* nix-store --import': import an archive created by nix-store

--export' into the Nix store, and optionally check the cryptographic
  signatures against /nix/etc/nix/signing-key.pub.  (TODO: verify
  against a set of public keys.)

src/libstore/store-api.hh

@@ -99,6 +99,10 @@ public:
     virtual void exportPath(const Path & path, bool sign,
         Sink & sink) = 0;
 
+    /* Import a NAR dump created by exportPath() into the Nix
+       store. */
+    virtual Path importPath(bool requireSignature, Source & source) = 0;
+
     /* Ensure that the output paths of the derivation are valid.  If
        they are already valid, this is a no-op.  Otherwise, validity
        can be reached in two ways.  First, if the output paths have