DP-300 Implement a secure environment Practice Question
Your company uses Azure SQL Database and needs to protect sensitive columns (e.g., credit card numbers) from being accessed by unauthorized users. You implement Always Encrypted. However, some queries that perform pattern matching on the encrypted column are failing because the column cannot be searched. What should you do to allow pattern matching while maintaining security?
⚠ Common exam trap
Test-takers frequently confuse deterministic encryption (which enables equality) with the ability to perform pattern matching, or they mistakenly think Dynamic Data Masking or row-level security can substitute for encrypted search capabilities.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Enable Always Encrypted with secure enclaves and use a column master key that supports enclave computations.
Always Encrypted with secure enclaves allows computations, including pattern matching (LIKE, equality, comparisons), on encrypted columns by using a trusted execution environment (e.g., Intel SGX). The column master key must support enclave computations (enclave-enabled key) to permit the SQL Server engine to offload operations to the enclave. This preserves encryption at rest and in transit while enabling rich query patterns.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Enable Always Encrypted with secure enclaves and use a column master key that supports enclave computations.
Why this is correct
Deterministic encryption only permits equality comparisons, so pattern matching fails. Secure enclaves extend Always Encrypted by performing computations inside a hardware-protected enclave, enabling `LIKE`, range and sorting operations on encrypted columns. Configuring an enclave-enabled column master key satisfies the stem's requirement to search encrypted data while keeping it protected from unauthorised users.
- ✗
Implement row-level security (RLS) to filter rows based on user identity.
Why it's wrong here
RLS filters which rows a user may retrieve based on predicates; it does not alter column encryption, so pattern matching on the Always Encrypted column still fails. It is tempting because RLS restricts data access by identity, and would be correct when the requirement is row-level authorisation rather than column confidentiality.
- ✗
Change the encryption type from randomized to deterministic encryption.
Why it's wrong here
Deterministic encryption permits equality comparisons only; LIKE pattern matching remains unsupported because ciphertext preserves no ordering or substring structure. It is tempting because deterministic encryption enables joins and point lookups on encrypted columns, and would be correct when exact-match querying, not pattern matching, is required.
- ✗
Use Dynamic Data Masking (DDM) to mask the column for unauthorized users instead of encryption.
Why it's wrong here
DDM only obfuscates values in query results for non-privileged users; the data remains plaintext at rest, so it neither encrypts the column nor enables pattern matching on encrypted data. It is tempting because DDM restricts unauthorised viewing cheaply, and would suit scenarios needing display masking without cryptographic protection.
Go deeper
Related to this question
Learn chapter
Securing Data at Rest and in Transit
Key term
Azure SQL Performance Tuning
Azure SQL Performance Tuning is the process of optimizing the speed and efficiency of queries and database operations in Microsoft Azure SQL Database or SQL Managed Instance to reduce latency and improve throughput.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DP-300 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DP-300 exam.