SHA-1 Hash Generator
Generate SHA-1 (160-bit) hashes from text or files. Supports HMAC-SHA1 and file checksum verification.
SHA-1 Hash
40 hex characters (160 bits)Enter text and click Generate to create a SHA-1 hash
File SHA-1 Hash
Drop a file here or click to select
Max 50 MB
Select or drag a file above to compute its SHA-1 checksum. Processing happens entirely in your browser when possible.
Other Hash Algorithms
What is SHA-1?
SHA-1 (Secure Hash Algorithm 1) is a cryptographic hash function that produces a 160-bit (20-byte) hash value, displayed as a 40-character hexadecimal string. Published by NIST in 1995 as part of the Digital Signature Algorithm, SHA-1 was the standard for digital signatures and certificates for over 15 years.
How SHA-1 Works
SHA-1 processes input in 512-bit blocks through 80 rounds of operations. It maintains a 160-bit state (five 32-bit words) and uses message expansion, bitwise operations, and modular addition. Each round applies a different logical function (Ch, Parity, Maj) and a round constant.
Output
40 hex characters (160 bits)
Year
1995
Status
⚠ Deprecated
Common Use Cases
- Git version control (commit identifiers)
- Legacy certificate verification
- HMAC-SHA1 for OAuth 1.0 and TOTP
- Non-security file checksums
- Data deduplication
Security Considerations
SHA-1 is deprecated for security use. Google demonstrated a practical collision attack (SHAttered) in 2017, producing two different PDFs with the same SHA-1 hash. All major browsers and CAs stopped accepting SHA-1 certificates. Use SHA-256 or SHA-3 for security applications.
SHA-1 vs Other Algorithms
SHA-1 provides 160 bits of output, falling between MD5 (128 bits) and SHA-256 (256 bits). While stronger than MD5, the 2017 SHAttered attack proved SHA-1 collisions are practical. SHA-256 remains unbroken and is the recommended replacement. Git is gradually migrating from SHA-1 to SHA-256.