I tried to explain what RC4 is in comic strips.
I explained what RC4 is and how you can break RC4.
RC4 or Rivest’s Cipher 4 was designed in 1987. It was a proprietary algorithm from RSA Security until it was reverse engineered and released into the public in 1994. Despite lacking academic peer-review, the simplistic and efficient design helped the public to massive adoption of such an algorithm until a security flaw was discovered in 2005.
What is the Logic Behind RC4
The logic behind RC4 is to randomly generate numbers to disguise secret messages and rearrange the way that no one can recognize them. When one wants to decrypt the secret code, the procedure then can reverse to reveal the secret messages.
Two Components of RC4
There are two distinct algorithms in RC4: Key Setup Algorithm (KSA) and Pseudo-random Generation Algorithm (PRGA).
Key Setup Algorithm (KSA) is an initial stage to generate array S. It is an initial stage to set up an initial key position and to replace the secret key for the next stage.
Pseudo-random Generation Algorithm (PRGA) is a process to get a keystream that is a key-value bridge between encryption and decryption.
Encryption and Decryption Procedure
The process of encryption involves:
- The user inputs a plain text file and a secret key
- The algorithm generates the keystream
- The keystream will pair with plain text and hide the information through new series of digits as an encrypted text
- The encrypted text is sent to the intended receiver and the receiver will decrypt the text and reveal the plain text
The process of decryption involves:
- Using the algorithm to inverse value from encrypted text and keystream
You can see the process is straightforward and efficient.
Advantages and Disadvantages
RC4’s advantages are simple to use and implement efficient performance and can handle large streams of data. The disadvantage of RC4 is that it is relatively easy to break in under an hour.
How to Break into RC4
The problem with RC4 is that the algorithm only repositioned the digit array location without changing its value. It is possible to guess the initial value if you know the initial position of the array. The NOMORE attack in 2015 demonstrated how easily RC4 can be cracked so long as attackers receive the initial value of RC4 through injecting code.
RC4 is an efficient algorithm to protect security with a simple and interactive process. It offers such technology available to advance and create a more secure network in the future.
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