Is it safe to hash files here?

Yes. Files are read in your browser with the FileReader API and hashed locally with the Web Crypto API. Nothing is uploaded to any server.

Can I hash passwords with this tool?

You can, but you shouldn't store raw hashes for passwords. Use a dedicated key-derivation function such as bcrypt, scrypt, or Argon2, which add salting and work factors.

An HMAC (Hash-based Message Authentication Code) combines a secret key with a message using a hash function to prove both integrity and authenticity, commonly used to sign API requests and webhooks.

Hash Generator — MD5, SHA-256 & HMAC Online

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Walk-through

How to Use This Calculator

4 steps

1

Pick a mode

Choose Text Hash to hash a string, File Hash to fingerprint a file, Compare / Verify to check a download against a published checksum, or HMAC to sign a message with a secret key. The mode tabs sit right under the title.

2

Enter your data

Type or paste text, or drag a file onto the drop zone. Files are read locally with the browser's FileReader and hashed with the Web Crypto API — nothing is ever uploaded. Try one of the example chips to see known values instantly.

3

Choose algorithms and format

Tick the algorithms you need (MD5, SHA-1, SHA-256, SHA-384, SHA-512). Switch the output between lowercase or uppercase hex and Base64 using the toggles at the top. Each algorithm renders on its own row.

4

Copy, export, or verify

Copy any single hash, copy all of them at once, or export the set as CSV. In Compare / Verify mode, paste the expected hash and the tool shows a clear MATCH or NO MATCH verdict.

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Reference

Formula & Methodology

3 formulas

What a hash function does

digest = H(message)

A cryptographic hash function H maps a message of any length to a fixed-length digest (128 bits for MD5, 256 for SHA-256, 512 for SHA-512). The same input always produces the same digest, but the digest reveals nothing about the input and cannot be reversed.

The avalanche effect

H(x) vs H(x + 1 bit) → ~50% of output bits flip

A good hash function is designed so that changing a single bit of the input changes roughly half of the output bits. That is why the visual fingerprint in this tool changes completely whenever you edit even one character — and why hashes are useful for detecting tampering.

HMAC construction

HMAC(K, m) = H((K ⊕ opad) ‖ H((K ⊕ ipad) ‖ m))

An HMAC mixes a secret key K into the message m using two padded passes through the hash function H (with the inner pad ipad = 0x36 repeated and outer pad opad = 0x5c repeated). Without the key, an attacker cannot forge a valid HMAC, which is why APIs use it to authenticate requests.

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Glossary

Key Terms Explained

10 terms

Hash function A one-way function that turns input of any size into a fixed-length string (the digest). Designed to be fast to compute, impossible to reverse, and collision-resistant.

Digest The fixed-length output of a hash function, usually shown as hexadecimal or Base64. SHA-256 produces a 256-bit (64-hex-character) digest.

Checksum A hash used to verify that a file downloaded or transferred without corruption. Publishers post the expected checksum so you can confirm your copy matches byte-for-byte.

Collision Two different inputs that produce the same hash. A secure hash makes finding one computationally infeasible. MD5 and SHA-1 are 'broken' precisely because practical collisions have been demonstrated.

MD5 A 128-bit hash from 1991. Extremely fast but cryptographically broken — usable only for non-security checksums and deduplication, never for signatures or passwords.

SHA-2 The Secure Hash Algorithm 2 family (SHA-256, SHA-384, SHA-512). The current workhorse for integrity checks and digital signatures, with no known practical collisions.

HMAC Hash-based Message Authentication Code. Combines a secret key with a message so the recipient can verify both that the message is intact and that it came from someone holding the key.

Salt Random data added to an input before hashing so identical inputs produce different digests. Essential for password storage to defeat precomputed 'rainbow table' attacks.

Hexadecimal (hex) Base-16 encoding using 0-9 and a-f. Each byte becomes two hex characters, so a 32-byte SHA-256 digest is 64 hex characters long.

Base64 A text encoding that represents binary data using 64 ASCII characters. More compact than hex (about 33% shorter) and case-sensitive, so it is never uppercased.

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Scenarios

Real-World Examples

3 worked examples

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Maya — verifying a Linux ISO download

Maya downloads a 2 GB Ubuntu ISO and the project's website lists a SHA-256 checksum. She opens the File Hash tab, drops the ISO in, and the SHA-256 digest is computed locally. Then she switches to Compare / Verify, chooses File as the source, picks SHA-256, and pastes the published checksum.

Mode File Hash → Compare / Verify Algorithm SHA-256 Expected published checksum

The tool shows ✓ MATCH, confirming the download is bit-for-bit identical to what the publisher released — no corruption in transit and no tampering. If it had shown ✗ NO MATCH, she would re-download before running the installer.

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Dev team — signing a webhook payload

An engineering team needs to authenticate outgoing webhooks. They share a secret key with the receiver and sign each JSON payload with HMAC-SHA-256. In the HMAC tab they enter the key and the exact request body, then read the hex signature.

Algorithm HMAC-SHA-256 Secret key shared API secret Message raw JSON body

The receiver recomputes the HMAC with the same key and compares it to the signature header. Because only the two parties know the key, a matching HMAC proves the payload is authentic and unmodified — this is exactly how Stripe, GitHub, and Slack verify webhooks.

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Priya — why MD5 is wrong for passwords

Priya is reviewing a legacy app that stores user passwords as raw MD5 hashes. She hashes the string 'password' with MD5 and SHA-256 to compare, then explains the risk to the team.

Mode Text Hash Input password Algorithms MD5, SHA-256

Both produce a digest instantly — and that speed is the problem. MD5 is so fast that an attacker can try billions of guesses per second, and the MD5 of common passwords is already in public lookup tables. The fix is not 'switch to SHA-256' but to use a deliberately slow, salted key-derivation function such as bcrypt, scrypt, or Argon2.

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Deep Dive

Hashing Explained: Checksums, Security, and HMACs

4 chapters · 5 min read

A hash function turns any input — a word, a document, a 4 GB disk image — into a short, fixed-length fingerprint. This tool computes the common ones (MD5, SHA-1, SHA-256, SHA-384, SHA-512) and builds HMACs, all in your browser. This guide explains what hashes are good for, which ones are safe in 2026, and the difference between hashing, encryption, and password storage.

What hashes are actually for

Hashing has two everyday jobs: integrity and identification. When you download software and check its SHA-256 against the publisher's posted value, you are confirming the bytes arrived intact. When a Git commit, a content-addressed cache, or a deduplication system needs a short stable ID for a blob of data, a hash provides it. The defining property is determinism: the same input always yields the same digest, and any change — one flipped bit — produces a completely different one (the avalanche effect you can watch in the fingerprint above).

Which algorithms are safe in 2026

MD5 (1991) and SHA-1 (1995) are cryptographically broken: researchers have produced real collisions (two different files with the same hash), so they must never be used where an attacker could benefit from forging a match — signatures, certificates, tamper detection. They remain fine for non-adversarial checksums like detecting accidental corruption or deduplicating files.

The SHA-2 family — SHA-256, SHA-384, and SHA-512 — has no known practical collisions and is the right default for anything security-sensitive. SHA-512 is often faster than SHA-256 on 64-bit hardware, so 'bigger' does not mean 'slower' here.

Hashing is not encryption — and not password storage

Encryption is reversible with a key; hashing is one-way by design, so there is no 'unhash.' That makes hashes useless for confidentiality but ideal for verification.

Passwords are a special case. Raw fast hashes (even SHA-256) are a poor choice because their speed lets attackers test billions of guesses per second against a stolen database. Modern password storage uses a key-derivation function — bcrypt, scrypt, or Argon2 — that is deliberately slow and adds a per-user salt. If you are hashing passwords, reach for one of those, not the algorithms in this tool.

HMAC: proving who sent a message

A plain hash proves a message was not changed, but anyone can recompute it — so it cannot prove who sent the message. An HMAC fixes that by folding a shared secret key into the hash. The sender computes HMAC(key, message) and attaches it; the receiver recomputes it with the same key. A match proves both integrity and authenticity. This is the mechanism behind webhook signatures (Stripe, GitHub, Slack), AWS request signing, and JWT 'HS256' tokens. Use a long, random key and compare HMACs with a constant-time check on the server side.

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Questions

Frequently Asked Questions

7 questions

Is it safe to hash files and text here?+

Yes. Everything runs locally in your browser — text is hashed in memory and files are read with the FileReader API and hashed with the Web Crypto API. No text, file, or key is ever sent to a server, which is why this tool works even with your network disconnected.

Should I use MD5 or SHA-1 for security?+

No. Both are cryptographically broken — practical collisions exist, meaning an attacker can craft two different inputs with the same hash. Use them only for non-security checksums (detecting accidental corruption, deduplication). For integrity that an attacker might attack, or for any signature, use SHA-256 or stronger.

Can I use this to hash passwords?+

You can compute the hash, but you should not store passwords as raw hashes — not even SHA-256. Fast hashes let attackers guess billions of passwords per second. Use a purpose-built, salted, slow key-derivation function such as bcrypt, scrypt, or Argon2 instead.

What is the difference between hex and Base64 output?+

They encode the same bytes differently. Hex uses 0-9 and a-f, two characters per byte, and is case-insensitive. Base64 uses 64 characters, is about 33% shorter, and is case-sensitive (so this tool never uppercases it). Most published checksums are hex; some APIs prefer Base64.

Why does the fingerprint change completely when I edit one character?+

That is the avalanche effect, a deliberate design goal of cryptographic hashes: changing a single input bit flips about half of the output bits. It is what makes hashes reliable for detecting tampering — even a tiny change is unmissable.

What is an HMAC and when do I need one?+

An HMAC (Hash-based Message Authentication Code) mixes a secret key into a hash so the recipient can verify both that a message is unchanged and that it came from someone who holds the key. It is used to sign API requests and verify webhooks. A plain hash only proves integrity; an HMAC also proves authenticity.

Why do MD5 and SHA-256 of the same text look totally different lengths?+

Each algorithm has a fixed output size regardless of input: MD5 is 128 bits (32 hex characters), SHA-1 is 160 bits (40 characters), SHA-256 is 256 bits (64 characters), and SHA-512 is 512 bits (128 characters). Longer digests leave less room for collisions.

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Hash Generator