From fac7ac9bfe82e7c4eedf5a7b26bed58e49fa988b Mon Sep 17 00:00:00 2001
From: David Hook <dgh@cryptoworkshop.com>
Date: Sat, 25 Apr 2020 13:11:33 +1000
Subject: github #237 - gost 2012 parsing

---
 crypto/src/asn1/pkcs/PrivateKeyInfo.cs         |  5 +++++
 crypto/src/security/PrivateKeyFactory.cs       | 20 +++++++++++++++-----
 crypto/test/src/security/test/TestEncodings.cs | 13 +++++++++++++
 3 files changed, 33 insertions(+), 5 deletions(-)

(limited to 'crypto')

diff --git a/crypto/src/asn1/pkcs/PrivateKeyInfo.cs b/crypto/src/asn1/pkcs/PrivateKeyInfo.cs
index ba9ef6a53..c5c7c3a2f 100644
--- a/crypto/src/asn1/pkcs/PrivateKeyInfo.cs
+++ b/crypto/src/asn1/pkcs/PrivateKeyInfo.cs
@@ -167,6 +167,11 @@ namespace Org.BouncyCastle.Asn1.Pkcs
             get { return privateKeyAlgorithm; }
         }
 
+        public virtual Asn1OctetString PrivateKeyData
+        {
+            get { return privateKey; }
+        } 
+
         public virtual Asn1Object ParsePrivateKey()
         {
             return Asn1Object.FromByteArray(privateKey.GetOctets());
diff --git a/crypto/src/security/PrivateKeyFactory.cs b/crypto/src/security/PrivateKeyFactory.cs
index b72ece365..4c7a91ecf 100644
--- a/crypto/src/security/PrivateKeyFactory.cs
+++ b/crypto/src/security/PrivateKeyFactory.cs
@@ -206,15 +206,25 @@ namespace Org.BouncyCastle.Security
                             gostParams.PublicKeyParamSet,
                             gostParams.DigestParamSet,
                             gostParams.EncryptionParamSet);
-                    Asn1Encodable privKey = keyInfo.ParsePrivateKey();
-                    if (privKey is DerInteger)
+
+                    Asn1OctetString privEnc = keyInfo.PrivateKeyData;
+                    if (privEnc.GetOctets().Length == 32 || privEnc.GetOctets().Length == 64)
                     {
-                        d = DerInteger.GetInstance(privKey).PositiveValue;
+                        byte[] dVal = Arrays.Reverse(privEnc.GetOctets());
+                        d = new BigInteger(1, dVal);
                     }
                     else
                     {
-                        byte[] dVal = Arrays.Reverse(Asn1OctetString.GetInstance(privKey).GetOctets());
-                        d = new BigInteger(1, dVal);
+                        Asn1Encodable privKey = keyInfo.ParsePrivateKey();
+                        if (privKey is DerInteger)
+                        {
+                            d = DerInteger.GetInstance(privKey).PositiveValue;
+                        }
+                        else
+                        {
+                            byte[] dVal = Arrays.Reverse(Asn1OctetString.GetInstance(privKey).GetOctets());
+                            d = new BigInteger(1, dVal);
+                        }
                     }
                 }
                 else
diff --git a/crypto/test/src/security/test/TestEncodings.cs b/crypto/test/src/security/test/TestEncodings.cs
index a70d5b5b7..91e1375dd 100644
--- a/crypto/test/src/security/test/TestEncodings.cs
+++ b/crypto/test/src/security/test/TestEncodings.cs
@@ -179,5 +179,18 @@ namespace Org.BouncyCastle.Security.Tests
             Assert.IsTrue(true, "DSATest worked.");
 
         }
+
+        [Test]
+        public void TestGost2012()
+        {
+            byte[] data = Base64.Decode(
+                "MIGiAgEAMCEGCCqFAwcBAQECMBUGCSqFAwcBAgECAQYIKoUDBwEBAgMEQIXnWrZ6"
+                + "ajvbCU6x9jK49PgQqCP00T/lW3laXCXueMF8X4Q1y3N9zfOJT2s/IgyPJVrUhgtO"
+                + "1Akp+Roh8bCPPlqgODA2BggqhQMCCQMIATEqBCi72ZvrBVW6mFL/bQeXeMTf8Jh8"
+                + "p/diI7Cg8ig4mXg3tsIUf4vBi61b");
+    
+            var keyInfo = PrivateKeyInfo.GetInstance(data);
+            var akp = Org.BouncyCastle.Security.PrivateKeyFactory.CreateKey(keyInfo);
+        }
     }
 }
-- 
cgit 1.4.1