pub fn encryption_keypair(
topic_id: &TopicId,
secret_rotation_function: &RotationHandle,
initial_secret_hash: [u8; 32],
unix_minute: u64,
) -> SigningKeypub fn encryption_keypair(
topic_id: &TopicId,
secret_rotation_function: &RotationHandle,
initial_secret_hash: [u8; 32],
unix_minute: u64,
) -> SigningKey