> For the complete documentation index, see [llms.txt](https://hinkal-team.gitbook.io/hinkal/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hinkal-team.gitbook.io/hinkal/technical-description/circuits.md).

# Circuits

Both Hinkal circuits— EVM and Solana—are built to support privacy‑preserving, multi‑token transactions in a UTXO‑style model. Hinkal treats each token deposit as a *commitment*, a cryptographic hash that conceals the amount, token address, stealth public key and timestamp. Spending a commitment requires revealing a *nullifier* (a hash of the commitment and a signature) that proves ownership without exposing the spender’s secret key or linking the spend to other transactions. The circuits allow a user to aggregate multiple inputs and produce multiple outputs across several ERC‑20 tokens, all within a single zero‑knowledge proof.