aspnetcore/security/app-secrets/includes/app-secrets-3-5.md
:::moniker range="< aspnetcore-6.0"
<!-- ms.sfi.ropc: t -->By Rick Anderson, Kirk Larkin, Daniel Roth, and Scott Addie
View or download sample code (how to download)
This article explains how to manage sensitive data for an ASP.NET Core app on a development machine. Never store passwords or other sensitive data in source code or configuration files. Production secrets shouldn't be used for development or test. Secrets shouldn't be deployed with the app. Production secrets should be accessed through a controlled means like Azure Key Vault. Azure test and production secrets can be stored and protected with the Azure Key Vault configuration provider.
For more information on authentication for test and production environments, see Secure authentication flows.
Environment variables are used to avoid storage of app secrets in code or in local configuration files. Environment variables override configuration values for all previously specified configuration sources.
Consider an ASP.NET Core web app in which Individual User Accounts security is enabled. A default database connection string is included in the project's appsettings.json file with the key DefaultConnection. The default connection string is for LocalDB, which runs in user mode and doesn't require a password. During app deployment, the DefaultConnection key value can be overridden with an environment variable's value. The environment variable may store the complete connection string with sensitive credentials.
[!WARNING] Environment variables are generally stored in plain, unencrypted text. If the machine or process is compromised, environment variables can be accessed by untrusted parties. Additional measures to prevent disclosure of user secrets may be required.
The Secret Manager tool stores sensitive data during application development. In this context, a piece of sensitive data is an app secret. App secrets are stored in a separate location from the project tree. The app secrets are associated with a specific project or shared across several projects. The app secrets aren't checked into source control.
[!WARNING] The Secret Manager tool doesn't encrypt the stored secrets and shouldn't be treated as a trusted store. It's for development purposes only. The keys and values are stored in a JSON configuration file in the user profile directory.
The Secret Manager tool hides implementation details, such as where and how the values are stored. You can use the tool without knowing these implementation details. The values are stored in a JSON file in the local machine's user profile folder:
File system path:
%APPDATA%\Microsoft\UserSecrets\<user_secrets_id>\secrets.json
File system path:
~/.microsoft/usersecrets/<user_secrets_id>/secrets.json
In the preceding file paths, replace <user_secrets_id> with the UserSecretsId value specified in the project file.
Don't write code that depends on the location or format of data saved with the Secret Manager tool. These implementation details may change. For example, the secret values aren't encrypted, but could be in the future.
The Secret Manager tool operates on project-specific configuration settings stored in your user profile.
The Secret Manager tool includes an init command in .NET Core SDK 3.0.100 or later. To use user secrets, run the following command in the project directory:
dotnet user-secrets init
The preceding command adds a UserSecretsId element within a PropertyGroup of the project file. By default, the inner text of UserSecretsId is a GUID. The inner text is arbitrary, but is unique to the project.
In Visual Studio, right-click the project in Solution Explorer, and select Manage User Secrets from the context menu. This gesture adds a UserSecretsId element, populated with a GUID, to the project file.
Define an app secret consisting of a key and its value. The secret is associated with the project's UserSecretsId value. For example, run the following command from the directory in which the project file exists:
dotnet user-secrets set "Movies:ServiceApiKey" "12345"
In the preceding example, the colon denotes that Movies is an object literal with a ServiceApiKey property.
The Secret Manager tool can be used from other directories too. Use the --project option to supply the file system path at which the project file exists. For example:
dotnet user-secrets set "Movies:ServiceApiKey" "12345" --project "C:\apps\WebApp1\src\WebApp1"
Visual Studio's Manage User Secrets gesture opens a secrets.json file in the text editor. Replace the contents of secrets.json with the key-value pairs to be stored. For example:
{
"Movies": {
"ConnectionString": "Server=(localdb)\\mssqllocaldb;Database=Movie-1;Trusted_Connection=True;MultipleActiveResultSets=true",
"ServiceApiKey": "12345"
}
}
The JSON structure is flattened after modifications via dotnet user-secrets remove or dotnet user-secrets set. For example, running dotnet user-secrets remove "Movies:ConnectionString" collapses the Movies object literal. The modified file resembles the following JSON:
{
"Movies:ServiceApiKey": "12345"
}
A batch of secrets can be set by piping JSON to the set command. In the following example, the input.json file's contents are piped to the set command.
Open a command shell, and execute the following command:
type .\input.json | dotnet user-secrets set
Open a command shell, and execute the following command:
cat ./input.json | dotnet user-secrets set
To access a secret, complete the following steps:
The user secrets configuration provider registers the appropriate configuration source with the .NET Configuration API.
The user secrets configuration source is automatically added in Development mode when the project calls xref:Microsoft.Extensions.Hosting.Host.CreateDefaultBuilder%2A. CreateDefaultBuilder calls xref:Microsoft.Extensions.Configuration.UserSecretsConfigurationExtensions.AddUserSecrets%2A when the xref:Microsoft.Extensions.Hosting.IHostEnvironment.EnvironmentName is xref:Microsoft.Extensions.Hosting.EnvironmentName.Development:
When CreateDefaultBuilder isn't called, add the user secrets configuration source explicitly by calling xref:Microsoft.Extensions.Configuration.UserSecretsConfigurationExtensions.AddUserSecrets%2A in xref:Microsoft.Extensions.Hosting.HostBuilder.ConfigureAppConfiguration%2A. Call AddUserSecrets only when the app runs in the Development environment, as shown in the following example:
If the user secrets configuration source is registered, the .NET Configuration API can read the secrets. Constructor injection can be used to gain access to the .NET Configuration API. Consider the following examples of reading the Movies:ServiceApiKey key:
Startup class:
Razor Pages page model:
For more information, see Access configuration in Startup and Access configuration in Razor Pages.
Mapping an entire object literal to a POCO (a simple .NET class with properties) is useful for aggregating related properties.
[!INCLUDEsecrets.json file]
To map the preceding secrets to a POCO, use the .NET Configuration API's object graph binding feature. The following code binds to a custom MovieSettings POCO and accesses the ServiceApiKey property value:
The Movies:ConnectionString and Movies:ServiceApiKey secrets are mapped to the respective properties in MovieSettings:
Storing passwords in plain text is insecure. Never store secrets in a configuration file such as appsettings.json, which might get checked in to a source code repository.
For example, a database connection string stored in appsettings.json should not include a password. Instead, store the password as a secret, and include the password in the connection string at runtime. For example:
dotnet user-secrets set "DbPassword" "<secret value>"
Replace the <secret value> placeholder in the preceding example with the password value. Set the secret's value on a xref:System.Data.SqlClient.SqlConnectionStringBuilder object's xref:System.Data.SqlClient.SqlConnectionStringBuilder.Password%2A property to include it as the password value in the connection string:
[!INCLUDEsecrets.json file]
Run the following command from the directory in which the project file exists:
dotnet user-secrets list
The following output appears:
Movies:ConnectionString = Server=(localdb)\mssqllocaldb;Database=Movie-1;Trusted_Connection=True;MultipleActiveResultSets=true
Movies:ServiceApiKey = 12345
In the preceding example, a colon in the key names denotes the object hierarchy within secrets.json.
[!INCLUDEsecrets.json file]
Run the following command from the directory in which the project file exists:
dotnet user-secrets remove "Movies:ConnectionString"
The app's secrets.json file was modified to remove the key-value pair associated with the MoviesConnectionString key:
{
"Movies": {
"ServiceApiKey": "12345"
}
}
dotnet user-secrets list displays the following message:
Movies:ServiceApiKey = 12345
[!INCLUDEsecrets.json file]
Run the following command from the directory in which the project file exists:
dotnet user-secrets clear
All user secrets for the app have been deleted from the secrets.json file:
{}
Running dotnet user-secrets list displays the following message:
No secrets configured for this application.
<a name="muswvs"></a>
To manage user secrets in Visual Studio, right click the project in solution explorer and select Manage User Secrets:
See this GitHub issue.
Projects that target Microsoft.NET.Sdk.Web automatically include support for user secrets. For projects that target Microsoft.NET.Sdk, such as console applications, install the configuration extension and user secrets NuGet packages explicitly.
Using PowerShell:
Install-Package Microsoft.Extensions.Configuration
Install-Package Microsoft.Extensions.Configuration.UserSecrets
Using the .NET CLI:
dotnet add package Microsoft.Extensions.Configuration
dotnet add package Microsoft.Extensions.Configuration.UserSecrets
Once the packages are installed, initialize the project and set secrets the same way as for a web app. The following example shows a console application that retrieves the value of a secret that was set with the key "AppSecret":
using Microsoft.Extensions.Configuration;
namespace ConsoleApp;
class Program
{
static void Main(string[] args)
{
IConfigurationRoot config = new ConfigurationBuilder()
.AddUserSecrets<Program>()
.Build();
Console.WriteLine(config["AppSecret"]);
}
}
:::moniker-end