Hash Generator
Generate cryptographic hashes using your browser's native SubtleCrypto API. Zero network requests — your data stays local.
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Cryptographic Hash Functions
Hash Function Properties (One-Way)
A cryptographic hash function is a one-way mathematical function that maps data of arbitrary size to a fixed-size bit string (the "hash" or "digest"). The SHA-2 family (SHA-256, SHA-384, SHA-512) is defined in FIPS 180-4 and is widely used in TLS certificates, code signing, and password hashing.
SHA Algorithm Comparison
| Algorithm | Output (bits) | Block Size | Status | Use Case |
|---|---|---|---|---|
| SHA-1 | 160 | 512 bits | ⚠️ Deprecated | Legacy only — CVE-2017-15361 |
| SHA-256 | 256 | 512 bits | ✅ Secure | TLS, GPG, Bitcoin, JWT |
| SHA-384 | 384 | 1024 bits | ✅ Secure | TLS 1.3, ECDSA P-384 |
| SHA-512 | 512 | 1024 bits | ✅ Secure | Password hashing, archival |
| SHA-3/256 | 256 | 1088 bits | ✅ Secure | Quantum-resistant alternative |
Key Properties of Hash Functions
- Deterministic: The same input always produces the same hash output.
- One-Way (Pre-image Resistant): It is computationally infeasible to reverse a hash back to its original input.
- Avalanche Effect: A single bit change in the input completely changes the output hash.
- Collision Resistant: It is computationally infeasible to find two different inputs with the same hash.
- Fixed Output Size: Regardless of input size, SHA-256 always produces a 256-bit (32-byte) output.
⚠️ SHA-1 is Broken
SHA-1 collision attacks have been demonstrated (SHAttered, 2017). Do not use SHA-1 for digital signatures, certificates, or security-sensitive applications. Use SHA-256 or higher.
Frequently Asked Questions
Which hash algorithm should I use — SHA-256 or SHA-1?
SHA-256 (or stronger) is recommended for anything security-sensitive. SHA-1 is considered cryptographically broken for collision resistance and should only be used for legacy compatibility or non-security checksums, not for passwords or integrity-critical data.
Can I reverse a hash back to the original text?
No — cryptographic hash functions are one-way by design. You can only verify a match by hashing the same input again and comparing the output, which is exactly how password verification systems work.
Why does hashing the same text always give the same result?
Hash functions are deterministic — the same input always produces the same output, which is what makes them useful for verifying file integrity or detecting duplicate content.
Is this tool safe for hashing sensitive data?
Yes — it uses your browser's native SubtleCrypto API to compute hashes locally; your input text never leaves your device or gets sent to any server.
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