[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › [Crypto](https://evolu.dev/docs/api-reference/common/Crypto) › Entropy20

```ts
type Entropy20 = Uint8Array<ArrayBufferLike> &
  import("./Brand.ts").Brand<"Entropy"> &
  import("./Brand.ts").Brand<"Length20">;
```

Defined in: [packages/common/src/Crypto.ts:111](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/common/src/Crypto.ts#L111)

Cryptographic entropy of exactly 20 bytes.