Ruby: Add rb/weak-cryptographic-algorithm query

ruby/ql/src/queries/security/cwe-327/BrokenCryptoAlgorithm.ql

@@ -0,0 +1,20 @@
+/**
+ * @name Use of a broken or weak cryptographic algorithm
+ * @description Using broken or weak cryptographic algorithms can compromise security.
+ * @kind problem
+ * @problem.severity warning
+ * @security-severity 7.5
+ * @precision high
+ * @id rb/weak-cryptographic-algorithm
+ * @tags security
+ *       external/cwe/cwe-327
+ */
+
+import ruby
+import codeql.ruby.Concepts
+
+from Cryptography::CryptographicOperation operation
+where operation.isWeak()
+select operation,
+  "The cryptographic algorithm " + operation.getAlgorithm().getName() +
+    " is broken or weak, and should not be used."