In this lesson,
we will learn about symmetric cryptography.
Symmetric cryptography is a type of encryption
where the same key is used for both encrypting
and decrypting data.
Symmetric cryptography concepts include techniques
such as one-time pad and Lightweight Cryptography.
Symmetric cryptography is widely used
for its efficiency in securing data quickly and in bulk.
Usually, it uses algorithms
such as the Advanced Encryption Standard (AES).
Techniques, such as the One-time Pad,
may offer theoretically unbreakable encryption.
Lightweight Cryptography, on the other hand, is designed
for environments with limited power
and cryptographic processing resources, such as IoT
or Internet of Things devices.
Let's learn more about Symmetric Cryptography, Pne-time Pad,
and Lightweight Cryptography.
First, we have Symmetric Cryptography.
Symmetric cryptography is an encryption method
that uses the same key for both encrypting
and decrypting data.
The core advantage of symmetric cryptography is its ability
to handle bulk encryption efficiently, making it suitable
for secure file storage and network communications.
Common symmetric algorithms include
AES, DES, 3DES, Blowfish, Twofish, RC4, and ChaCha20.
The Advanced Encryption Standard, or AES,
is popular for its strong security and fast processing.
Also, it can function as both a block cipher
and a stream cipher.
The Data Encryption Standard, or DES,
is an older encryption algorithm with a 56-bit key.
DES is now considered insecure due to its vulnerability
to brute force attacks.
DES's enhanced version, Triple DES, or 3DES,
applies the DES encryption algorithms
three times to provide added security,
but it's a little bit slower.
Next, Blowfish is known for its speed
and adaptability with variable key lengths,
but Blowfish has been largely replaced
by its successor, Twofish, which offers enhanced security
and performance with up to 256-bit key lengths.
Finally, Rivest Cipher 4, or RC4, is a fast stream cipher,
but it's now outdated due to security flaws,
with ChaCha20 providing a secure
and efficient alternative to RC4.
ChaCha20 is widely used in internet protocols
for its robust encryption strength.
Second, we have One-time Pad.
The One-time Pad is considered one of the strongest forms
of symmetric encryption because it can provide
perfect forward secrecy when used correctly.
The core idea behind the one-time pad
is to use a completely random key
that is the exact same length
as the message being encrypted.
Each bit of the message is combined
with the corresponding bit of the key,
using a simple operation, like Exclusive-OR, or XOR,
which results in a completely random cipher text.
Because the key is as long as the message
and is truly random, there are no patterns
that can be exploited,
making the encrypted message theoretically unbreakable.
The key to one-time pad security
is that the random key must never be reused.
If the same key is used more than once,
patterns could emerge that would allow someone
to decrypt the message.
Additionally, the randomness of the key must be perfect.
Any predictable or repeated patterns in the key
would weaken the encryption.
So the major challenge with one-time pads
is then securely sharing the key between the sender
and receiver, especially since the key must be as long
as the message and only used once.
This makes distributing keys securely
and keeping them secret, a significant logistical problem.
This requirement makes one-time pads impractical
for everyday use, limiting them
to extremely sensitive communications, such as diplomatic
or military messages where maximum security is required.
Third and last, we have Lightweight Cryptography.
Lightweight Cryptography is specifically designed
for environments with limited computational resources,
such as Internet of Things or IOT devices, smart sensors,
and embedded systems.
Unlike traditional cryptographic algorithms like AES,
which are highly secure,
but can be computationally intensive,
Lightweight Cryptography is optimized to provide security
with minimal resource consumption.
This is achieved by using simpler
and smaller operations, reducing the algorithm's complexity,
while still maintaining an adequate level of security.
So, Lightweight Cryptography typically uses smaller keys,
reduced rounds of encryption,
and simpler mathematical operations
to keep computational demands low.
For instance, instead of the complex substitution
and permutation operations used in AES,
lightweight cryptographic algorithms might use
a basic bit manipulation techniques that require
less processing power and memory.
Additionally, these algorithms often have
shorter block sizes, which means they handle smaller chunks
of data at a time, further reducing the strain
on the device's processor.
While Lightweight Cryptography may not provide
the same level of security as more robust algorithms,
it offers a practical solution that protects data,
while allowing low-power devices
to operate effectively and securely.
So remember, symmetric cryptography uses the same key
for both encryption and decryption, making it efficient
for securing data quickly and in bulk.
Common symmetric algorithms include
the Advanced Encryption Standard, or AES,
the Data Encryption Standard, or DES, Triple DES, Blowfish,
Twofish, Rivest Cipher 4, or RC4,
and ChaCha20, each with varying levels
of security and performance.
Next, the one-time pad
is a unique symmetric encryption method that uses
a random key as long as the message itself,
offering a theoretically unbreakable encryption,
as long as the key is never reused and is truly random.
However, the challenges of managing
and securely sharing one-time pad keys make it impractical
for everyday use.
Last, Lightweight Cryptography is designed for devices
with limited computational power, such as Internet of Things
or IOT devices, balancing security
with minimal resource consumption
to protect data without overwhelming the device.