What is SHA-256 and how does it work?

SHA-256 is a cryptographic hash function that accepts input of any length and outputs a fixed 256-bit digest, typically displayed as 64 hexadecimal characters. Small input changes produce very different outputs.

Can I reverse a SHA-256 hash to get the original text?

No. SHA-256 is designed as a one-way function. You cannot decrypt a hash back to the original input. Matching a target hash requires guessing inputs and re-hashing them.

What are common use cases for SHA-256 hashes?

Typical uses include file integrity verification, digital signatures, SSL/TLS certificates, blockchain systems, Git object hashing, and HMAC authentication. For password storage, use Argon2, bcrypt, scrypt, or PBKDF2 instead of plain SHA.

Is SHA-256 still considered secure?

SHA-256 is currently considered secure for integrity and signature workflows, with no known practical collision or preimage attacks. For password hashing, use dedicated password hashing algorithms such as Argon2, bcrypt, scrypt, or PBKDF2.

Hash Generator

Generate SHA-1, SHA-256, and SHA-512 hashes of text in your browser.

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Result

About Hash Generator

This hash generator computes cryptographic digests using SHA-1, SHA-256, and SHA-512 algorithms entirely in your browser using the Web Crypto API. No data is sent to any server.

Last reviewed: March 27, 2026.

Hash Algorithm Overview

Algorithm	Hash Size	Hex Length	Security	Use Case
`SHA-1`	160 bits	40 chars	Deprecated	Legacy systems
`SHA-256`	256 bits	64 chars	Secure	Recommended
`SHA-512`	512 bits	128 chars	Secure	High security margins

Hash Examples (Input: "Hello, World!")

SHA-1:   0a0a9f2a6772942557ab5355d76af442f8f65e01
SHA-256: dffd6021bb2bd5b0af676290809ec3a53191dd81c7f70a4b28688a362182986f
SHA-512: 374d794a95cdcfd8b35993185fef9ba368f160d8daf432d08ba9f1ed1e5abe6cc69291e0fa2fe0006a52570ef18c19def4e617c33ce52ef0a6e5fbe318cb0387

Key Properties of Cryptographic Hashes

Deterministic: Same input always produces the same hash
One-way: Cannot reverse the hash to recover the original input
Avalanche effect: Tiny input changes produce dramatically different hashes
Fixed output: Each algorithm always produces the same size output
Collision resistant: Extremely difficult to find two inputs with the same hash

Common Use Cases

File Integrity: Verify downloaded files match expected SHA checksums
HMAC Authentication: Build message authentication codes with SHA-256/SHA-512
Digital Signatures: Sign documents and verify authenticity (SHA-256, SHA-512)
Blockchain: Bitcoin uses SHA-256 for mining and transactions
SSL/TLS: Secure web certificates use SHA-256 for signing
Git: Uses SHA-1 (transitioning to SHA-256) for commit hashing
Data Deduplication: Identify duplicate files by comparing hashes

Security Recommendations

For passwords: Use Argon2, bcrypt, scrypt, or PBKDF2 with unique salts (not plain SHA)
For new projects: Use SHA-256 or SHA-512
Avoid MD5/SHA-1: For any security-sensitive applications
Verify sources: Always get reference hashes from trusted sources

Standards and References

How to Generate SHA-256 Hashes

Enter your text: Type or paste the text you want to hash into the input box.
Click SHA-256: The tool computes the digest using your browser's Web Crypto API.
Review the hash: The 64-character hexadecimal hash appears in the output box.
Copy the result: Click "Copy Result" to copy the hash to your clipboard.

Try These Examples

Test the tool with known inputs to verify correctness:

Empty string → e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
"abc" → ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad
"The quick brown fox jumps over the lazy dog" → d7a8fbb307d7809469ca9abcb0082e4f8d5651e46d3cdb762d02d0bf37c9e592

Frequently Asked Questions

What is SHA-256 and how does it work?: SHA-256 (Secure Hash Algorithm 256-bit) is a cryptographic hash function that takes any input and produces a fixed 256-bit (32-byte) output, typically displayed as 64 hexadecimal characters. It processes data in 512-bit blocks through 64 rounds of mathematical operations, producing a unique fingerprint that changes dramatically with even tiny input modifications.
Can I reverse a SHA-256 hash to get the original text?: No. SHA-256 is a one-way function by design. You cannot decrypt or reverse a hash to recover the original input. The only way to find the original text is through brute-force guessing (trying many inputs until one produces the same hash), which is computationally infeasible for complex inputs.
What are common use cases for SHA-256 hashes?: Common SHA-256 use cases include file integrity verification, digital signatures, blockchain/cryptocurrency systems, SSL/TLS certificates, Git object hashing, and HMAC authentication. For password storage, use dedicated password hashing functions such as Argon2, bcrypt, scrypt, or PBKDF2.
Is SHA-256 still considered secure?: Yes. SHA-256 is currently considered secure for integrity and signature workflows, with no known practical collision or preimage attacks. This page was last reviewed on March 27, 2026. For password hashing specifically, use dedicated functions like Argon2, bcrypt, scrypt, or PBKDF2 with proper salting.
What is the difference between SHA-256 and other hash algorithms?: SHA-256 produces a 256-bit hash and is part of the SHA-2 family. MD5 (128-bit) and SHA-1 (160-bit) are considered broken due to collision attacks. SHA-3 uses a different internal structure (Keccak) but provides similar security. SHA-512 produces a longer 512-bit hash for higher security requirements.
Why does my hash differ from an online generator?: Common causes include: different input encoding (UTF-8 vs ASCII), extra whitespace or newlines in the input, or using a different hash algorithm. Ensure you're comparing the exact same input text and algorithm. This tool uses UTF-8 encoding via the Web Crypto API.