I built a public RSA challenge using the original RSA Factoring Challenge numbers

This is a small cryptography experiment I’ve been working on.

I took the original RSA Factoring Challenge numbers (from the 1990s) and encrypted short messages with them using a fixed public exponent.

Each challenge provides:

\- the RSA modulus (n)

\- the public exponent (e)

\- the ciphertext (c)

The plaintext is never shown.

Instead, solutions are verified using a SHA-256 hash of the correct plaintext.

Some moduli are already factored historically, some are solvable today, and some remain unfactored — that difficulty curve is intentional and mirrors real cryptographic history.

This is \*\*not a CTF with artificial weaknesses\*\* and there are no trick keys.

The goal is to explore RSA exactly as it was originally challenged.

Site: https://rsa-challenge-site.onrender.com

I’d love feedback from people who’ve worked with RSA beyond toy examples.