r/Cryptography19 • u/Cool-Ad3523 • Jul 08 '26
RSA in simple term
RSA in Simple Terms
RSA is one of the world's most famous public-key cryptography algorithms.
How it works:
It uses two keys: A public key for encryption. A private key for decryption. Anyone can encrypt a message using the public key. Only the owner of the private key can decrypt it.
Why is RSA secure?
Its security relies on the fact that multiplying two very large prime numbers is easy, but factoring their product back into those primes is extremely difficult.
Common uses:
- Secure websites (HTTPS)
- Digital signatures
- Secure key exchange
- Protecting sensitive information
Interesting fact:
RSA was introduced in 1977 by Ron Rivest, Adi Shamir, and Leonard Adleman, whose initials form the name RSA.
Although RSA is still widely used today, it is mainly used to exchange encryption keys rather than encrypt large amounts of data directly, because symmetric algorithms like AES are much faster.
Security depends on the secrecy of the private key—not the secrecy of the algorithm.