Developer Tools
Generate a SHA-1 Hash
Sha1 Hash Generator for generating checksum or signature-style values from text.
Direct Answer
Use the SHA-1 Hash Generator for legacy compatibility, comparing against existing SHA-1 values, or non-adversarial checksums. SHA-1 is cryptographically broken for collision resistance and must not be used for passwords, signatures, or certificates.
Where SHA-1 still shows up
SHA-1 remains present in several long-running systems even though it's no longer recommended for new security work.
- Git's commit, tree, and blob object identifiers, historically based on SHA-1 for content addressing
- Older TLS certificates and legacy protocol handshakes that are being phased out industry-wide
- Legacy checksum fields carried over from older software and file formats
- Matching against pre-existing SHA-1 values already recorded in an older system you don't control
Why SHA-1 is not safe for security
SHA-1's collision resistance has been broken in practice, not just theory.
- The 2017 SHAttered attack by Google and CWI produced two different PDF files with the identical SHA-1 hash
- Major browsers and certificate authorities have deprecated and removed SHA-1 certificate support
- Never use SHA-1 for password hashing; use bcrypt, scrypt, or Argon2 instead
- Never use SHA-1 for digital signatures or certificate signing in new systems
- Use SHA-256 or a stronger algorithm for any new security-relevant hashing work
Specific Use Cases This Tool Handles
Common situations where this tool helps, and what to do in each.
| Use Case | How This Page Helps |
|---|---|
| Copy-ready variations | Generate several options, copy the best result, then regenerate when you need another batch. |
| Fast naming and content drafts | Use generated output as a starting point for captions, titles, names, snippets, or random values. |
| No account workflow | Run the generator in the browser without signing into a large creative suite. |
How to Use Sha1 Hash Generator
- Set your options (length, type, count) using the controls.
- Click Generate to produce new results.
- Click Copy next to any item to copy it individually, or Copy all to get everything.
- Download .txt saves all generated results as a text file.
- Click Generate again for a fresh set.
Reference
| Feature | Details |
|---|---|
| Purpose | Generate reusable output from selected options. |
| Input | Settings such as count, length, format, or topic. |
| Result | Generated items ready to copy. |
| Best for | Fast ideas, random values, names, passwords, codes, and reusable snippets. |
| Category | Developer Tools |
| Works on | Desktop, tablet, and mobile browsers |
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Frequently Asked Questions
Is SHA-1 safe to use for security purposes today?
No. SHA-1's collision resistance is broken in practice, not just theoretically. The 2017 SHAttered attack demonstrated two different files producing the identical SHA-1 hash, which is why it has been deprecated across browsers, certificate authorities, and most security standards.
How long is a SHA-1 hash?
A SHA-1 digest is 160 bits long, represented as 40 hexadecimal characters in its typical text form.
Why do git commit hashes look like SHA-1 hashes?
Git has historically used SHA-1 to generate object identifiers for commits, trees, and blobs, primarily for content-addressing and deduplication rather than as a security defense. Because of the same collision concerns that affect other uses of SHA-1, git has added support for a SHA-256 object format as an alternative.
What was the SHAttered attack?
SHAttered was a 2017 demonstration by researchers at Google and CWI Amsterdam that produced two visually different PDF files sharing the exact same SHA-1 hash. It proved that SHA-1 collisions are practically achievable with real computing resources, not just a theoretical weakness.
Can SHA-1 still be used safely for checking accidental file corruption?
Yes, for non-adversarial situations where no one is deliberately crafting a matching file, SHA-1 still works as a basic corruption check. That said, SHA-256 is a safer default going forward and performs nearly as fast on modern hardware, so there's little reason to keep choosing SHA-1 for new work.
Should I use SHA-1 for password hashing?
No. SHA-1 should never be used for password hashing. Like other general-purpose hash functions, it's fast to compute, which makes brute-force attacks practical, and it has no built-in salting. Use bcrypt, scrypt, or Argon2 for passwords instead.
Why do older SSL and TLS certificates reference SHA-1?
SHA-1 was the standard hash function used for certificate signatures for many years before its collision weaknesses became a practical concern. It has since been deprecated and removed from major browsers and certificate authorities, with SHA-256 now the standard.
Why does my SHA-1 hash differ from another tool's output for the same input?
This is usually a UTF-8 versus UTF-16 encoding mismatch before hashing, or a difference in trailing whitespace or a hidden newline character between the two versions of the input text.