Async send sigma3

src/credentials/FabricTable.h

@@ -717,6 +717,14 @@ class DLL_EXPORT FabricTable
      */
     bool HasOperationalKeyForFabric(FabricIndex fabricIndex) const;
 
+    /**
+     * @brief Returns the operational keystore. This is used for
+     *        CASE and the only way the keystore should be used.
+     *
+     * @return The operational keystore, nullptr otherwise.
+     */
+    const Crypto::OperationalKeystore * GetOperationalKeystore() { return mOperationalKeystore; }
+
     /**
      * @brief Add a pending trusted root certificate for the next fabric created with `AddNewPendingFabric*` methods.
      *

src/crypto/OperationalKeystore.h

@@ -148,6 +148,19 @@ class OperationalKeystore
     virtual void RevertPendingKeypair() = 0;
 
     // ==== Primary operation required: signature
+    /**
+     * @brief Whether `SignWithOpKeypair` may be performed in the background.
+     *
+     * If true, `CASESession` may attempt to perform `SignWithOpKeypair` in the
+     * background. In this case, `OperationalKeystore` should protect itself,
+     * e.g. with a mutex, as the signing could occur at any time during session
+     * establishment.
+     *
+     * @retval true if `SignWithOpKeypair` may be performed in the background
+     * @retval false if `SignWithOpKeypair` may NOT be performed in the background
+     */
+    virtual bool SupportsSignWithOpKeypairInBackground() const { return false; }
+
     /**
      * @brief Sign a message with a fabric's currently-active operational keypair.
      *
@@ -164,7 +177,6 @@ class OperationalKeystore
      * @retval CHIP_ERROR_INVALID_FABRIC_INDEX if no active key is found for the given `fabricIndex` or if
      *                                         `fabricIndex` is invalid.
      * @retval other CHIP_ERROR value on internal crypto engine errors
-     *
      */
     virtual CHIP_ERROR SignWithOpKeypair(FabricIndex fabricIndex, const ByteSpan & message,
                                          Crypto::P256ECDSASignature & outSignature) const = 0;

src/lib/support/CHIPMem.h

@@ -193,6 +193,9 @@ inline SharedPtr<T> MakeShared(Args &&... args)
     return SharedPtr<T>(New<T>(std::forward<Args>(args)...), Deleter<T>());
 }
 
+template <typename T>
+using WeakPtr = std::weak_ptr<T>;
+
 // See MemoryDebugCheckPointer().
 extern bool MemoryInternalCheckPointer(const void * p, size_t min_size);