Add EC to secure algorithm whitelist for Java CWE-327 query

java/ql/lib/change-notes/2026-03-27-add-ec-to-secure-algorithms.md

@@ -0,0 +1,5 @@
+---
+category: minorAnalysis
+---
+* The `java/potentially-weak-cryptographic-algorithm` query no longer flags Elliptic Curve algorithms (`EC`, `ECDSA`, `ECDH`, `EdDSA`, `Ed25519`, `Ed448`, `XDH`, `X25519`, `X448`), HMAC-based algorithms (`HMACSHA1`, `HMACSHA256`, `HMACSHA384`, `HMACSHA512`), or PBKDF2 key derivation as potentially insecure. These are modern, secure algorithms recommended by NIST and other standards bodies. Previously, these algorithms were not included in the secure algorithm whitelist, causing false positives when using standard Java cryptographic APIs such as `KeyPairGenerator.getInstance("EC")` or `new SecretKeySpec(key, "HMACSHA256")`.
+* The `Signature.getInstance(...)` method is now modeled as a `CryptoAlgoSpec` sink, alongside the existing `Signature` constructor sink. This ensures that algorithm strings passed to `Signature.getInstance(...)` are also checked by the query.

java/ql/lib/semmle/code/java/security/Encryption.qll

@@ -259,7 +259,13 @@ string getASecureAlgorithmName() {
   result =
     [
       "RSA", "SHA-?(256|384|512)", "CCM", "GCM", "AES(?![^a-zA-Z](ECB|CBC/PKCS[57]Padding))",
-      "Blowfish", "ECIES", "SHA3-(256|384|512)"
+      "Blowfish", "ECIES", "SHA3-(256|384|512)",
+      // Elliptic Curve algorithms: EC (key generation), ECDSA (signatures), ECDH (key agreement),
+      // EdDSA/Ed25519/Ed448 (Edwards-curve signatures), XDH/X25519/X448 (key agreement).
+      // These are modern, secure algorithms recommended by NIST and other standards bodies.
+      "EC", "ECDSA", "ECDH", "EdDSA", "Ed25519", "Ed448", "XDH", "X25519", "X448",
+      // HMAC-based algorithms and key derivation functions.
+      "HMACSHA(1|256|384|512)", "HmacSHA(1|256|384|512)", "PBKDF2"
     ]
 }
 
@@ -366,9 +372,13 @@ class JavaSecuritySignature extends JavaSecurityAlgoSpec {
     exists(Constructor c | c.getAReference() = this |
       c.getDeclaringType().hasQualifiedName("java.security", "Signature")
     )
+    or
+    exists(Method m | m.getAReference() = this |
+      m.hasQualifiedName("java.security", "Signature", "getInstance")
+    )
   }
 
-  override Expr getAlgoSpec() { result = this.(ConstructorCall).getArgument(0) }
+  override Expr getAlgoSpec() { result = this.(Call).getArgument(0) }
 }
 
 /** A call to the `getInstance` method declared in `java.security.KeyPairGenerator`. */

java/ql/test/query-tests/security/CWE-327/semmle/tests/Test.java

@@ -46,6 +46,48 @@ public void test() {
 			cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
 
 			byte[] encrypted = cipher.doFinal(input.getBytes("UTF-8"));
+
+			KeyPairGenerator keyPairGenerator;
+
+			// GOOD: EC is a secure algorithm for key pair generation
+			keyPairGenerator = KeyPairGenerator.getInstance("EC");
+
+			// GOOD: ECDSA is a secure signature algorithm
+			Signature ecdsaSig = Signature.getInstance("ECDSA");
+
+			// GOOD: ECDH is a secure algorithm for key agreement
+			KeyAgreement ecdhKa = KeyAgreement.getInstance("ECDH");
+
+			// GOOD: EdDSA is a secure algorithm (Edwards-curve Digital Signature Algorithm)
+			keyPairGenerator = KeyPairGenerator.getInstance("EdDSA");
+
+			// GOOD: Ed25519 is a secure algorithm for key pair generation
+			keyPairGenerator = KeyPairGenerator.getInstance("Ed25519");
+
+			// GOOD: Ed448 is a secure algorithm for key pair generation
+			keyPairGenerator = KeyPairGenerator.getInstance("Ed448");
+
+			// GOOD: XDH is a secure algorithm for key agreement
+			KeyAgreement xdhKa = KeyAgreement.getInstance("XDH");
+
+			// GOOD: X25519 is a secure algorithm for key agreement
+			KeyAgreement x25519Ka = KeyAgreement.getInstance("X25519");
+
+			// GOOD: X448 is a secure algorithm for key agreement
+			KeyAgreement x448Ka = KeyAgreement.getInstance("X448");
+
+			// GOOD: SHA256withECDSA is a secure signature algorithm
+			Signature sha256Ecdsa = Signature.getInstance("SHA256withECDSA");
+
+			// GOOD: HMAC-based SecretKeySpec should not be flagged
+			new SecretKeySpec(null, "HMACSHA1");
+			new SecretKeySpec(null, "HMACSHA256");
+			new SecretKeySpec(null, "HMACSHA384");
+			new SecretKeySpec(null, "SHA384withECDSA");
+
+			// GOOD: PBKDF2 key derivation is a secure algorithm
+			SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
+
 		} catch (Exception e) {
 			// fail
 		}