Question 1

What is a hash?

Accepted Answer

A cryptographic hash function takes any input (text, file, data) and produces a fixed-length string of characters. The same input always produces the same hash, but even a single character change produces a completely different hash. You cannot reverse a hash to get back the original input.

Question 2

What is SHA-256 used for?

Accepted Answer

SHA-256 is the current standard for most security applications: verifying file downloads, digital signatures, certificate authorities, blockchain (Bitcoin uses SHA-256), and password hashing (via bcrypt or Argon2 which internally use SHA). It is considered cryptographically secure against all currently known attacks.

Question 3

Why is MD5 deprecated for security?

Accepted Answer

MD5 was broken in 2004 when researchers demonstrated collision attacks — two different inputs that produce the same hash. An attacker can craft a malicious file that has the same MD5 as a legitimate file. Use SHA-256 for any security-critical purpose. MD5 is still fine for checksums where security is not required, such as detecting accidental file corruption.

Question 4

How does file integrity verification work?

Accepted Answer

When you download software, the publisher often provides a SHA-256 hash of the file. Upload the downloaded file, compute its SHA-256 hash, and compare it to the published hash. If they match exactly, the file is identical to what the publisher released and was not modified or corrupted in transit.

Question 5

Is my file or text sent to a server?

Accepted Answer

No. All hashing runs in your browser. SHA hashes use the Web Crypto API (crypto.subtle.digest), which is a browser built-in. MD5 uses a pure JavaScript implementation. Nothing is transmitted anywhere — your files and text stay entirely on your device.

Hash Generator

Verify file integrity

How it works

Why Criply

Frequently asked questions

Related tools