From 8dd93e2929bb5ef6504626a983b4249aee8b65df Mon Sep 17 00:00:00 2001
From: JKorf <jankorf91@gmail.com>
Date: Tue, 9 Dec 2025 21:13:01 +0100
Subject: [PATCH] wip

---
 .../Authentication/ApiCredentials.cs          | 12 ++++
 .../Authentication/ApiCredentialsType.cs      |  6 +-
 .../Authentication/AuthenticationProvider.cs  | 56 +++++++++++++++++++
 CryptoExchange.Net/CryptoExchange.Net.csproj  |  1 +
 4 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/CryptoExchange.Net/Authentication/ApiCredentials.cs b/CryptoExchange.Net/Authentication/ApiCredentials.cs
index f5a2ca4..1b1cbab 100644
--- a/CryptoExchange.Net/Authentication/ApiCredentials.cs
+++ b/CryptoExchange.Net/Authentication/ApiCredentials.cs
@@ -1,4 +1,6 @@
 using System;
+using System.IO;
+using System.Threading.Tasks;
 
 namespace CryptoExchange.Net.Authentication
 {
@@ -45,6 +47,16 @@ namespace CryptoExchange.Net.Authentication
             Pass = pass;
         }
 
+        /// <summary>
+        /// Load a private key from a file path
+        /// </summary>
+        public async Task<string> LoadPrivateKey(string path)
+        {
+            using var filestream = File.OpenRead(path);
+            using var streamReader = new StreamReader(filestream);
+            return await streamReader.ReadToEndAsync().ConfigureAwait(false);
+        }
+
         /// <summary>
         /// Copy the credentials
         /// </summary>
diff --git a/CryptoExchange.Net/Authentication/ApiCredentialsType.cs b/CryptoExchange.Net/Authentication/ApiCredentialsType.cs
index 2da474f..63b0281 100644
--- a/CryptoExchange.Net/Authentication/ApiCredentialsType.cs
+++ b/CryptoExchange.Net/Authentication/ApiCredentialsType.cs
@@ -16,6 +16,10 @@
         /// <summary>
         /// Rsa keys credentials in pem/base64 format. Only available for .NetStandard 2.1 and up, use xml format for lower.
         /// </summary>
-        RsaPem
+        RsaPem,
+        /// <summary>
+        /// Ed25519 keys credentials
+        /// </summary>
+        Ed25519
     }
 }
diff --git a/CryptoExchange.Net/Authentication/AuthenticationProvider.cs b/CryptoExchange.Net/Authentication/AuthenticationProvider.cs
index f6a291d..7a4112f 100644
--- a/CryptoExchange.Net/Authentication/AuthenticationProvider.cs
+++ b/CryptoExchange.Net/Authentication/AuthenticationProvider.cs
@@ -2,8 +2,12 @@
 using CryptoExchange.Net.Converters.SystemTextJson;
 using CryptoExchange.Net.Interfaces;
 using CryptoExchange.Net.Objects;
+#if NET8_0_OR_GREATER
+using NSec.Cryptography;
+#endif
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Globalization;
 using System.Security.Cryptography;
 using System.Text;
@@ -17,6 +21,11 @@ namespace CryptoExchange.Net.Authentication
     {
         internal IAuthTimeProvider TimeProvider { get; set; } = new AuthTimeProvider();
 
+        /// <summary>
+        /// The supported credential types
+        /// </summary>
+        public abstract ApiCredentialsType[] SupportedCredentialTypes { get; }
+
         /// <summary>
         /// Provided credentials
         /// </summary>
@@ -27,6 +36,13 @@ namespace CryptoExchange.Net.Authentication
         /// </summary>
         protected byte[] _sBytes;
 
+#if NET8_0_OR_GREATER
+        /// <summary>
+        /// The Ed25519 private key
+        /// </summary>
+        protected Key? Ed25519Key;
+#endif
+
         /// <summary>
         /// Get the API key of the current credentials
         /// </summary>
@@ -45,6 +61,16 @@ namespace CryptoExchange.Net.Authentication
             if (credentials.Key == null || credentials.Secret == null)
                 throw new ArgumentException("ApiKey/Secret needed");
 
+            if (!SupportedCredentialTypes.Any(x => x == credentials.CredentialType))
+                throw new ArgumentException($"Credential type {credentials.CredentialType} not supported");
+
+            if (credentials.CredentialType == ApiCredentialsType.Ed25519)
+            {
+#if !NET8_0_OR_GREATER
+                throw new ArgumentException($"Credential type Ed25519 only supported on Net8.0 or newer");
+#endif
+            }
+
             _credentials = credentials;
             _sBytes = Encoding.UTF8.GetBytes(credentials.Secret);
         }
@@ -348,6 +374,36 @@ namespace CryptoExchange.Net.Authentication
             return outputType == SignOutputType.Base64 ? BytesToBase64String(resultBytes) : BytesToHexString(resultBytes);
         }
 
+        /// <summary>
+        /// Ed25519 sign the data 
+        /// </summary>
+        public string SignEd25519(string data, SignOutputType? outputType = null)
+            => SignEd25519(Encoding.ASCII.GetBytes(data), outputType);
+
+        /// <summary>
+        /// Ed25519 sign the data 
+        /// </summary>
+        public string SignEd25519(byte[] data, SignOutputType? outputType = null)
+        {
+#if NET8_0_OR_GREATER
+            if (Ed25519Key == null)
+            {
+                var key = _credentials.Secret!
+                        .Replace("\n", "")
+                        .Replace("-----BEGIN PRIVATE KEY-----", "")
+                        .Replace("-----END PRIVATE KEY-----", "")
+                        .Trim();
+                var keyBytes = Convert.FromBase64String(key);
+                Ed25519Key = Key.Import(SignatureAlgorithm.Ed25519, keyBytes, KeyBlobFormat.PkixPrivateKey);
+            }
+
+            var resultBytes = SignatureAlgorithm.Ed25519.Sign(Ed25519Key, data);
+            return outputType == SignOutputType.Base64 ? BytesToBase64String(resultBytes) : BytesToHexString(resultBytes);
+#else
+            throw new InvalidOperationException();
+#endif
+        }
+
         private RSA CreateRSA()
         {
             var rsa = RSA.Create();
diff --git a/CryptoExchange.Net/CryptoExchange.Net.csproj b/CryptoExchange.Net/CryptoExchange.Net.csproj
index 864a3bf..041b40f 100644
--- a/CryptoExchange.Net/CryptoExchange.Net.csproj
+++ b/CryptoExchange.Net/CryptoExchange.Net.csproj
@@ -53,6 +53,7 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.Logging" Version="10.0.0" />
     <PackageReference Include="System.Text.Json" Version="10.0.0" />
+    <PackageReference Include="NSec.Cryptography" Version="25.4.0" Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net8.0'))" />
   </ItemGroup>
   <ItemGroup Label="Transitive Client Packages">
     <PackageReference Include="Microsoft.Extensions.Configuration.Binder" Version="10.0.0" />