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SHA-1 Hash Generator

Generate SHA-1 (160-bit) cryptographic hash from any text

Security Notice

SHA-1 is considered cryptographically weak and should not be used for security-critical applications. While stronger than MD5, it's vulnerable to collision attacks and has been deprecated by major security standards. Use SHA-256 or SHA-3 for modern applications.

About SHA-1

SHA-1 (Secure Hash Algorithm 1) is a cryptographic hash function that produces a 160-bit (20-byte) hash value, typically rendered as a 40-character hexadecimal number. It was designed by the NSA and published in 1995.

Limited Use Cases:

  • Git version control (commit hashes)
  • Legacy system compatibility
  • Non-security file verification
  • Backward compatibility requirements

Security Concerns:

  • Practical collision attacks demonstrated in 2017
  • Deprecated by NIST since 2011 for digital signatures
  • Major browsers no longer trust SHA-1 certificates
  • Not recommended for password hashing or new applications

Technical Details:

  • Output: 160 bits (40 hexadecimal characters)
  • Block size: 512 bits
  • Rounds: 80
  • Designed by: NSA (1995)

For modern security needs, migrate to SHA-256, SHA-3, or bcrypt/Argon2 for passwords.

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SHA-1 Hash Generator: Create SHA-1 Hashes Online

Generate SHA-1 hashes instantly with our free online SHA-1 hash generator. SHA-1 (Secure Hash Algorithm 1) produces a 160-bit hash value displayed as a 40-character hexadecimal string. While deprecated for security applications due to collision vulnerabilities, SHA-1 remains in use for Git version control and legacy system compatibility.

Understanding SHA-1

SHA-1 was designed by the NSA and published in 1995 as part of the Secure Hash Algorithm family. It processes data in 512-bit blocks through 80 rounds of operations to produce a 160-bit hash. While more secure than MD5, practical collision attacks demonstrated in 2017 proved SHA-1 is no longer suitable for cryptographic security.

Current SHA-1 Use Cases

  • Git Version Control: Git uses SHA-1 for commit hashes and object identification
  • Legacy Systems: Older applications that haven't migrated to newer algorithms
  • File Verification: Non-security checksums for file integrity
  • Backward Compatibility: Systems requiring SHA-1 for compatibility

SHA-1 Security Timeline

NIST deprecated SHA-1 for digital signatures in 2011. In 2017, Google and CWI Amsterdam demonstrated the first practical collision attack (SHAttered), proving two different files could produce identical SHA-1 hashes. Major browsers stopped trusting SHA-1 certificates in 2017. For any new security applications, use SHA-256 or stronger algorithms.

Frequently Asked Questions

Is SHA-1 still safe to use?

Not for security purposes. SHA-1 is vulnerable to collision attacks and should not be used for passwords, digital signatures, or certificates. Use SHA-256 or SHA-3 instead.

Why does Git still use SHA-1?

Git's use case doesn't require collision resistance in the same way as certificates. Git is transitioning to SHA-256, but SHA-1 remains adequate for version control purposes with additional protections.

What should I use instead of SHA-1?

For general cryptographic hashing, use SHA-256 or SHA-3. For password hashing, use specialized algorithms like bcrypt, Argon2, or scrypt.

Need Secure Hashing?

Use our SHA-256 hash generator for modern, secure cryptographic hashing.