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 This Page Processes Input
Text and files on this page are hashed in your browser with
SubtleCrypto using SHA-1; they are not uploaded by this tool.
The supported browser digest names are defined by the
W3C Web Cryptography specification.
SHA-1 and SHA-2 are specified in NIST FIPS 180-4; SHA-3 is specified in NIST FIPS 202. For workflows and limitations, see file hash verification, HMAC, and hashing versus encryption.
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.