Difference Between AES and RSA Encryption

Pre-requisites: AES, RSA

Encryption in cryptography is a process by which a plain text or a piece of information is converted into cipher text or a text which can only be decoded by the receiver for whom the information was intended. 

Advanced Encryption Standard (AES)

AES, a symmetric key encryption method developed by Belgian cryptographers Joan Daemen and Vincent Rijmen, was presented by NIST in 2001. Rijndael secures critical data in communication networks, financial transactions, and file storage. AES supports 128-bit data blocks and 128, 192, or 256-bit keys. Substitutions, permutations, and mixing are used to secure encryption. The transmitter and receiver share a key for symmetric encryption. Alice and Bob must securely exchange a secret key before sending an AES-encrypted message. Bob can decrypt the message using the same secret key.

Rivest-Shamir-Adleman (RSA)

Ron Rivest, Adi Shamir, and Leonard Adleman invented RSA in 1977. This encryption uses huge prime numbers and the difficulty of factoring large composite numbers. RSA encrypts and decrypts using public and private keys. The public key is disclosed, but the secret key is concealed. This enables keyless secure communication. Bob’s public key lets Alice send Bob an RSA-encrypted message. Bob’s private key decrypts the message. Digital signatures and key exchange use RSA. RSA is slower than AES and unsuitable for big data encryption owing to its computational complexity.

Difference Between AES and RSA Encryption

Attribute	AES	RSA
Type	Symmetric key encryption	Asymmetric (public key) encryption
Key Length	128, 192, or 256 bits	1024, 2048, or 4096 bits (common)
Speed & Efficiency	Fast and efficient for bulk data	Slower, not suited for large data
Use Cases	Encrypting files, databases, and channels	Key exchange, authentication, signatures
Encryption Process	Substitution-permutation network	Modular exponentiation
Key Distribution	Requires a secure method to share the secret key	No need to securely share the public key
Computational Complexity	Relatively low	High, especially for large key lengths
Attack Resistance	Vulnerable to brute-force attacks, but still secure	Vulnerable to advances in factoring techniques
Key Management	Easier, as only one key is involved	More complex due to separate public and private keys
Suitability for Hardware	Well-suited for hardware implementation	Hardware implementation can be more challenging
Quantum Resistance	Vulnerable to quantum attacks (e.g., Grover’s algorithm)	Potentially vulnerable to quantum attacks
Example	Secure file storage and communication	Secure email and digital certificates