//! Shared trait for secret/seed storage backends.
//!
//! Both VTA (`SeedStore` — BIP-32 master seed) and VTC (`SecretStore` — raw key
//! material) use this trait. Service crates provide their own implementations
//! for AWS, GCP, Azure, OS keyring, etc.
use Future;
use Pin;
use crateAppError;
type BoxFuture<'a, T> = ;
/// Backend for storing and retrieving secret key material.
///
/// Implementations should encrypt at rest (AWS KMS, GCP KMS, Azure Key Vault)
/// or use OS-level protection (keyring). The plaintext file backend exists only
/// as a development fallback.