diff --git a/java/ql/lib/change-notes/2026-03-27-add-ec-to-secure-algorithms.md b/java/ql/lib/change-notes/2026-03-27-add-ec-to-secure-algorithms.md
new file mode 100644
index 000000000000..ee53bedd4176
--- /dev/null
+++ b/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. This will reduce the number of false positives for this query.
+* The first argument of the method `getInstance` of `java.security.Signature` is now modeled as a sink for `java/potentially-weak-cryptographic-algorithm`, `java/weak-cryptographic-algorithm` and `java/rsa-without-oaep`. This will increase the number of alerts for these queries.
diff --git a/java/ql/lib/semmle/code/java/security/Encryption.qll b/java/ql/lib/semmle/code/java/security/Encryption.qll
index b0a0fc72df77..6af8d29cc4a1 100644
--- a/java/ql/lib/semmle/code/java/security/Encryption.qll
+++ b/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`. */
diff --git a/java/ql/test/query-tests/security/CWE-327/semmle/tests/Test.java b/java/ql/test/query-tests/security/CWE-327/semmle/tests/Test.java
index 2f66d4996393..23aff65161c9 100644
--- a/java/ql/test/query-tests/security/CWE-327/semmle/tests/Test.java
+++ b/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
 		}