SHA-1 Online Hash Generator
Generate secure SHA-1 hashes instantly using our free, browser-based tool. Enter any text or string and receive the 40-character hexadecimal SHA-1 hash with no installation, no signup, and no data sent to any server.
What is SHA-1?
SHA-1 (Secure Hash Algorithm 1) is a cryptographic hash function developed by the NSA and published by NIST in 1995. It produces a 160-bit (40 hexadecimal character) hash value from any input. SHA-1 was widely used in SSL certificates, digital signatures, and version control systems like Git.
In 2017, Google's Project Zero demonstrated the first practical SHA-1 collision attack (SHAttered), proving that two different files could produce the same SHA-1 hash. As a result, SHA-1 is now deprecated for security applications. For new projects, SHA-256 or SHA-3-256 are the recommended alternatives.
Is SHA-1 Still Used?
Yes — for non-security use cases, SHA-1 remains common:
- Git: Uses SHA-1 internally for object IDs (transitioning to SHA-256)
- File checksums: Verifying download integrity where collision attacks aren't a threat
- Legacy systems: Older APIs and protocols that haven't yet migrated
- Cache keys: Non-security fingerprinting of content
SHA-1 vs SHA-256
- Output length: SHA-1 = 160 bits (40 hex chars); SHA-256 = 256 bits (64 hex chars)
- Security: SHA-1 has known collisions; SHA-256 has no known practical attacks
- Speed: SHA-1 is slightly faster, but the difference is negligible for most use cases
- Recommendation: Use SHA-256 for anything security-sensitive
How to Use This Tool
- Enter the text you want to hash in the input box above.
- The 40-character SHA-1 hash is generated instantly as you type.
- Choose your output format: Hex, Base64, or Bytes.
- Click copy to use the result.
Features
- 100% browser-based — no data sent to servers
- Instant SHA-1 hash generation as you type
- Supports text input with UTF-8 encoding
- One-click copy of hash result
- Mobile and desktop friendly
Frequently Asked Questions
What is SHA-1?
SHA-1 (Secure Hash Algorithm 1) is a cryptographic hash function developed by the NSA and published by NIST in 1995. It produces a 160-bit (40 hexadecimal character) hash value. While once widely used, SHA-1 is now considered cryptographically weak due to demonstrated collision attacks.
Is SHA-1 still secure?
No, SHA-1 is not considered secure for cryptographic purposes. In 2017, Google's Project Zero demonstrated the first practical SHA-1 collision (SHAttered attack). Major browsers and CAs have deprecated SHA-1 certificates. For any security application, use SHA-256 or SHA-3.
When can I still use SHA-1?
SHA-1 is acceptable for non-security uses such as file checksums, cache keys, content-addressable storage (like Git uses internally), and legacy system compatibility where collision resistance is not a security requirement.
What is the SHA-1 output length?
SHA-1 always produces a 160-bit hash, displayed as 40 hexadecimal characters. This is shorter than SHA-256 (64 hex chars) and SHA-512 (128 hex chars).
SHA-1 vs SHA-256: what is the difference?
SHA-1 produces a 160-bit hash and has known collision vulnerabilities. SHA-256 produces a 256-bit hash with no known practical attacks. For any new project or security-sensitive code, SHA-256 is the correct choice.
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