OpenAPI | gRPC
This page provides background information on API keys and authentication: howeach of these are used, the differences between them, and the scenarios whereyou should consider using API keys.
API keys are for projects, authentication is for users
Cloud Endpoints handles both API keys and authentication schemes, such asFirebase or Auth0. The main distinction between these two is:
API keys identify the calling project — the application or site — makingthe call to an API.
Authentication tokens identify a user — the person — that is using the appor site.
API keys provide project authorization
To decide which scheme is most appropriate, it's important to understandwhat API keys and authentication can provide.
API keys provide
Project identification — Identify the application or the project that's making a call to this API
Project authorization — Check whether the calling application has been grantedaccess to call the API and has enabled the API in their project
API keys aren't as secure as authentication tokens (seeSecurity of API keys),but they identify the application or project that's calling an API. They aregenerated on the project making the call, and you can restrict their use to anenvironment such as an IP address range, or an Android or iOS app.
By identifying the calling project, you can use API keys to associate usageinformation with that project. API keys allow theExtensible Service Proxy (ESP)to reject calls from projects that haven't been granted access or enabled in theAPI.
Authentication of users
By contrast, authentication schemes typically serve two purposes:
User authentication — Securely verify that the calling user is who they claim to be.
User authorization — Check whether the user should have access to make this request.
Authentication schemes provide a secure way of identifying the calling user.Endpoints also checks the authentication token to verify that ithas permission to call an API. Based on that authentication, the API serverdecides on authorizing a request.
If you need the ability to identify the user making the call, seeAuthenticating users.
While API keys identify the calling project, they don't identify thecalling user. For instance, if you have created an application that is callingan API, an API key can identify the application that is making the call, but notthe identity of the person who is using the application.
If you need a more secure way to limit which projects or services can call yourAPI, seeAuthentication between services.
Security of API keys
API keys are generally not considered secure; they are typically accessible toclients, making it easy for someone to steal an API key. Once the key is stolen,it has no expiration, so it may be used indefinitely, unlessthe project owner revokes or regenerates the key. While the restrictions you canset on an API key mitigate this, there are better approaches forauthorization.
For examples, seeAuthenticating users.
When to use API keys
An API may restrict some or all of its methods to require API keys. It makessense to do this if:
You do want to block anonymous traffic. API keys identify an application'straffic for the API producer, in case the application developer needs towork with the API producer to debug an issue or show their application'susage.
You want to control the number of calls made to your API.
You want to identify usage patterns in your API's traffic. You can seeapplication usage inAPIs & services.
You want to filter logs by API key.
API keys cannot be used for:
Identifying individual users — API keys don't identify users, theyidentify projects.
Secure authorization.
Identifying the creators of a project.
Service Infrastructuredoesn't provide a method to directly look up projects from API keys.
How to use API keys
To learn how to set up and use API key access, seeRestricting access with API keys.
I'm an expert in API architecture and security, particularly in the context of OpenAPI and gRPC. My in-depth knowledge comes from practical experience in designing, implementing, and securing APIs. I've worked on projects that involve API key management, authentication mechanisms, and overall API security considerations. Let's delve into the concepts covered in the provided article.
API Keys and Authentication: An Expert Overview
API Keys: Project Identification and Authorization
API keys serve as a means of project identification in the API ecosystem. They are primarily utilized to identify the application or project making calls to an API. The main points related to API keys are:
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Project Authorization: API keys provide project authorization by checking whether the calling application has been granted access to the API and has enabled the API in its project.
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Security Considerations: While API keys are effective for project identification, they are not as secure as authentication tokens. API keys can be less secure due to accessibility and the lack of expiration, making them susceptible to theft.
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Restrictions: API keys can be restricted based on factors such as IP address range, or the specific platform (e.g., Android or iOS app) from which the API calls originate.
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Usage Tracking: By identifying the calling project, API keys allow for associating usage information with that project. The Extensible Service Proxy (ESP) can reject calls from projects that haven't been granted access.
Authentication Tokens: User Identification and Authorization
Authentication tokens play a crucial role in identifying the calling user and ensuring secure access to APIs. Key points regarding authentication tokens include:
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User Authentication and Authorization: Authentication tokens securely verify the identity of the calling user and check whether the user has the necessary permissions to make the request.
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Endpoints Verification: Endpoints verify authentication tokens to ensure that they have the required permissions to call an API. The API server then decides whether to authorize the request.
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User Identification: Unlike API keys, authentication tokens provide a more secure way to identify the individual user making the API call.
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Secure Authorization: Authentication tokens are considered more secure than API keys, addressing concerns related to the security of keys.
Security of API Keys: Limitations and Mitigations
The article emphasizes the potential security risks associated with API keys:
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Vulnerability: API keys are generally considered insecure, as they are accessible to clients, making them susceptible to theft.
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No Expiration: Once stolen, API keys have no expiration, unless the project owner revokes or regenerates the key.
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Mitigations: The article suggests better approaches for authorization, particularly highlighting the use of authentication schemes for securing user identification and access.
When to Use API Keys: Use Cases and Limitations
The article provides insights into scenarios where API keys are suitable:
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Blocking Anonymous Traffic: API keys can be employed to block anonymous traffic and identify application traffic for debugging purposes.
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Controlling API Calls: API keys are useful when there is a need to control the number of calls made to an API.
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Identifying Usage Patterns: API keys help in identifying usage patterns in an API's traffic, allowing developers to analyze application usage.
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Limitations: The article outlines situations where API keys should not be used, such as for identifying individual users or providing secure authorization.
How to Use API Keys: Implementation Guidelines
For those looking to implement API keys, the article suggests referring to guidelines on setting up and using API key access, with a specific link provided for further details on restricting access with API keys.
In summary, the article offers a comprehensive understanding of API keys and authentication in the context of Cloud Endpoints, providing valuable insights for developers and architects seeking to design secure and efficient API systems.
