Ready to hash
Type or paste text, then click Generate Hash// generate sha-256 digest client-side, zero server contact
Generate SHA-256 hash digests instantly from text strings or files, entirely in your browser. No data is sent to any server.
Ready to hash
Type or paste text, then click Generate HashSelect Text, File, HMAC, or Compare tab depending on your use case.
Type text, drop a file, enter a message+key, or paste two hashes to compare.
Click Generate and copy the 64-character hex digest to your clipboard.
SHA-256 (Secure Hash Algorithm 256-bit) is a cryptographic hash function from the SHA-2 family. It maps any input to a fixed 256-bit (64 hex character) digest. This tool uses the Web Crypto API so all hashing happens locally — your data never leaves your browser.
No. All hashing is performed by your browser's built-in Web Crypto API. Your text and files never leave your device — there is zero network request for the hash computation.
A SHA-256 digest is always exactly 256 bits, represented as 64 hexadecimal characters (0–9, a–f). It does not matter how long or short your input is — the output is always 64 chars.
MD5 produces a 128-bit (32 hex char) digest and is considered cryptographically broken for security uses. SHA-256 produces a 256-bit (64 hex char) digest and is part of the SHA-2 family, which is still considered secure for most applications.
Yes. The file is read in chunks using JavaScript's FileReader API and streamed through the Web Crypto SubtleCrypto digest. Files up to several gigabytes can be hashed, though very large files may take a few seconds depending on your device.
HMAC (Hash-based Message Authentication Code) uses a secret key combined with the SHA-256 algorithm to produce an authentication code. It is used to verify both data integrity and authenticity — for example, signing webhook payloads or JWT tokens.
SHA-2 is the family name; SHA-256 is the specific variant with a 256-bit output. Other SHA-2 variants include SHA-224, SHA-384, and SHA-512. SHA-256 is by far the most widely deployed.
No. SHA-256 is a one-way function — it is computationally infeasible to reverse a hash back to the original input. This is by design, which is what makes it useful for data integrity and password hashing schemes.
SHA-256 is a deterministic algorithm — identical inputs always yield identical outputs. Even a single character difference produces a completely different 64-character hash. This property is called the avalanche effect.
SHA-256 is one of the most important cryptographic primitives in modern computing. Whether you are verifying a downloaded file's integrity, signing an API request, or studying how cryptographic hash functions behave, having a fast and trustworthy SHA-256 hasher in your browser is invaluable. This tool generates SHA-256 digests entirely within your browser using the Web Crypto API — no data is ever sent to a remote server.
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SHA-256 stands for Secure Hash Algorithm, 256-bit. It was designed by the National Security Agency (NSA) and published by NIST in 2001 as part of the SHA-2 family. A hash function takes an input of arbitrary length and returns a fixed-length output — in SHA-256's case, always 256 bits (32 bytes), rendered as a 64-character hexadecimal string.
The key properties that make SHA-256 cryptographically useful are:
The tool has four modes, each designed for a common workflow:
SHA-256 appears in many layers of the modern web and software ecosystem:
<script> and <link> tags can include a SHA-256 integrity attribute. Browsers refuse to execute or apply the resource if it does not match the specified hash.Different situations call for different hash algorithms. Here is a quick comparison:
HMAC stands for Hash-based Message Authentication Code. Where a plain SHA-256 hash only verifies integrity (the data has not changed), an HMAC also verifies authenticity (the message came from someone who knows the secret key). The construction is:
HMAC(key, message) = SHA256((key XOR opad) || SHA256((key XOR ipad) || message))
In practice, you share a secret key with the recipient out-of-band. When sending a message, you compute HMAC-SHA256 of the payload with the key and include the result as a signature. The recipient re-computes the HMAC independently and compares — if they match, the message is authentic and untampered. This is exactly how GitHub Webhook signatures, Stripe event signatures, and AWS request signing work.
SHA-256 is considered secure against all known attacks as of 2025. The best known attack against SHA-256 reduces the security margin slightly in theoretical analysis but provides no practical threat. NIST recommends SHA-256 for all general-purpose security applications through at least 2030. For long-lived data requiring protection decades into the future, SHA-384 or SHA-512 provides additional margin.
Remember that SHA-256 is not suitable for direct password storage — use bcrypt, scrypt, or Argon2 for passwords, as these are deliberately slow to resist brute-force attacks. SHA-256 is designed to be fast, which is a vulnerability when hashing low-entropy inputs like passwords.