# HEADER_KID

> `const` **HEADER\_KID**: `4` = `4`

Defined in: [packages/filecoin-encryption-envelope/src/cose/constants.ts:28](https://github.com/FilOzone/synapse-sdk/blob/bc8a4b093324ccef9b407251fcf4e91823c6f599/packages/filecoin-encryption-envelope/src/cose/constants.ts#L28)

`kid`, RFC 9052 §3.1. Recipients only; a byte string. Never a content header in this profile.