Struct SealParams 

pub struct SealParams<'a> {

    pub sender_sk: &'a SecretKey,
    pub sender: Bytes32,
    pub sender_epoch: u32,
    pub recipient: Bytes32,
    pub recipient_pub: &'a [u8; 48],
    pub message_type: u32,
    pub shape: InteractionShape,
    pub correlation_id: Bytes32,
    pub stream: Option<StreamHeader>,
    pub counter: u64,
    pub timestamp_ms: u64,
    pub expires_at: u64,
    pub payload: &'a [u8],
}

Everything the sender supplies to seal one message (SPEC §5.1). The anti-replay counter + timestamp_ms and the expires_at TTL are sender-chosen; the crate binds + enforces them.

Fields

sender_sk: &'a SecretKey

The sender identity secret key (the ONE BLS12-381 key — signs G2 and does the static G1 DH).

sender: Bytes32

The sender DID launcher id (cleartext header, bound as AAD).

sender_epoch: u32

The sender key epoch for rotation disambiguation (SPEC §2 field 7).

recipient: Bytes32

The recipient DID launcher id.

recipient_pub: &'a [u8; 48]

The recipient BLS G1 identity public key (48-byte compressed), the seal target.

message_type: u32

The message type id (SPEC §4).

shape: InteractionShape

The interaction shape (SPEC §3).

correlation_id: Bytes32

The correlation id (SPEC §2 field 4).

stream: Option<StreamHeader>

The stream header, present iff shape is a stream frame (SPEC §3).

counter: u64

The per-(sender→recipient) strictly-monotonic anti-replay counter (SPEC §5.6).

timestamp_ms: u64

Sender wall-clock Unix milliseconds — the freshness field (SPEC §5.6).

expires_at: u64

Sender-controlled TTL, Unix milliseconds; 0 = no explicit expiry (SPEC §5.6b).

payload: &'a [u8]

The raw (uncompressed, unsealed) type-payload bytes.