SHA-256 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
- Enter text or drag a file to compute SHA-256 hash online.
- Click 'Generate SHA-256 Hash' for the 64-character hex result.
- Verify SHA256 checksums by entering the expected hash and comparing.
- Use for Bitcoin address verification, file integrity, or download verification.
- File input: Supports text files; for binary files, paste or upload as applicable.
2. How It Works
SHA-256 uses the Merkle–Damgård construction with 512-bit message blocks and a 256-bit state (eight 32-bit words a,b,c,d,e,f,g,h).
Message schedule: 16 input words expanded to 64: W[t]=σ₁(W[t-2])+W[t-7]+σ₀(W[t-15])+W[t-16], with σ₀(x)=ROTR(x,7)⊕ROTR(x,18)⊕SHR(x,3), σ₁(x)=ROTR(x,17)⊕ROTR(x,19)⊕SHR(x,10).
64 rounds with Ch, Maj, Σ₀, Σ₁ and round constants K[t] from cube roots of primes. Each round: T₁=h+Σ₁(e)+Ch(e,f,g)+K[t]+W[t]; T₂=Σ₀(a)+Maj(a,b,c); h=g; g=f; f=e; e=d+T₁; d=c; c=b; b=a; a=T₁+T₂.
Padding: append bit 1, then zeros so length≡448 (mod 512), then 64-bit length in bits. Output is the final state as eight 32-bit big-endian words (256 bits, 64 hex chars).
3. About SHA-256
SHA-256 is the industry-standard 256-bit hash function, part of the SHA-2 family. It was designed by the NSA and published in 2001.
This SHA-256 hash calculator computes hashes for text and files in your browser. SHA-256 is used in Bitcoin, TLS, SSL certificates, blockchain, and countless security applications.
SHA-256 is considered secure for most applications. No data leaves your device—all hashing is performed locally.
4. Advantages
- Industry standard: The most widely deployed cryptographic hash function.
- Security: No practical attacks on full SHA-256; suitable for most use cases.
- Bitcoin compatibility: SHA-256 is central to Bitcoin's proof-of-work and address derivation.
- Deterministic and fast: Same input always yields the same output; efficient implementation.
5. Real-World Use Cases
- File integrity: Verify downloads, backups, or software packages with SHA-256 checksums.
- Bitcoin and blockchain: SHA-256 powers Bitcoin mining and transaction hashing.
- Password hashing: Often used as the inner hash in PBKDF2 or HMAC.
- Digital signatures: Hash documents before signing with RSA or ECDSA.