@effectstream/crypto

Multi-chain signature verification - one API that verifies wallet signatures from EVM, Cardano, Polkadot, Algorand, Mina, Midnight, and Solana. Also includes the Prando seeded RNG used for on-chain-derived randomness.

• Multi-chain signature verification: EVM, Cardano, Polkadot, Algorand, Mina, Midnight, Solana.
• Bundles the Prando seeded RNG for on-chain-derived randomness.
• Used by the batcher to verify user-submitted input signatures.
• Only depends on @effectstream/utils; safe to use standalone.

Install

bun add @effectstream/crypto
# or
npm install @effectstream/crypto

Standalone usage

Any TypeScript app that lets users sign in with a wallet can use CryptoManager to verify the signature server-side, without pulling in the rest of EffectStream.

import { CryptoManager } from "@effectstream/crypto";
import { AddressType } from "@effectstream/utils";

const evm = CryptoManager.getCryptoManager(AddressType.EVM);

const ok = await evm.verifySignature(
  "0xabcdefabcdefabcdefabcdefabcdefabcdefabcd",
  "Sign in to my dapp at 2026-05-14T00:00:00Z",
  "0x...the 130-hex-char signature...",
);

if (!ok) throw new Error("bad signature");

The same CryptoManager works for Cardano, Polkadot, Algorand, Mina, and Midnight signatures - switch the AddressType and pass the chain-native signature string.

Deterministic randomness with Prando

Prando is a seeded RNG you can drive from any deterministic source (block hash, transaction id, RNG-as-a-service result). Useful for on-chain games that need verifiable shuffles or dice rolls.

import { Prando } from "@effectstream/crypto";

const rng = new Prando(blockHash); // any string or number seed
const roll = rng.nextInt(1, 6);

// Re-seeding with the same value reproduces the same sequence.
const replay = new Prando(blockHash);
replay.nextInt(1, 6); // === roll

Inside EffectStream

@effectstream/crypto is what the batcher uses to verify user-submitted input signatures before accepting them into a batch, and what the state machine uses to derive randomness from on-chain hashes (generateEffectstreamBlockHash). It depends only on @effectstream/utils.

Key exports

• CryptoManager - chain-aware factory. CryptoManager.getCryptoManager(addressType) returns an IVerify. Per-chain accessors: CryptoManager.Evm(), .Cardano(), .Polkadot(), .Algorand(), .Mina(), .Midnight(), .Solana().
• IVerify - common interface: verifyAddress, verifySignature, decodeAddress.
• Prando - seeded deterministic RNG. next(), nextInt(lo, hi), nextString(n), reset().
• generateEffectstreamBlockHash - block-hash helper used by the EffectStream runtime.

Examples

Runnable examples: src/Prando.test.ts and test/examples.test.ts. Both run as part of bun test ./packages.

For end-to-end signature flows, see e2e/evm/sync/batcher.test.ts.

Links

• Docs: https://effectstream.github.io/docs/packages/sdk/crypto
• Source: https://github.com/effectstream/effectstream/tree/main/packages/effectstream-sdk/crypto