For Engineers · RSA Encryption
RSA Encryption for a checksum
Built for engineers using it for real design work. Go from concept to a running model in the browser, then scale to the cloud when needed. Simulate a checksum live below — adjust the inputs and watch it respond, right in your browser.
RSA Public-Key EncryptionLive
the math behind secure internet
message
42
↓ encrypt: 42^3 mod 391
ciphertext
189
↓ decrypt: 189^235 mod 391
recovered
42
Controls
Presets
Prime p
Prime q
Message (number < n)
RSA rests on a one-way street: multiplying two big primes is easy, but factoring the product back apart is practically impossible. The public key (n, e) encrypts by raising the message to the power e mod n; only the private key d — computable only from the secret primes — can undo it. Real keys use 600-digit primes; these tiny ones just show the machinery.
Data Inspector
Modulus n = p·q391
φ(n)352
Public key e3
Private key d235
Governing equation
Reading this result: The public key (n=391, e=3) turns 42 into ciphertext 189; only the private key d=235, derived from the secret primes, brings it back to 42. With primes this small, n could be factored instantly — real RSA uses 600-digit primes.
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Frequently asked questions
- Is this good for engineers?
- Yes — this version of "RSA Encryption for a checksum" is framed for engineers using it for real design work. Go from concept to a running model in the browser, then scale to the cloud when needed.
- Do I need to install anything?
- No. It runs in any modern browser, free, with no account required.