RSA is a widely used public-key cryptosystem, named after its inventors Ron Rivest, Adi Shamir, and Leonard Adleman, who first publicly described the algorithm in 1977. It is one of the oldest and most influential asymmetric encryption algorithms and remains foundational in securing digital communications and transactions today.
RSA is based on the mathematical difficulty of factoring large integers, specifically the product of two large prime numbers. This difficulty underpins its security: while multiplying two large primes is computationally easy, reversing the process—determining the original primes from their product—is considered infeasible with current technology.
The RSA cryptosystem uses a pair of keys: Public Key: Used for encryption and digital signature verification. It consists of a modulus (the product of two large primes) and a public exponent. Private Key: Used for decryption and digital signature creation. It is mathematically linked to the public key but cannot be feasibly derived from it without factoring.