Pedersen Commitment

A Pedersen commitment lets you commit to a value v with a random blinding r such that:

Hiding: the commitment reveals nothing about v.
Binding: you cannot later open it to a different value.
Homomorphic: commit(a) · commit(b) = commit(a + b).

commit(v, r) = g^v · h^r mod p

v r g h p

Result

—

Try it

Same (v, r) always gives the same commitment — try clicking twice.
Change r while keeping v the same — commitment changes (hiding).
Change v while keeping r the same — commitment changes (binding).

What's happening

The button calls a Rust function compiled to WebAssembly. The same commit function is used by the rollup server to lock account state. Read Ex1 for the full math and security argument.