How do I simulate a one-time pad?

Open this page and use the live RSA Encryption tool below — set your inputs and the simulation runs instantly in your browser using real numerics. No install, no account needed.

Yes. The simulation runs free in your browser. A one-time unlock or a Pro plan adds advanced parameters, saved presets, data import, and clean exports.

Can I use my own numbers?

Absolutely — every input is adjustable, and with data import you can drive a one-time pad from your own measurements.

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RSA Encryption for a one-time pad

Simulate a one-time pad live in your browser. This runs the real RSA Encryption solver — adjust the inputs, watch it respond instantly, and export the result. No install, no account.

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RSA Public-Key EncryptionLive

the math behind secure internet

message

↓ encrypt: 42^3 mod 391

ciphertext

189

↓ decrypt: 189^235 mod 391

recovered

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.

▶ Run in Python

Data Inspector

Modulus n = p·q391

φ(n)352

Public key e3

Private key d235

Governing equation

n = pq = 17 \cdot 23 = 391, c = m^{e} mod n = 189, m = c^{d} mod n = 42

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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About this simulation

The full RSA Encryption tool models a one-time pad with the same numerics engineers and scientists use — running entirely client-side. Change any parameter and the result updates in real time, so you can build intuition, check a design, or teach the concept without spreadsheets or installs.

More you can do with RSA Encryption

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Other ways to simulate a one-time pad

Diffie-Hellman for a one-time pad Classical Ciphers for a one-time pad Hash Avalanche for a one-time pad Shannon Entropy for a one-time pad Huffman Coding for a one-time pad Hamming Code for a one-time pad

Frequently asked questions

How do I simulate a one-time pad?: Open this page and use the live RSA Encryption tool below — set your inputs and the simulation runs instantly in your browser using real numerics. No install, no account needed.
Is it free?: Yes. The simulation runs free in your browser. A one-time unlock or a Pro plan adds advanced parameters, saved presets, data import, and clean exports.
Can I use my own numbers?: Absolutely — every input is adjustable, and with data import you can drive a one-time pad from your own measurements.