Fine-grained access control in DynamoDB - Step-by-Step Execution

Concept Flow - Fine-grained access control

User Request

↓

Check User Identity

↓

Evaluate Access Policy

↓

Apply Filter/Condition

↓

Return Allowed Data Only

↓

Deny Unauthorized Access

When a user requests data, DynamoDB checks their identity, applies fine-grained policies, filters data accordingly, and returns only what the user is allowed to see.

Execution Sample

DynamoDB

SELECT * FROM Orders WHERE CustomerID = :userID
-- Access policy allows only orders of the requesting user

This query returns only the orders belonging to the user making the request, enforcing fine-grained access control.

Execution Table

Step	Action	Input	Policy Check	Result	Output
1	User sends request	Request for Orders table	N/A	N/A	Request received
2	Identify user	UserID = 123	N/A	User identified	UserID=123
3	Evaluate policy	Policy: access only own orders	UserID matches CustomerID?	Yes	Access granted for matching items
4	Apply filter	Orders data	Filter CustomerID = 123	Filtered data	Orders with CustomerID=123
5	Return data	Filtered orders	N/A	Data returned	Only user's orders sent
6	End	N/A	N/A	N/A	Request complete

💡 Execution stops after returning only the orders matching the user's ID, enforcing fine-grained access control.

Variable Tracker

Variable	Start	After Step 2	After Step 4	Final
UserID	N/A	123	123	123
Access Policy	Defined	Checked	Applied	Enforced
Data Returned	N/A	N/A	Filtered orders	Filtered orders

Key Moments - 2 Insights

Why does the system filter data after identifying the user?

Because the policy depends on the user's identity, filtering ensures only data allowed for that user is returned, as shown in execution_table step 4.

What happens if the user tries to access orders of another customer?

The policy check in step 3 fails, so no matching data passes the filter, resulting in no data returned, enforcing access control.

Visual Quiz - 3 Questions

Look at the execution table, what is the UserID after step 2?

A N/A

B 123

C 456

D Unknown

💡 Hint

Check the 'UserID' variable in variable_tracker after step 2.

At which step does the system apply the filter to return only allowed data?

A Step 2

B Step 3

C Step 4

D Step 5

💡 Hint

Look at the 'Apply filter' action in the execution_table.

If the policy allowed access to all orders, how would the output at step 4 change?

A All orders would be returned

B No orders would be returned

C Only user's orders would be returned

D An error would occur

💡 Hint

Consider the 'Apply filter' step and what happens if no filter is applied.

Concept Snapshot

Fine-grained access control in DynamoDB:
- Checks user identity on each request
- Applies policies to filter data per user
- Returns only authorized data
- Prevents unauthorized data access
- Uses conditions on attributes like CustomerID

Full Transcript

Fine-grained access control means DynamoDB checks who you are and only lets you see data you are allowed to see. When you ask for data, DynamoDB looks at your user ID, checks the rules, filters the data to only your items, and sends back just those. If you try to see someone else's data, it won't show it. This keeps data safe and private by controlling access at a detailed level.