1 files changed, 96 insertions, 0 deletions
diff --git a/crypto/src/util/ssh/SSHNamedCurves.cs b/crypto/src/util/ssh/SSHNamedCurves.cs
new file mode 100644
index 000000000..31c350128
--- /dev/null
+++ b/crypto/src/util/ssh/SSHNamedCurves.cs
@@ -0,0 +1,96 @@
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.Nist;
+using Org.BouncyCastle.Asn1.Sec;
+using Org.BouncyCastle.Asn1.X9;
+using Org.BouncyCastle.Crypto.EC;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Math.EC;
+using System;
+using System.Collections.Generic;
+using System.Drawing;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Org.BouncyCastle.Utilities.SSH
+{
+    public class SSHNamedCurves
+    {
+        private static readonly Dictionary<string, DerObjectIdentifier> OidMap =
+            new Dictionary<string, DerObjectIdentifier>
+            {
+                { "nistp256", SecObjectIdentifiers.SecP256r1 },
+                { "nistp384", SecObjectIdentifiers.SecP384r1 },
+                { "nistp521", SecObjectIdentifiers.SecP521r1 },
+                { "nistk163", SecObjectIdentifiers.SecT163k1 },
+                { "nistp192", SecObjectIdentifiers.SecP192r1 },
+                { "nistp224", SecObjectIdentifiers.SecP224r1 },
+                { "nistk233", SecObjectIdentifiers.SecT233k1 },
+                { "nistb233", SecObjectIdentifiers.SecT233r1 },
+                { "nistk283", SecObjectIdentifiers.SecT283k1 },
+                { "nistk409", SecObjectIdentifiers.SecT409k1 },
+                { "nistb409", SecObjectIdentifiers.SecT409r1 },
+                { "nistt571", SecObjectIdentifiers.SecT571k1 }
+            };
+
+
+        private static readonly Dictionary<string, string> CurveNameToSSHName = 
+            new Dictionary<string, string>
+            {
+                {"secp256r1", "nistp256"},
+                {"secp384r1", "nistp384"},
+                {"secp521r1", "nistp521"},
+                {"sect163k1", "nistk163"},
+                {"secp192r1", "nistp192"},
+                {"secp224r1", "nistp224"},
+                {"sect233k1", "nistk233"},
+                {"sect233r1", "nistb233"},
+                {"sect283k1", "nistk283"},
+                {"sect409k1", "nistk409"},
+                {"sect409r1", "nistb409"},
+                {"sect571k1", "nistt571"}
+            };
+
+        private static readonly Dictionary<ECCurve, string> CurveMap = 
+            CustomNamedCurves.Names.ToDictionary(k => CustomNamedCurves.GetByNameLazy(k).Curve, v => v);
+
+        private static readonly Dictionary<DerObjectIdentifier, string> OidToName =
+            OidMap.ToDictionary(k => k.Value, v => v.Key);
+
+
+        public static DerObjectIdentifier GetByName(string sshName)
+        {
+            return OidMap[sshName];
+        }
+
+        public static X9ECParameters GetParameters(string sshName)
+        {
+            return NistNamedCurves.GetByOid(OidMap[sshName.ToLower()]);
+        }
+
+        public static X9ECParameters GetParameters(DerObjectIdentifier oid)
+        {
+            return NistNamedCurves.GetByOid(oid);
+        }
+
+        public static string GetName(DerObjectIdentifier oid)
+        {
+            return OidToName[oid];
+        }
+
+        public static string GetNameForParameters(ECDomainParameters parameters)
+        {
+            if (parameters is ECNamedDomainParameters)
+            {
+                return GetName(((ECNamedDomainParameters)parameters).Name);
+            }
+
+            return GetNameForParameters(parameters.Curve);
+        }
+
+        public static string GetNameForParameters(ECCurve curve)
+        {
+            return CurveNameToSSHName[CurveMap[curve]];
+        }
+    }
+}