B.1.1 โ€” Explain one-way cryptographic hash functions and their role in password storage and file integrity.

PYP: Change ยท Irreversible digital signatures guarantee data authenticity and security.

Learner profile: Principled

Competency tags

  • hashing
  • md5
  • sha256
  • data-integrity
  • digital-signatures

Gate support

Accessibility alternative: Students may verbally explain or point to the correct answer for "What makes a cryptographic hash function different from normal encryption?" with a teacher or teaching assistant.

Teacher override: allow

Back to top

Locked level

Level 6: Cybersecurity & Ciphers Audit

Complete the previous learning check to unlock this next level.

Level 6

Cybersecurity & Ciphers Audit

Evaluate real-world cryptographic applications (HTTPS, Wifi WPA3, Blockchain) and design a secure communication system.

Learning objective

Students will audit a simulated school network connection, identifying where encryption (HTTPS/WPA3) protects data in transit.

Let's Go!

Step media

Learn

Encryption is the invisible shield of the internet! Every time you see `https://` and a padlock in your browser, your connection is using SSL/TLS encryption. Without cryptography, online banking, private messaging, and secure voting would be impossible. In computing, robust security infrastructure protects human privacy and global systems. As you explore the interactive Cipher Wheel Simulator below, focus on how to construct a full security diagram mapping how data moves from user device -> Wi-Fi encryption -> HTTPS web server.

Interactive Simulator Sandbox
Cryptography Studio:Step 6 โ€ข Bronze Tier
๐Ÿ”
Step 1 โ€ข Bronze (Level 1): Secret Symbols - Matching Key Decoders

Match secret symbols and ancient runes against the substitution key to decode hidden letters and reveal the secret spy word.

In Progress
Interactive Cryptography Canvas
Caesar Shift: +3
CIPHERSHIFT: +0
---
๐Ÿงฎ Modulo 26 Shift Formula

Mathematical definition of the Caesar shift with alphabet wrap-around:

Encryption: $E_n(x) = (x + n) \pmod26$
Decryption: $D_n(x) = (x - n) \pmod26$
Where $x$ is the letter index (0 = A, 1 = B, ..., 25 = Z) and $n$ is the shift key.
๐Ÿ“Š Standard English Letter Frequencies

Expected distribution across 100,000 words in standard English corpora:

LetterFreq %LetterFreq %
E12.70%T9.06%
A8.17%O7.51%
I6.97%N6.75%
S6.33%H6.09%
R5.99%D4.25%
๐Ÿ”‘ Asymmetric RSA Key Pair Architecture

Mathematical foundation of public/private key trapdoor one-way functions:

Primes: $p, q$ (Large random secret prime numbers)
Modulus: $n = p \times q$ (Public component)
Public Key: $(e, n)$ โ€ข Private Key: $(d, n)$
Factoring $n$ back into $p$ and $q$ takes thousands of years for 2048-bit keys on classical computers.
โšก Cryptographic Hash Standard (NIST FIPS 180-4)
Algorithm:SHA-256 (Secure Hash Algorithm, 256-bit output)
Collision Resistance:$2^128$ operations required to find two different inputs with identical digests
Pre-image Resistance:Impossible to compute original text from digest ($2^256$ search space)

Apply Simulator Skills โ€ข Try it yourself

School Network Security Audit

๐Ÿ”„Direct Simulator Transfer: Step 6 Tasks 16, 17 & 18

Now that you've practiced the virtual mechanics in the simulator above, apply those exact skills in your real computer environment:

๐ŸŒŸ Student Project GuideSuccess Criteria & WAGOLL (What A Good One Looks Like)โ–พ

๐ŸŽฏ Task Success Criteria (Rubric)

Foundation

Locates the padlock icon in a browser address bar indicating HTTPS encryption.

Developing

Explains the risk of sending unencrypted data over public open Wi-Fi networks.

Secure (Goal)

Constructs a full security diagram mapping how data moves from user device -> Wi-Fi encryption -> HTTPS web server.

Mastery

Evaluates emerging cryptographic concepts (Quantum computing threats to encryption) and presents a security recommendation report.

๐Ÿ‘€ What A Good One Looks Like (WAGOLL)

๐Ÿ“
Save to Your Website Portfolio:

When you finish creating your project in your software, copy the share link or take a screenshot and publish it onto your student portfolio website!

Reflect

๐ŸŽฏ

Self-Assessment & Reflection

How would society be different if internet encryption was suddenly turned off?

๐ŸŸขSecure Level

Constructs a full security diagram mapping how data moves from user device -> Wi-Fi encryption -> HTTPS web server.

Learning check

Learning Check

What does the padlock icon next to a web address (HTTPS) tell you?

Choose the best security action:

Answer correctly to complete this strand.

Outstanding! The padlock means HTTPS encryption is actively scrambling your data during transit.Remember: The HTTPS padlock confirms that your connection is encrypted and secure.
Teacher setup, curriculum links and progress descriptors

Spark support

Routine: 3-2-1 Bridge

Teacher notes: Facilitate the 3-2-1 Bridge routine for 2โ€“3 minutes. Encourage students to connect the prompt to Responsibility (Robust security infrastructure protects human privacy and global systems.).

Achievement pathway

  • Foundation: Locates the padlock icon in a browser address bar indicating HTTPS encryption.
  • Developing: Explains the risk of sending unencrypted data over public open Wi-Fi networks.
  • Secure: Constructs a full security diagram mapping how data moves from user device -> Wi-Fi encryption -> HTTPS web server.
  • Mastering: Evaluates emerging cryptographic concepts (Quantum computing threats to encryption) and presents a security recommendation report.

Curriculum links

Curriculum strand: Everyday Digital Skills & Computational Science

Outcome: CY.03.B.1.2 โ€” Evaluate real-world cryptographic applications (HTTPS, Wifi WPA3, Blockchain) and design a secure communication system.

PYP: Responsibility ยท Robust security infrastructure protects human privacy and global systems.

Learner profile: Reflective

Competency tags

  • https
  • wifi-security
  • wpa3
  • blockchain
  • cryptography-audit

Gate support

Accessibility alternative: Students may verbally explain or point to the correct answer for "What does the padlock icon next to a web address (HTTPS) tell you?" with a teacher or teaching assistant.

Teacher override: allow

๐ŸŽ’ Students Home โ†’

Install App for Classroom

One-click fullscreen learning for Chromebooks, iPads & PCs

๐Ÿ–ฅ๏ธ
Distraction-FreeFullscreen window without browser tabs or search clutter.
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1-Tap LaunchPin directly to the Chromebook shelf, iPad dock, or Windows taskbar.
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Safe & Ad-Free100% free, private, and no app store logins or passwords needed.
  1. 1
    Click the Install button

    In your browser, look at the right end of the top web address bar for the ๐Ÿ’ป Install or โค“ icon.

  2. 2
    Confirm "Install"

    A popup will ask if you want to install "Ed Tech Hub". Click Install.

  3. 3
    Pin to your Shelf

    Right-click (or two-finger tap) the app icon in your Chromebook bottom shelf and select "Pin"!