Fix GOST 2012 SPKI algorithm OID for legacy CryptoPro parameter sets

crypto/src/x509/SubjectPublicKeyInfoFactory.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 
 using Org.BouncyCastle.Asn1;
 using Org.BouncyCastle.Asn1.CryptoPro;
@@ -27,15 +26,6 @@ namespace Org.BouncyCastle.X509
     /// </remarks>
     public static class SubjectPublicKeyInfoFactory
     {
-        private static readonly HashSet<DerObjectIdentifier> cryptoProOids = new HashSet<DerObjectIdentifier>
-        {
-            CryptoProObjectIdentifiers.GostR3410x2001CryptoProA,
-            CryptoProObjectIdentifiers.GostR3410x2001CryptoProB,
-            CryptoProObjectIdentifiers.GostR3410x2001CryptoProC,
-            CryptoProObjectIdentifiers.GostR3410x2001CryptoProXchA,
-            CryptoProObjectIdentifiers.GostR3410x2001CryptoProXchB,
-        };
-
         /// <summary>
         /// Create a <see cref="SubjectPublicKeyInfo"/> object for a given public key.
         /// </summary>
@@ -98,7 +88,7 @@ public static SubjectPublicKeyInfo CreateSubjectPublicKeyInfo(AsymmetricKeyParam
                     int fieldSize = ecKey.Parameters.Curve.FieldElementEncodingLength;
                     DerObjectIdentifier algOid;
 
-                    if (cryptoProOids.Contains(gostParams.PublicKeyParamSet))
+                    if (CryptoProObjectIdentifiers.GostR3411x94CryptoProParamSet.Equals(gostParams.DigestParamSet))
                     {
                         algOid = CryptoProObjectIdentifiers.GostR3410x2001;
                     }

crypto/test/src/test/Gost2012CryptoProSpkiTest.cs

@@ -0,0 +1,66 @@
+using System;
+
+using NUnit.Framework;
+
+using Org.BouncyCastle.Asn1.CryptoPro;
+using Org.BouncyCastle.Asn1.Rosstandart;
+using Org.BouncyCastle.Crypto.Generators;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Crypto.Utilities;
+using Org.BouncyCastle.Security;
+using Org.BouncyCastle.Utilities.Test;
+using Org.BouncyCastle.X509;
+
+namespace Org.BouncyCastle.Tests
+{
+    /// <summary>
+    /// Unit test to verify that GOST R 34.10-2012 keys using legacy CryptoPro parameter sets
+    /// are encoded with the correct GOST 2012 Algorithm OID in SubjectPublicKeyInfo (per RFC 9215).
+    /// </summary>
+    [TestFixture]
+    public class Gost2012CryptoProSpkiTest
+        : SimpleTest
+    {
+        public override string Name => "Gost2012CryptoProSpki";
+
+        public override void PerformTest()
+        {
+            // 1. Select a legacy CryptoPro curve OID (GOST R 34.10-2001 parameter set)
+            var curveOid = CryptoProObjectIdentifiers.GostR3410x2001CryptoProA; 
+            var domain = ECGost3410NamedCurves.GetByOid(curveOid);
+            var namedDomain = new ECNamedDomainParameters(curveOid, domain);
+
+            // 2. Configure key parameters with a GOST 2012 (256-bit) digest OID
+            var gostParameters = new ECGost3410Parameters(
+                namedDomain,
+                curveOid,
+                RosstandartObjectIdentifiers.id_tc26_gost_3411_12_256,
+                null);
+
+            // 3. Generate a key pair based on GOST 2012 parameters
+            var keyGen = new ECKeyPairGenerator();
+            keyGen.Init(new ECKeyGenerationParameters(gostParameters, new SecureRandom()));
+            var keyPair = keyGen.GenerateKeyPair();
+
+            // 4. Wrap the public key into SubjectPublicKeyInfo structure
+            var spki = SubjectPublicKeyInfoFactory.CreateSubjectPublicKeyInfo(keyPair.Public);
+
+            string actualAlgOid = spki.Algorithm.Algorithm.Id;
+            string expectedAlgOid = RosstandartObjectIdentifiers.id_tc26_gost_3410_12_256.Id;
+
+            // 5. Assert that the algorithm OID corresponds to GOST 2012 rather than GOST 2001
+            if (!expectedAlgOid.Equals(actualAlgOid))
+            {
+                Fail($"Expected GOST 2012 OID ({expectedAlgOid}), but got ({actualAlgOid})");
+            }
+        }
+
+        [Test]
+        public void TestFunction()
+        {
+            string resultText = Perform().ToString();
+
+            Assert.AreEqual(Name + ": Okay", resultText);
+        }
+    }
+}