Initial QSfera import

Server/vendor/github.com/pjbgf/sha1cd/detection.go

@@ -0,0 +1,11 @@
+package sha1cd
+
+import "hash"
+
+type CollisionResistantHash interface {
+	// CollisionResistantSum extends on Sum by returning an additional boolean
+	// which indicates whether a collision was found during the hashing process.
+	CollisionResistantSum(b []byte) ([]byte, bool)
+
+	hash.Hash
+}