Signed URLs for temporary access in GCP - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

How does a Signed URL provide temporary access?

Which statement best explains how a Signed URL grants temporary access to a resource in Google Cloud Storage?

A It embeds a cryptographic signature and expiration time in the URL, allowing access only until the expiration.

B It sends an email with a password to access the resource temporarily.

C It changes the resource's permissions to public for a limited time.

D It creates a new user account with limited permissions for a short time.

💡 Hint

Think about how the URL itself controls access without changing user accounts or permissions.

A Signed URL includes a cryptographic signature and an expiration timestamp. This allows anyone with the URL to access the resource only until the expiration time, without changing the resource's permissions or creating new users.

❓ Configuration

intermediate

Expiration time in Signed URLs

You create a Signed URL with an expiration time set to 10 minutes from now. What happens if a user tries to access the URL after 15 minutes?

A The resource becomes publicly accessible permanently.

B The access is allowed because the URL is still valid.

C The access is denied because the Signed URL has expired.

D The URL automatically renews the expiration time.

💡 Hint

Consider what the expiration time controls in a Signed URL.

Once the expiration time passes, the Signed URL is no longer valid, and access is denied to protect the resource.

❓ Architecture

advanced

Best practice for distributing Signed URLs securely

You want to share a Signed URL with a client securely. Which method is the best practice to distribute the Signed URL?

A Post the Signed URL publicly on a website.

B Send the Signed URL over an encrypted channel like HTTPS or secure email.

C Send the Signed URL via plain text SMS.

D Embed the Signed URL in a public GitHub repository.

💡 Hint

Think about how to keep the URL secret to prevent unauthorized access.

Signed URLs grant access to resources, so sharing them over secure, encrypted channels prevents interception by unauthorized users.

❓ service_behavior

advanced

Effect of changing object permissions after Signed URL creation

You create a Signed URL for a private object in Cloud Storage. After creating the URL, you change the object's permissions to public. What happens when someone uses the Signed URL?

A The Signed URL still works until it expires, but the object is also accessible publicly without the URL.

B The Signed URL expires immediately when permissions change.

C The Signed URL stops working immediately after permissions change.

D The Signed URL grants access only if the object remains private.

💡 Hint

Consider how Signed URLs and object permissions interact.

Changing the object to public makes it accessible to anyone, regardless of the Signed URL. The Signed URL remains valid until its expiration.

❓ security

expert

Security risk of long expiration times in Signed URLs

What is the main security risk of setting a very long expiration time (e.g., several months) on a Signed URL?

A Long expiration times cause the resource to become publicly listed in Cloud Storage.

B The URL will automatically revoke access after 24 hours regardless of expiration time.

C Signed URLs with long expiration times consume more storage space.

D If the URL is leaked, unauthorized users can access the resource for a long time.

💡 Hint

Think about what happens if someone else gets the URL.

Long expiration times increase the window during which a leaked Signed URL can be misused, risking unauthorized access.