package hostactors

import (
	"crypto/sha256"
	"encoding/hex"
)

// GroupBoxReference is the reference of a box its region's group launched
// (census ruling region-ha-2b): "g-" and the first 20 hex digits of
// sha256("carlos-box-ref-v1|" + account + "|" + instance). Status labels
// come from 1,600 values and collide as groups replace their boxes;
// instance ids never repeat in an account, and 80 bits of their digest
// make a collision negligible. It is a pseudonym, so the public status
// feed never shows an instance id. The box derives it to publish under it,
// and the console derives it again from the instance it proved (the
// attempt's, then the roster's pinned one) to read and admit it, never
// trusting the key a box chose. Boxes an operator enrolled keep their
// labels.
func GroupBoxReference(account, instance string) string {
	sum := sha256.Sum256([]byte("carlos-box-ref-v1|" + account + "|" + instance))
	return "g-" + hex.EncodeToString(sum[:])[:20]
}