SHA-1 Hash Calculator
hash
All hashing runs in your browser. Data is never sent to any server.
Text Input
File Input
Drag & drop a file or click to select
1. How to Use
- Paste text or upload a file to generate SHA-1 hash online.
- Click 'Generate SHA-1 Hash' to get the 40-character hexadecimal result.
- Verify SHA1 checksums by pasting the expected hash and comparing with new input.
- Use for Git hash verification or SHA1 checksum comparison.
- File support: Drag-and-drop or select files for SHA-1 computation.
2. How It Works
SHA-1 also uses the Merkle–Damgård construction with 512-bit blocks and a 160-bit state (five 32-bit words A,B,C,D,E).
The message schedule extends 16 words to 80 words: W[t] = ROL(W[t-3]⊕W[t-8]⊕W[t-14]⊕W[t-16], 1) for t≥16.
Four round functions and constants: f₀,f₁,f₂,f₃ with K₀=0x5A827999, K₁=0x6ED9EBA1, K₂=0x8F1BBCDC, K₃=0xCA62C1D6. Each of 80 rounds: T=ROL(A,5)+fₜ(B,C,D)+E+W[t]+Kₜ; E=D; D=C; C=ROL(B,30); B=A; A=T.
Initial hash values are the first five primes; final output is 160 bits (40 hex characters).
3. About SHA-1
SHA-1 (Secure Hash Algorithm 1) is a 160-bit hash function developed by the NSA and standardized by NIST in 1995.
This SHA-1 hash calculator computes SHA1 hashes for text and files in your browser. SHA-1 is used in Git commit hashes, TLS certificates (legacy), and various checksum applications.
SHA-1 is cryptographically broken—collision attacks are practical. It remains in use for Git and legacy compatibility but should not be used for new security-sensitive designs.
4. Advantages
- Git compatibility: Git uses SHA-1 for commit and object IDs; this tool helps verify or explore Git hashes.
- Legacy support: Many existing systems and certificates still use SHA-1.
- Deterministic: Same input always produces the same SHA-1 hash.
- Privacy-first: All hashing runs locally in your browser.
5. Real-World Use Cases
- Git object verification: Check Git commit hashes, blob hashes, or tree hashes.
- Legacy TLS/SSL: Inspect SHA-1 fingerprints for older certificates.
- Checksum validation: Verify file integrity where SHA-1 is the published checksum.
- Compatibility testing: Ensure your application produces correct SHA-1 hashes.