SHA1 Hash Generator
Generate SHA1 checksums for text and massive files (10GB+). Features secure client-side streaming, hex/base64 output, and automated integrity comparison.
About
The Secure Hash Algorithm 1 (SHA-1) is a cryptographic hash function that produces a 160-bit (20-byte) hash value, typically rendered as a 40-digit hexadecimal number. While functionally deprecated for collision resistance in high-security digital signatures, it remains a critical standard for file integrity verification (checksums), Git version control objects, and legacy data identification.
Unlike standard web-based tools that crash on large files, this tool utilizes a Chunked Streaming Engine. It processes files of any size (ISOs, backups, raw video) locally within your browser by reading byte streams in small blocks, ensuring your data never leaves your device and your RAM is never overloaded.
Formulas
SHA-1 processes messages in 512-bit blocks. The core compression function mixes the current block M with the internal state H using bitwise operations.
The State Update Function:
For t from 0 to 79:
T = ROTL5(a) + ft(b, c, d) + e + Kt + Wt
Where ROTL is circular left shift, and K represents the four round constants derived from square roots of 2, 3, 5, and 10.
Reference Data
| Feature | SHA-1 | MD5 | SHA-256 |
|---|---|---|---|
| Output Size | 160 bits | 128 bits | 256 bits |
| Block Size | 512 bits | 512 bits | 512 bits |
| Rounds | 80 | 64 | 64 |
| Security Level | Low (Collision Found) | Compromised | High |
| Primary Use Case | Legacy Integrity, Git | Non-crypto Checksum | Modern Security |
| Performance (Relative) | 1.0x | 1.3x | 0.6x |
| RFC Standard | RFC 3174 | RFC 1321 | RFC 6234 |