3 files changed, 32 insertions, 4 deletions
diff --git a/crypto/src/asn1/Asn1InputStream.cs b/crypto/src/asn1/Asn1InputStream.cs
index 96b0a1c66..a1bc987cc 100644
--- a/crypto/src/asn1/Asn1InputStream.cs
+++ b/crypto/src/asn1/Asn1InputStream.cs
@@ -377,7 +377,9 @@ namespace Org.BouncyCastle.Asn1
             switch (tagNo)
             {
             case Asn1Tags.BmpString:
+            {
                 return CreateDerBmpString(defIn);
+            }
             case Asn1Tags.Boolean:
             {
                 GetBuffer(defIn, tmpBuffers, out var contents);
@@ -393,6 +395,11 @@ namespace Org.BouncyCastle.Asn1
                 bool usedBuffer = GetBuffer(defIn, tmpBuffers, out var contents);
                 return DerObjectIdentifier.CreatePrimitive(contents, clone: usedBuffer);
             }
+            case Asn1Tags.RelativeOid:
+            {
+                bool usedBuffer = GetBuffer(defIn, tmpBuffers, out var contents);
+                return Asn1RelativeOid.CreatePrimitive(contents, clone: usedBuffer);
+            }
             }
 
             byte[] bytes = defIn.ToArray();
@@ -421,8 +428,6 @@ namespace Org.BouncyCastle.Asn1
                 return Asn1OctetString.CreatePrimitive(bytes);
             case Asn1Tags.PrintableString:
                 return DerPrintableString.CreatePrimitive(bytes);
-            case Asn1Tags.RelativeOid:
-                return Asn1RelativeOid.CreatePrimitive(bytes, false);
             case Asn1Tags.T61String:
                 return DerT61String.CreatePrimitive(bytes);
             case Asn1Tags.UniversalString:
diff --git a/crypto/src/asn1/Asn1RelativeOid.cs b/crypto/src/asn1/Asn1RelativeOid.cs
index f43a85479..3e2b54c9e 100644
--- a/crypto/src/asn1/Asn1RelativeOid.cs
+++ b/crypto/src/asn1/Asn1RelativeOid.cs
@@ -1,6 +1,7 @@
 using System;
 using System.IO;
 using System.Text;
+using System.Threading;
 
 using Org.BouncyCastle.Math;
 using Org.BouncyCastle.Utilities;
@@ -80,6 +81,8 @@ namespace Org.BouncyCastle.Asn1
 
         private const long LongLimit = (long.MaxValue >> 7) - 0x7F;
 
+        private static readonly Asn1RelativeOid[] Cache = new Asn1RelativeOid[64];
+
         private readonly byte[] m_contents;
         private string m_identifier;
 
@@ -167,7 +170,27 @@ namespace Org.BouncyCastle.Asn1
 
         internal static Asn1RelativeOid CreatePrimitive(byte[] contents, bool clone)
         {
-            return new Asn1RelativeOid(contents, clone);
+            uint index = (uint)Arrays.GetHashCode(contents);
+
+            index ^= index >> 24;
+            index ^= index >> 12;
+            index ^= index >> 6;
+            index &= 63;
+
+            var originalEntry = Volatile.Read(ref Cache[index]);
+            if (originalEntry != null && Arrays.AreEqual(contents, originalEntry.m_contents))
+                return originalEntry;
+
+            var newEntry = new Asn1RelativeOid(contents, clone);
+
+            var exchangedEntry = Interlocked.CompareExchange(ref Cache[index], newEntry, originalEntry);
+            if (exchangedEntry != originalEntry)
+            {
+                if (exchangedEntry != null && Arrays.AreEqual(contents, exchangedEntry.m_contents))
+                    return exchangedEntry;
+            }
+
+            return newEntry;
         }
 
         internal static bool IsValidContents(byte[] contents)
diff --git a/crypto/src/asn1/DerObjectIdentifier.cs b/crypto/src/asn1/DerObjectIdentifier.cs
index 04792cbdd..51acd232c 100644
--- a/crypto/src/asn1/DerObjectIdentifier.cs
+++ b/crypto/src/asn1/DerObjectIdentifier.cs
@@ -197,7 +197,7 @@ namespace Org.BouncyCastle.Asn1
 
         internal static DerObjectIdentifier CreatePrimitive(byte[] contents, bool clone)
         {
-            int index = Arrays.GetHashCode(contents);
+            uint index = (uint)Arrays.GetHashCode(contents);
 
             index ^= index >> 20;
             index ^= index >> 10;