定义 KeyStore 接口,存储秘钥。
type KeyStore interface {
// ReadOnly returns true if this KeyStore is read only, false otherwise.
// If ReadOnly is true then StoreKey will fail.
ReadOnly() bool
// GetKey returns a key object whose SKI is the one passed.
GetKey(ski []byte) (k Key, err error)
// StoreKey stores the key k in this KeyStore.
// If this KeyStore is read only then the method will fail.
StoreKey(k Key) (err error)
}