Generador de Hash SHA-1

The Secure Hash Algorithm 1 (SHA-1) is a cornerstone of modern digital history. Defined in FIPS PUB 180-4, it is designed to take an input of any length and produce a fixed-size, 160-bit (20-byte) message digest. While SHA-1 is now deprecated for high-security applications, it remains a vital utility for Git Version Control and legacy system verification.

The SHA-1 engine processes data through a sequence of bitwise rotations and logical shifts:

1. Block Padding: The input is padded with a 1 bit followed by zeros until it is 64 bits short of a multiple of 512. The original length is then appended.
2. State Initialization: Five 32-bit internal variables (h0 through h4) are initialized with constants derived from the square roots of the first five prime numbers.
3. Message Schedule Creation: Every 512-bit block is expanded into a series of eighty 32-bit words using a recursive XOR and rotation pattern.
4. The 80 Rounds: The core engine executes 80 rounds of processing. Each round uses different auxiliary functions (Ch, Parity, Maj) and a set of constant "K" values.
5. Iterative Compression: In each round, the internal variables are shuffled and mixed with the message words, ensuring that every bit of the input influences every bit of the output.
6. Final Digest: The four variables are concatenated to create the final 40-character hexadecimal string.

The History of SHA-1 and the NSA

SHA-1 was developed by the National Security Agency (NSA) and published by NIST in 1995. It was a corrected version of the original "SHA" (now called SHA-0), which contained a secret flaw.

For over two decades, SHA-1 was the global standard for SSL/TLS certificates and secure electronic signatures. However, in 2017, the SHAttered attack—a collaboration between Google and CWI Amsterdam—proved that SHA-1 could be broken using massive computing power. Today, SHA-1 is strictly recommended only for data integrity and Software Checksums.

Technical Comparison: SHA-1 vs. SHA-256 vs. BLAKE3

Understanding the trade-offs in security and compute cost is key for modern developers.

Feature	SHA-1 (FIPS 180)	SHA-256 (FIPS 202)	BLAKE3 (Modern)
Bit Length	160-bit	256-bit	256-bit
Hash Rounds	80	64	7
Collision Proof?	No (SHAttered)	Yes (Current)	Yes (Current)
Git Usage	Standard	Experimental Opt-in	None
Creator	NSA	NSA	O'Connor / Aumasson

By using a dedicated SHA-1 Generator, you can accurately verify the integrity of your Open Source Software or audit legacy Commit Hashes in your repositories.

Security Considerations: The SHAttered Attack

The "death" of SHA-1 was a major milestone in world cryptography:

• Collision Reality: In 2017, researchers proved they could create two different PDF files with the exact same SHA-1 hash. This means SHA-1 can no longer be trusted for digital contracts or identity verification.
• Git and SHA-1: Interestingly, Git still uses SHA-1 for its object model. However, it includes "Hardened" SHA-1 checks to prevent the SHAttered attack from corrupting repositories.
• Certificate Revocation: Major browsers began flagging SHA-1 certificates as insecure in 2017. You should always use SHA-256 for any modern website security.
• Client-Side Privacy: To maintain the highest Data Privacy standards, all hashing is performed locally in your browser. Your private keys, code snippets, and logs are never sent to a server.