how it works ⚛

entropy

Entropy is the measure of genuine surprise — how unpredictable the next thing is. Computers are deliberately built to have none of it: given the same input they produce the same output every time, which is exactly right for spreadsheets and exactly wrong for shuffling a deck. On its own, an algorithm can only fake it — pseudo-random numbers that look shuffled but are fully determined by where they started. To be truly unpredictable, a machine has to import surprise from the physical world: electrical noise, radioactive decay — or, here, the quantum jitter of empty space. That imported surprise is the ingredient that makes Tarot Friend possible: without real entropy there is no real draw, only a script pretending to shuffle. With it, nobody — not the server, not the reader, not anyone — can know which card is coming until it arrives.

the draw

Each pull uses two private quantum draws from ANU — one of 78 for the card, one of 2 for its orientation. 64 bytes of vacuum fluctuation, never reused.

The entropy comes from the Australian National University's quantum random number generator, which measures fluctuations of the vacuum — outcomes that quantum mechanics says are fundamentally unpredictable. The server keeps a pool of those bytes and every draw consumes 32 fresh ones, mapped to a card with unbiased rejection sampling (no modulo skew: every card is exactly as likely as every other).

the artwork

Card images are generated per draw, prompted to stay faithful to the composition and symbolism of the classic 1909 Rider-Waite-Smith deck, illustrated by Pamela Colman Smith. The quantum bytes of your draw seed each rendering, so no two drawings of the same card are ever identical — and reversed cards are simply the same upright card turned, as with a physical deck.

the reading

Readings are written by Claude in the voice of the friend you choose. The card's traditional meaning stays the same across every friend — only the delivery changes.