SHA256 Hash Generator
The SHA-256 Hash Generator creates SHA-256 checksums from text input. SHA-256 is part of the SHA-2 family, designed by the NSA, and produces a 256-bit hash value displayed as a 64-character hexadecimal string. SHA-256 is currently considered secure and is widely used for digital signatures, certificate authorities, blockchain (Bitcoin), password hashing (with salt), file integrity verification, and SSL/TLS certificates. It is the recommended hash function for most security applications.
Formula
SHA-256 algorithm: - Input: any length message - Output: 256-bit (32-byte) hash - Displayed as: 64 hex characters - Block size: 512 bits - Rounds: 64 SHA-256 is a one-way function
Example
Input: Hello SHA-256: 185f8db32271fe25f561a6fc938b2e264306ec304eda518007d1764826381969 Input: Calczy SHA-256: a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2 Input: (empty string) SHA-256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
How to Use
- Enter or paste your text into the input field
- The SHA-256 hash is generated automatically
- Copy the 64-character hex string
- Use for digital signatures, file integrity, or security
- For passwords, use bcrypt or Argon2 instead
Frequently Asked Questions
Is SHA-256 secure?
Yes. SHA-256 is currently considered secure for all cryptographic applications. No practical collision attacks exist. It is used in SSL/TLS certificates, Bitcoin, digital signatures, and is recommended by NIST. It is the standard hash function for security.
Can SHA-256 be reversed?
No. SHA-256 is a one-way function. You cannot reverse a SHA-256 hash to get the original input. However, brute force and rainbow table attacks can find inputs that produce a given hash, especially for short or common inputs.
Should I use SHA-256 for password hashing?
SHA-256 alone is not ideal for passwords because it is too fast. Use bcrypt, scrypt, or Argon2 for passwords, which are designed to be slow and resistant to GPU attacks. If you must use SHA-256, use it with a salt and multiple iterations (PBKDF2).
How is SHA-256 used in Bitcoin?
Bitcoin uses SHA-256 for proof-of-work mining and address generation. Each block's hash is computed using SHA-256, and miners must find a hash below a target value. Bitcoin's security depends on the difficulty of reversing SHA-256.
What is the difference between SHA-256 and SHA-512?
SHA-256 produces 256-bit hashes (64 hex chars). SHA-512 produces 512-bit hashes (128 hex chars). SHA-512 is more secure but slower. For most applications, SHA-256 provides sufficient security. Both are part of the SHA-2 family.