Display in hex via helper class.

.gitignore

@@ -362,4 +362,5 @@ MigrationBackup/
 # Fody - auto-generated XML schema
 FodyWeavers.xsd
 /.vscode/launch.json
-/powershellYK.psd1
+/powershellYK.psd1
+/.cursorrules

Module/Cmdlets/OTP/SetYubikeyOTP.cs

@@ -46,6 +46,10 @@
 /// Set-YubiKeyOTP -Slot ShortPress -HOTP -Base32Secret "QRFJ7DTIVASL3PNYXWFIQAQN5RKUJD4U" -AppendCarriageReturn
 /// 
 /// .EXAMPLE
+/// # Configure HOTP with hex encoded secret and carriage return
+/// Set-YubiKeyOTP -Slot ShortPress -HOTP -HexSecret "0102030405060708090a0b0c0d0e0f1011121314" -AppendCarriageReturn
+/// 
+/// .EXAMPLE
 /// # Configure HOTP with TAB before OTP code for easier form navigation
 /// Set-YubiKeyOTP -Slot ShortPress -HOTP -Base32Secret "QRFJ7DTIVASL3PNYXWFIQAQN5RKUJD4U" -SendTabFirst
 /// 
@@ -158,6 +162,10 @@ public class SetYubikeyOTPCommand : PSCmdlet
         [Parameter(Mandatory = false, ValueFromPipeline = false, HelpMessage = "Base32 encoded secret key for HOTP", ParameterSetName = "HOTP")]
         public string? Base32Secret { get; set; }
 
+        // Hex encoded secret key for HOTP mode
+        [Parameter(Mandatory = false, ValueFromPipeline = false, HelpMessage = "Hex encoded secret key for HOTP", ParameterSetName = "HOTP")]
+        public string? HexSecret { get; set; }
+
         // Use 8 digits instead of 6 for HOTP mode
         [Parameter(Mandatory = false, ValueFromPipeline = false, HelpMessage = "Use 8 digits instead of 6 for HOTP", ParameterSetName = "HOTP")]
         public SwitchParameter Use8Digits { get; set; }
@@ -326,12 +334,18 @@ protected override void ProcessRecord()
                             Memory<byte> _HOTPsecretKey = new Memory<byte>(new byte[20]);
                             ConfigureHotp configureHOTP = otpSession.ConfigureHotp(Slot);
 
-                            // Handle Secret Key configuration
+                            // Handle Secret Key configuration using Base32
                             if (Base32Secret != null)
                             {
                                 _HOTPsecretKey = powershellYK.support.Base32.Decode(Base32Secret);
                                 configureHOTP = configureHOTP.UseKey(_HOTPsecretKey);
                             }
+                            // Handle Secret Key configuration using Hex
+                            else if (HexSecret != null)
+                            {
+                                _HOTPsecretKey = powershellYK.support.Hex.Decode(HexSecret);
+                                configureHOTP = configureHOTP.UseKey(_HOTPsecretKey);
+                            }
                             else if (SecretKey is null)
                             {
                                 configureHOTP = configureHOTP.GenerateKey(_HOTPsecretKey);
@@ -362,10 +376,10 @@ protected override void ProcessRecord()
 
                             configureHOTP.Execute();
 
-                            // Return both raw and Base32 representations of the key
+                            // Return both Hex and Base32 representations of the key
                             WriteObject(new
                             {
-                                SecretKey = _HOTPsecretKey.ToArray(),
+                                HexSecret = powershellYK.support.Hex.Encode(_HOTPsecretKey.ToArray()),
                                 Base32Secret = powershellYK.support.Base32.Encode(_HOTPsecretKey.ToArray())
                             });
                             break;

Module/support/Hex.cs

@@ -0,0 +1,59 @@
+/// <summary>
+/// Utility class for hex encoding and decoding.
+/// Provides methods to convert between byte arrays and hex strings.
+/// 
+/// .EXAMPLE
+/// # Encode a byte array to hex
+/// $bytes = [byte[]]@(1,2,3,4,5)
+/// $hex = [powershellYK.support.Hex]::Encode($bytes)
+/// 
+/// .EXAMPLE
+/// # Decode a hex string to bytes
+/// $hex = "0102030405"
+/// $bytes = [powershellYK.support.Hex]::Decode($hex)
+/// </summary>
+
+using System;
+using System.Linq;
+
+namespace powershellYK.support
+{
+    public static class Hex
+    {
+        // Encodes a byte array to a hex string
+        public static string Encode(byte[] data)
+        {
+            if (data == null)
+                throw new ArgumentNullException(nameof(data));
+
+            if (data.Length == 0)
+                return string.Empty;
+
+            return string.Concat(data.Select(b => b.ToString("x2")));
+        }
+
+        // Decodes a hex string to a byte array
+        public static byte[] Decode(string hexString)
+        {
+            if (string.IsNullOrEmpty(hexString))
+                return Array.Empty<byte>();
+
+            // Remove any whitespace and convert to lowercase
+            hexString = hexString.Replace(" ", "").ToLower();
+
+            // Ensure the string has an even length
+            if (hexString.Length % 2 != 0)
+                throw new ArgumentException("Hex string must have an even length");
+
+            // Convert each pair of hex characters to a byte
+            byte[] result = new byte[hexString.Length / 2];
+            for (int i = 0; i < result.Length; i++)
+            {
+                string hexPair = hexString.Substring(i * 2, 2);
+                result[i] = Convert.ToByte(hexPair, 16);
+            }
+
+            return result;
+        }
+    }
+}