STEM
PrimeDojo
Multiply two primes: easy. Un-multiply their product: nearly impossible. That one gap is why your bank is safe. PrimeDojo walks you from clock arithmetic to a working RSA key you build, encrypt with, decrypt with — and then BREAK by factoring, all by hand and all on your device. Predict each step, then watch the maths. Ages 15–18.
#2b8a8a Distributed-narrative cast
Meet the cast
PrimeDojo is text-forward (R-OLDER-TEEN-DN-ADAPTED, ages 15–18) — no illustrated cast; the 'characters' are the pieces of an RSA key whose relationship IS the security. The modulus n = p·q is public, and its two prime factors are the whole secret. Euler's φ(n) = (p−1)(q−1) is the size of the clock the keys live on — computable only if you know p and q. The public exponent e locks a message (raise it to e); the private exponent d = e⁻¹ mod φ unlocks it (raise it to d). An attacker who could factor n would rebuild φ and then your d — so RSA is safe exactly when n is too big to factor. Every value is exact integer arithmetic computed on-device (mod, modpow, modinv, factor). Illustrated portraits/chapters/audio are N/A for the older-teen band, not a follow-on.
The modulus n = p·q
The public modulus — the product of two secret primes; its two prime factors are the entire secret of the key
Euler's φ(n)
The size of the clock the keys live on, (p−1)(q−1); computable only if you know p and q — which is why factoring n breaks everything
The public exponent e
Any number coprime to φ; encrypting is raising the message to the power e on the clock of size n — anyone can do it
The private exponent d
The modular inverse of e (d = e⁻¹ mod φ); it undoes encryption, and an attacker can find it only by first factoring n
What's inside
Learning goal
Multiply two primes: easy. Un-multiply their product: nearly impossible. That one gap is why your bank is safe. PrimeDojo walks you from clock arithmetic to a working RSA key you build, encrypt with, decrypt with — and then BREAK by factoring, all by hand and all on your device. Predict each step, then watch the maths. Ages 15–18.
Question kits
16 curriculum-aligned kits × 25 questions = 400 questions per app, mapped to recognized standards.
On-device AI mentor
FoundationModels-powered hints, feedback, and adaptive difficulty — all running locally.
How PrimeDojo handles your kid's data
- ✅ All progress, settings, and AI-generated content stays on the device
- ✅ No analytics, no tracking, no third-party SDKs
- ✅ No ads, no in-app purchases — you pay once
- ✅ COPPA compliant under the 2026 FTC amendments
- ✅ Parental controls + session limits + content filters built in
PrimeDojo runs on ForgeKit — the open-source Swift Package Manager framework that powers every Spark & Anvil app. ForgeKit ensures consistent accessibility, COPPA compliance, and design language across the portfolio, so your kid's progress and preferences feel coherent across every app they touch.
Coming to the App Store
PrimeDojo is in active development. Email us to hear when it ships — no marketing, no spam, just a one-shot launch announcement.
Email me at launch