Struct Envelope 

pub struct Envelope {
    pub v: u8,
    pub data: Value,
    pub memo: Memo,
    pub checksum: String,
    pub kid: Option<u8>,
}

Fields

v: u8

data: Value

memo: Memo

checksum: String

kid: Option<u8>

Key ID used to sign this envelope. Lets the server hold multiple keys at once and verify each snapshot under the key it was signed with — the building block for zero-reload APP_KEY rotation.

Set from APP_KEYS="1:key1,2:key2" env on encode. Verifier looks up the matching key by kid and falls back to the default (single-key) path when the field is missing — back-compat with snapshots issued before this change.

Implementations

impl Envelope

pub fn build(app_key: &str, data: Value, memo: Memo) -> Self

Build a fresh envelope from state + memo, signing under the default key. Use build_with_kid when you need to control which key signs.

pub fn build_with_kid(kid: u8, app_key: &str, data: Value, memo: Memo) -> Self

Build a fresh envelope, signing under the named key and stamping kid into the envelope so the verifier can pick the same key out of the rotation set.

pub fn verify(&self, app_key: &str) -> Result<()>

Verify against a single key. Convenient when no rotation is in play. verify_with_keys is the multi-key form for rotation windows.

pub fn verify_with_keys(&self, keys: &[(u8, &str)]) -> Result<()>

Verify under a keyring — the rotation-aware path.

Resolution:

1. If self.kid is set, look up that key. If missing, the envelope was signed with a key the server no longer holds → tampered.
2. If self.kid is None, fall back to the default key (the first entry) — back-compat with snapshots from before kid existed.

keys is (kid, key) pairs in priority order; the encoder always uses the first entry to sign new envelopes.

Trait Implementations

impl Clone for Envelope

fn clone(&self) -> Envelope

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Envelope

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Envelope

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for Envelope

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.