Replication targets, remote tiers and on-demand migration sources each store a
remote secret in clear text under .rustfs.sys today. Record one design for all
three before any of them invents its own: seal only the secret fields, into an
added field so an old reader finds the credential absent rather than a
ciphertext it would sign with, unseal at remote-client construction, and reach
KMS through an installed hook because ECStore does not depend on rustfs-kms.
Covers the envelope format and its encryption context, the mixed-version
compatibility matrix, the rollout gate, rotation ownership and the fail-closed
rules.
Zhengchao An