Difference Between AES and RC4 (With Table)

Difference Between AES and RC4 (With Table)

Preserving our private information while we trade information over the Web is critical. Cryptographic techniques such as AES and RC4 are utilized to ensure data security. Cryptographers created this excellent method that is difficult for a cryptanalyst by mixing elements from mathematics and computer science.

AES vs RC4

The main difference between AES and RC4 is that they use separate ciphers. AES is blocking encryption that uses block sizes to encode plain text.  On the other hand, RC4 is a stream encryption algorithm that encrypts a bit at a time, similar to how a stream flows.

In response to imminent DES challenges, NIST started creating the Advanced Encryption Standard in 1997. The top encrypting competitor was picked from fifteen alternatives that participated in open tendering to meet AES criteria. AES employs a 128-bit component and 3 important lengths: 128, 192, and 256 bits.

Ron Rivest created the RC4 for the sake of Evading detection. It is an asymmetric encryption algorithm that encrypts plaintext by encoding it little by little with a key. Key lengths come in many sizes, between 64 and 128 bits. RC4 was initially kept from the public until its release to the public. Ron’s passcode is his other identity.

Comparison Table Between AES and RC4

MeaningThe Advanced Encryption Standard is a type of symmetric block encryption.
Rivest Cipher 4 is a symmetric stream cipher.
SourceIn 1997, an open contest was held to design AES.
In 1987, Ron Rivest created RC4.
SecurityAES is a much more secure algorithm than RC4.
RC4 is much less safe than AES.
Key lengths128, 192, and 256 bits64 or 128 bits
UsesSSL, TSL, etc.NASA, NIST, etc

What is AES?

AES, which stands for “Advanced Encryption Standard,” is a widely adopted symmetric encryption algorithm used for securing sensitive data and communications. It was established as a federal standard by the U.S. National Institute of Standards and Technology (NIST) in 2001, following a public competition to select a successor to the aging Data Encryption Standard (DES).

Key features of AES include:

  1. Symmetric Encryption: AES is a symmetric-key algorithm, meaning the same secret key is used for encryption and decryption. This simplicity makes it efficient for real-time encryption and decryption.
  2. Block Cipher: AES operates on fixed-size data blocks, 128 bits (16 bytes), and supports key lengths of 128, 192, or 256 bits. It encrypts data using a series of substitution and permutation operations known as rounds.
  3. Security: AES is considered highly secure when implemented correctly. It has withstood extensive cryptanalysis and is resistant to most known attacks. The key length (128, 192, or 256 bits) influences the level of security.
  4. Standardization: AES has become a global encryption standard, adopted by governments, organizations, and industries worldwide for securing data at rest, in transit, and in various applications.
  5. Versatility: AES is suitable for many applications, including secure communication protocols, data encryption, file and disk encryption, and more.
  6. Performance: AES is known for its efficiency and speed, making it a practical choice for encrypting large volumes of data in real time.

What is RC4?

RC4, short for “Rivest Cipher 4,” is a symmetric stream cipher algorithm developed by Ron Rivest in 1987. It gained significant popularity due to its simplicity, speed, and ease of implementation. RC4 is designed for encrypting and decrypting data in real-time, making it suitable for various applications like secure communications and data encryption.

Key features of RC4 include:

  1. Stream Cipher: RC4 is a stream cipher, meaning it generates a pseudorandom keystream of bits that are XORed with the plaintext to produce ciphertext. This makes it suitable for encrypting data of arbitrary length.
  2. Variable Key Length: RC4 supports variable key lengths, ranging from 40 to 2048 bits. The longer the key, the more secure the encryption.
  3. Initialization: The algorithm begins with an initial key setup phase to generate the internal state and a pseudorandom permutation of all possible bytes.
  4. Pseudorandom Keystream: RC4 generates a stream of pseudorandom bytes combined with the plaintext to produce ciphertext. The keystream is generated based on the internal state and the secret key.
  5. Speed: RC4 is known for its speed and efficiency, making it suitable for applications that require real-time encryption and decryption.

Main Differences Between AES and RC4

AES (Advanced Encryption Standard):

  • Symmetric Encryption: AES is a symmetric encryption algorithm, meaning the same key is used for both encryption and decryption.
  • Block Cipher: It operates on fixed-size blocks of data (128 bits) and supports key lengths of 128, 192, or 256 bits.
  • Standardized Algorithm: AES is a widely accepted and standardized encryption algorithm, chosen by the U.S. National Institute of Standards and Technology (NIST) as a replacement for the aging DES (Data Encryption Standard).
  • Security: AES is considered highly secure and resistant to attacks when used with a strong key and proper implementation.
  • Algorithm Structure: AES uses a substitution-permutation network (SPN) structure, involving multiple rounds of substitution and permutation operations.
  • Adoption: AES is commonly used in various security applications, including data encryption, VPNs, secure communication protocols, and more.
  • Key Expansion: AES employs a key expansion process to generate round keys from the initial encryption key.

RC4 (Rivest Cipher 4):

  • Stream Cipher: RC4 is a stream cipher that generates a pseudorandom stream of bits to be XORed with the plaintext for encryption or decryption.
  • Variable Key Length: RC4 supports variable key lengths, 40 to 2048 bits, making it more flexible in key selection.
  • Historical Significance: In early versions, RC4 was widely used for various applications, including SSL/TLS encryption.
  • Security Concerns: RC4 has been plagued by security vulnerabilities, leading to widespread deprecation and replacement with more secure ciphers.
  • Vulnerabilities: Weaknesses in the RC4 algorithm, such as biases in the initial keystream bytes, have made it susceptible to practical attacks.
  • Decreased Adoption: Due to security issues, RC4 is no longer considered secure and is discouraged for use in modern cryptographic applications.
  • Simplicity: RC4 is known for its simplicity and ease of implementation, but its vulnerabilities have led to its obsolescence.


  1. https://ieeexplore.ieee.org/abstract/document/1258477/
  2. https://asat.journals.ekb.eg/article_23497.html
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