sha1($salt.$pass.$salt) Hash

What is sha1($salt.$pass.$salt)?

The cryptographic hash format `sha1($salt.$pass.$salt)` is a variant of the SHA-1 algorithm adapted for password storage, where the input is constructed by concatenating a salt (`$salt`), the raw password (`$pass`), and the salt again (`$salt`). This structure originates from early password hashing schemes designed to mitigate rainbow table attacks by introducing uniqueness via per-user salts. SHA-1 itself was standardized in 1995 as part of the Secure Hash Algorithm family, originally intended for digital signatures and data integrity verification, but later repurposed for password hashing due to its deterministic, fixed-length output (160-bit hash). The primary use-case of this format was to store user credentials securely by combining the password with a random salt before hashing, ensuring that even identical passwords produced different hashes across users. However, its adoption in password storage was later criticized due to known cryptographic weaknesses, leading to its deprecation in favor of stronger algorithms like SHA-256 or bcrypt.

This format is vulnerable to cracking primarily due to SHA-1’s inherent cryptographic flaws and the inefficiency of its salt implementation. SHA-1 is susceptible to collision attacks—where two distinct inputs produce the same hash—due to its 160-bit output space, which is now considered too small for modern computational power. Additionally, the concatenation of salt-pass-salt (`$salt.$pass.$salt`) does not inherently increase security beyond a single salt application; it merely doubles the salt’s length without altering the fundamental collision resistance. More critically, SHA-1 lacks built-in resistance to brute-force or GPU-optimized attacks (e.g., via CUDA or OpenCL), as its fixed-length output enables parallelized cracking via techniques like GPU-based rainbow tables or precomputed hash lookups. The absence of a slowdown function (unlike bcrypt or Argon2) allows attackers to evaluate millions of hashes per second, rendering the scheme impractical for modern security standards.

Identifying sha1($salt.$pass.$salt) Hashes

Identifying a hash blindly is often difficult because multiple algorithms can output strings of the exact same length. For example, a standard 32-character hexadecimal string could be MD5, NTLM, MD4, or LM. To definitively identify sha1($salt.$pass.$salt), security researchers analyze the hash against a strict regular expression (regex) signature (shown above) to find structural matches.

How to Crack sha1($salt.$pass.$salt)

If you need to recover the plaintext password for a sha1($salt.$pass.$salt) hash during a penetration test or forensics investigation, you must supply the correct module ID to your cracking software. Use the exact commands provided at the top of this page to target the hash successfully.