# HEADER_ALG

> `const` **HEADER\_ALG**: `1` = `1`

Defined in: [packages/filecoin-encryption-envelope/src/constants.ts:12](https://github.com/FilOzone/synapse-sdk/blob/4fe24ea1c76c9b1fa1489b7cdbb1cc279bd2576a/packages/filecoin-encryption-envelope/src/constants.ts#L12)

`alg`, RFC 9052 §3.1. Selects the encryption scheme, see the ALG_* constants.