SHA-256 Hash
Generate SHA-256 hashes from text in your browserInput
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About SHA-256 Hash
Generate SHA-256 hashes for passwords, checksums, and data integrity verification. Runs via the Web Crypto API entirely in your browser — your input never reaches any server.
Frequently Asked Questions
What is SHA-256?
SHA-256 is a cryptographic hash function from the SHA-2 family that produces a 64-character hexadecimal digest from any input. It is collision-resistant and pre-image resistant, making it suitable for digital signatures, TLS certificates, and data integrity verification.
Can a SHA-256 hash be reversed or decrypted?
No. SHA-256 is a one-way function by design — there is no algorithm to recover the original input from the hash. For short or common inputs (passwords, dictionary words), precomputed rainbow tables exist. For arbitrary data of meaningful length (documents, files), reversal is computationally infeasible. SHA-256 is not encryption — use AES or RSA to encrypt data you need to recover.
What is the difference between SHA-256 and SHA-512?
SHA-256 produces a 256-bit (32-byte) hash; SHA-512 produces a 512-bit (64-byte) hash. SHA-512 is marginally more collision-resistant and may be faster on 64-bit hardware due to its internal 64-bit word operations. SHA-256 is the standard choice for TLS certificates, code signing, and blockchain. Both are considered cryptographically secure.
What is SHA-256 used for in practice?
SHA-256 is used in TLS/HTTPS certificate signatures, code signing (Authenticode, macOS Gatekeeper), Bitcoin proof-of-work, Git commit hashes (Git switched from SHA-1 to SHA-256), HMAC-SHA256 for API authentication, and data integrity verification for downloads and archives.
Why does the same file always produce the same SHA-256 hash?
SHA-256 is deterministic — the output depends only on the input bytes. Even one changed byte produces a completely different hash (the avalanche effect). This property makes SHA-256 useful for detecting file corruption, verifying downloads, and detecting tampered data: compare the hash before and after transmission.