diff --git a/src/CertGen/CommandOptions/CreateEcdsaCommandOptions.cs b/src/CertGen/CommandOptions/CreateEcdsaCommandOptions.cs
index 38913b4..fd7caea 100644
--- a/src/CertGen/CommandOptions/CreateEcdsaCommandOptions.cs
+++ b/src/CertGen/CommandOptions/CreateEcdsaCommandOptions.cs
@@ -13,7 +13,7 @@ public sealed class CreateEcdsaCommandOptionsBinder(
     Option<string> certName,
     Option<Algorithm> algorithm,
     Option<NamedCurve> namedCurve,
-    Option<string[]> dnsNames,
+    Option<IReadOnlyCollection<string>> dnsNames,
     Option<string?> pfxPassword,
     Option<string?> organizationName,
     Option<string?> organizationUnitName,
diff --git a/src/CertGen/CommandOptions/CreateRsaCommandOptions.cs b/src/CertGen/CommandOptions/CreateRsaCommandOptions.cs
index c662846..50a7033 100644
--- a/src/CertGen/CommandOptions/CreateRsaCommandOptions.cs
+++ b/src/CertGen/CommandOptions/CreateRsaCommandOptions.cs
@@ -13,7 +13,7 @@ public sealed class CreateRsaCommandOptionsBinder(
     Option<string> certName,
     Option<Algorithm> algorithm,
     Option<int> keySize,
-    Option<string[]> dnsNames,
+    Option<IReadOnlyCollection<string>> dnsNames,
     Option<string?> pfxPassword,
     Option<string?> organizationName,
     Option<string?> organizationUnitName,
@@ -28,8 +28,7 @@ public sealed class CreateRsaCommandOptionsBinder(
     commonName
 )
 {
-    protected override CreateRsaCommandOptions GetBoundValue([NotNull
-    ] BindingContext bindingContext) =>
+    protected override CreateRsaCommandOptions GetBoundValue([NotNull] BindingContext bindingContext) =>
         base.GetBoundValue(bindingContext) with
         {
             KeySize = bindingContext.ParseResult.GetValueForOption(keySize)
diff --git a/src/CertGen/CommandOptions/GlobalOptions.cs b/src/CertGen/CommandOptions/GlobalOptions.cs
index 4e203db..b50ad01 100644
--- a/src/CertGen/CommandOptions/GlobalOptions.cs
+++ b/src/CertGen/CommandOptions/GlobalOptions.cs
@@ -24,7 +24,7 @@ public record GlobalOptions
 public abstract class GlobalOptionsBinder<TOptions>(
     Option<string> certName,
     Option<Algorithm> algorithm,
-    Option<string[]> dnsNames,
+    Option<IReadOnlyCollection<string>> dnsNames,
     Option<string?> pfxPassword,
     Option<string?> organizationName,
     Option<string?> organizationUnitName,
diff --git a/src/CertGen/Handlers.cs b/src/CertGen/Handlers.cs
index 2cef3a7..30fc366 100644
--- a/src/CertGen/Handlers.cs
+++ b/src/CertGen/Handlers.cs
@@ -35,7 +35,7 @@ public static Command Initialize()
 
         algorithmOption.AddAlias("-a");
 
-        var dnsNamesOption = new Option<string[]>(
+        var dnsNamesOption = new Option<IReadOnlyCollection<string>>(
             name: "--dns-names",
             description: "DNS names for the certificate",
             getDefaultValue: () => ["localhost"]