Hash Generator — Online & Free
Compute MD5, SHA-1, SHA-256, and SHA-512 hashes for text and files. All processing happens in your browser — no data sent to any server.
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File to Hash
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Any file type, up to 50 MB. Processing happens in your browser.What Is a Hash Function?
A cryptographic hash function is a mathematical algorithm that maps data of arbitrary size to a fixed-size bit string (the hash value). The same input always produces the same output, but even a tiny change in the input creates a completely different hash. Hash functions are one-way — you cannot reverse a hash back to its original input.
Developers use hashes for password storage, file integrity verification, digital signatures, checksums, and blockchain operations. Different algorithms offer different trade-offs between speed and security.
Hash Algorithms Explained
MD5 (Message Digest 5) produces a 128-bit hash. It was once the most widely used hash algorithm, but cryptanalysts have demonstrated collision attacks — two different inputs can produce the same MD5 hash. MD5 is no longer recommended for security-sensitive applications like SSL certificates or digital signatures, but it remains useful for non-cryptographic purposes such as file checksums, data deduplication, and legacy system compatibility.
SHA-1 (Secure Hash Algorithm 1) produces a 160-bit hash. It improves on MD5 but has also been broken in practice — researchers have generated colliding PDF documents. Major browsers and operating systems have deprecated SHA-1 for certificate signing. Like MD5, it is acceptable for file verification where collision resistance is not critical, but SHA-256 is preferred for all new work.
SHA-256 (Secure Hash Algorithm 256-bit) is part of the SHA-2 family designed by the NSA. It produces a 256-bit hash and is currently considered secure against all known practical attacks. SHA-256 is the industry standard for password hashing (with salt), blockchain (Bitcoin uses it), TLS certificates, code signing, and software distribution checksums. If you need a hash for security purposes, use SHA-256.
SHA-512 produces a 512-bit hash, also part of the SHA-2 family. It offers a larger output size and operates on 64-bit words instead of 32-bit, making it potentially faster on 64-bit processors. SHA-512 is used in high-security environments and systems where maximum collision resistance is desired. The longer output also reduces the probability of accidental collisions to effectively zero.
Common Use Cases
- File integrity verification: Download a file from the internet along with its SHA-256 checksum. Recompute the hash after download to confirm the file was not corrupted or tampered with during transfer.
- Password storage: Store SHA-256 hashes of passwords (with unique salts) instead of plaintext passwords. Even if your database is breached, attackers cannot directly read user passwords.
- Data deduplication: Compute hashes of files or data blocks to quickly identify duplicates without comparing entire contents byte-by-byte.
- Digital signatures: Sign the hash of a document rather than the document itself. This is faster and produces a fixed-size signature regardless of document size.
- API request signing: Include a hash of request parameters and a secret key to verify that a request was not modified in transit.
- Cache invalidation: Use content hashes in filenames (e.g.,
app.a3f2b1.js) so CDNs and browsers cache immutable assets forever.
Frequently Asked Questions
Is this hash generator free?
Yes, completely free. No signup, no usage limits, no API calls. Everything runs in your browser.
Does this tool send my data to a server?
No. All hashing happens 100% client-side in your browser using JavaScript and the Web Crypto API. Your data never leaves your machine. This makes it safe for sensitive files, passwords, and proprietary data.
Which hash algorithm should I use?
For security-critical applications (passwords, digital signatures, certificates), use SHA-256 or SHA-512. For file checksums and integrity verification where collision attacks are not a concern, MD5 or SHA-1 are acceptable and often faster. Avoid MD5 and SHA-1 for anything involving adversaries who might try to forge data.
Can I hash files larger than 50 MB?
The file hasher works with files up to roughly 50 MB. Larger files may cause browser performance issues because the entire file is loaded into memory. For very large files, use a command-line tool like sha256sum on Linux, shasum -a 256 on macOS, or PowerShell on Windows.
Is hashing the same as encryption?
No. Hashing is a one-way function — you cannot recover the original data from the hash. Encryption is two-way — encrypted data can be decrypted back to its original form with the correct key. Use hashing for verification and encryption for confidentiality.
Can two different inputs produce the same hash?
In theory, yes — this is called a collision. Because hashes are fixed-size but inputs can be infinitely large, collisions must exist. However, for secure algorithms like SHA-256, finding a collision is computationally infeasible with current technology. For broken algorithms like MD5, collisions can be generated intentionally.