Question 1

What is code integrity checking?

Accepted Answer

Code integrity checking is the practice of computing a cryptographic hash of your code at build time and verifying it at runtime. If the code has been modified (tampered with), the hashes won't match and your application can detect the modification and respond appropriately — such as refusing to run, logging a warning, or alerting an administrator.

Question 2

Which hash algorithm should I use?

Accepted Answer

For most applications, SHA-256 provides the best balance of security and performance. Use CRC32 or MD5 only for lightweight checks where speed is critical and tamper resistance is less important. SHA-1 is a reasonable middle ground. For maximum protection, combine multiple algorithms using the "Generate all algorithms" option.

Question 3

Can generated integrity checks be bypassed?

Accepted Answer

Skilled attackers can bypass runtime checks by patching the verification logic itself. To defend against this: use startup checks before any user code runs, split verification across multiple functions, and consider combining integrity checks with anti-debugging and obfuscation techniques. While no protection is absolute, multiple layers make bypassing significantly harder.

Question 4

What does the hash prefix mean?

Accepted Answer

The tool generates a hash prefix (typically the first 8-16 hex characters) rather than comparing the full hash. This is a common anti-reverse engineering technique — it reveals only part of the expected hash, making it harder for attackers to know the full expected value.

Question 5

Will integrity checks affect performance?

Accepted Answer

The performance impact depends on the algorithm and code size. CRC32 is extremely fast (microseconds). SHA-256 completes in milliseconds for typical functions. Startup checks run once so their impact is negligible. Inline checks can be optimized by only verifying critical code paths.

Question 6

What languages are supported?

Accepted Answer

JavaScript, TypeScript, Python, Java, C, C++, C#, Go, Rust, PHP, Ruby, and Swift. Each snippet uses the platform-native hash libraries.

Question 7

Is this tool completely free?

Accepted Answer

Yes — 100% free with no signup, no account, and no usage limits. All processing happens in your browser with no server calls. No premium tiers or rate limits.

Question 8

Can I customize the generated code?

Accepted Answer

Yes! The generated snippets are templates designed to be easily modified. You can change variable names, add custom error handling, integrate with your logging framework, and adapt to your specific security needs.

Code Integrity Checker Generator