← ACARA Digital Technologies Years 9–10

Base64 is encoding, not encryption

Rewrites data using 64 printable characters so it can be sent as text. It has no secret key, so anyone can reverse it. It is encoding, not encryption, and protects nothing.

Part of: ACARA Digital Technologies Years 9–10 — Cyber Security Threats and Vulnerabilities — Module 129, QCE Digital Solutions Unit 4 — Digital Methods for Exchanging Data — Module 36, WA Computer Science ATAR Year 11 — Cyber Security — Module 72

Understanding Base64 is encoding, not encryption in ACARA Digital Technologies Years 9–10

What it does: These 64 printable characters (with = for padding) make up the Base64 alphabet, which is why the output is safe to send as text. Both are just different ways to write the same data and neither uses a key. Base64 packs more bits per character, so its output is shorter than hex. Base64 is encoding. It changes how data is written so it can travel as text. It does not use a secret key to protect anything. Base64 uses a public, well-known method. Free tools and a line of code can decode it, so there is no key to keep secret.

Common mistakes: The Python module is called base64, not base46. The first line should be import base64 so b64encode() can be used. Base64 is encoding, not encryption, so there is no decrypt function and no key. Anyone can reverse it with base64.b64decode(enc).

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This module's key terms are also in a printable crossword (Modules 876–944) and word search (Modules 860–944).

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Learning

Duo

Base64 turns the text "Hi" into "SGk=". Which statement describes what Base64 is?

Encryption: it hides data using a secret keyEncoding: it rewrites data in a different form

Matches

secret = base64.b64encode(password) # now it is safe

↓

Treating Base64 as encryption. There is no key, so anyone can decode it and read the password.

Applying

Meanings

Term

Base64

Meaning

Rewrites data using 64 printable characters so it can be sent as text. It has no secret key, so anyone can reverse it. It is encoding, not encryption, and protects nothing.

Practice

import base64

Testing

Gaps

import

Check Answer

Spots

1import base46

2msg = b'Hi'

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Quick Questions

1. Base64 turns the text "Hi" into "SGk=". Which statement describes what Base64 is?

A. Encoding: it rewrites data in a different form ✓

B. Encryption: it hides data using a secret key

Base64 is encoding. It changes how data is written so it can travel as text. It does not use a secret key to protect anything.

2. Mia finds the text "cGFzc3dvcmQ=" in a file. Who can turn it back into the original text?

A. Anyone, because Base64 has no secret key ✓

B. Only someone who knows the secret key

Base64 uses a public, well-known method. Free tools and a line of code can decode it, so there is no key to keep secret.

3. A developer stores user passwords as Base64 text. Is this a safe way to protect them?

A. Yes, the characters look scrambled so they are protected

B. No, anyone can decode Base64 straight away ✓

Looking scrambled is not the same as being protected. Base64 only changes the format. Passwords should be hashed with a salt instead.

4. Why is Base64 often used when sending files or images inside emails and web pages?

A. It locks the data so interceptors cannot read it

B. It rewrites data as printable text characters that can be sent as text ✓

Base64 uses 64 printable characters (A-Z, a-z, 0-9, + and /) so binary data can travel through systems built for text. Secrecy is not its job.

5. Which comparison of Base64 and hexadecimal (hex) is correct?

A. Both are encodings that anyone can reverse without a key ✓

B. Base64 is an encoding but hex is a secure encryption

Hex uses 16 characters and Base64 uses 64, but both just rewrite data. Neither uses a secret key, so neither protects data.

Match the Pairs

base64.b64encode(b"Hi") → Rewrites the bytes of Hi as Base64 text (SGk=). No key is used, so anyone can turn it back.

base64.b64decode("SGk=") → Reverses Base64 text back to the original data (Hi) with no password or key needed.

Base64 uses only 64 printable characters, so binary data can travel as plain text. → A-Z a-z 0-9 + /

Hex uses 16 characters for each 4 bits, while Base64 uses 64 characters for each 6 bits, so Base64 is shorter. → Hi = 4869 (hex) or SGk= (Base64)

secret = base64.b64encode(password) # now it is safe → Treating Base64 as encryption. There is no key, so anyone can decode it and read the password.

Encrypted with Base64: SGVsbG8= (only I can read it) → Base64 is not encrypted and has no secret key. Anyone can decode SGVsbG8= to Hello.

Key Term

Base64

Rewrites data using 64 printable characters so it can be sent as text. It has no secret key, so anyone can reverse it. It is encoding, not encryption, and protects nothing.

Fill in the Blanks

1. import base64 msg = b"Hi" print(base64.b64encode(msg))

Hint: Type the name of the Python library imported to work with this encoding.

2. import base64 coded = base64.b64encode(b"Hello") print(coded)

Hint: Type the function that turns bytes into Base64 text.

3. import base64 coded = "SGk=" print(base64.b64decode(coded))

Hint: Type the function that reverses Base64. It needs no key.

4. text = "SGk=" data = base64.b64decode(text) print(data)

Hint: Type the variable that holds the Base64 string. Notice that no secret key is passed in.

5. data = b"Hi" print(data.hex()) print(base64.b64encode(data))

Hint: Type the method that writes bytes in hexadecimal so you can compare it with Base64.

Spot the Error

Question 1

A import base46

B msg = b'Hi'

C code = base64.b64encode(msg)

D print(code)

Line A — The Python module is called base64, not base46. The first line should be import base64 so b64encode() can be used.

Question 2

A import base64

B pw = b'password1'

C enc = base64.b64encode(pw)

D print(base64.decrypt(enc))

Line D — Base64 is encoding, not encryption, so there is no decrypt function and no key. Anyone can reverse it with base64.b64decode(enc).

Question 3

A import base64

B enc = 'SGk='

C raw = base64.b64encode(enc)

D print(raw)

Line C — To get the original data back you must decode, not encode again. Line 3 should be raw = base64.b64decode(enc), which needs no key.

Question 4

A import base64

B data = b'Hi'

C print(data.hexdigest())

D print(base64.b64encode(data))

Line C — Bytes have a .hex() method that writes them in hex (16 characters). hexdigest() belongs to hash objects, not bytes. Line 3 should be print(data.hex()).

Question 5

A import base64

B def encode(text, key):

C b = text.encode()

D return base64.b64encode(b)

Line B — Base64 has no secret key, so the function needs no key parameter. The line should be def encode(text):.

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