sha1(sha1(sha1($pass))) Hash

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

The cryptographic hash format `sha1(sha1(sha1($pass)))` represents a triple-SHA-1 composition, where the input password is iteratively hashed three times using the SHA-1 algorithm. SHA-1 (Secure Hash Algorithm 1), designed by the NSA and standardized as FIPS 180-1 in 1995, is a 160-bit cryptographic hash function that processes input data into a fixed 20-byte (160-bit) hash value via a compression function incorporating bitwise operations, modular arithmetic, and a fixed 80-round message schedule. This triple-hashing construct emerged as a rudimentary defense against brute-force attacks by increasing computational overhead, though it was never formally standardized. Its primary use-case was in legacy systems—particularly early web applications and password storage schemes—where developers sought to mitigate plaintext exposure by obscuring passwords with multiple hash iterations. However, this approach was inherently flawed, as it relied on ad-hoc obfuscation rather than cryptographic best practices like salting or key stretching, making it vulnerable to systematic exploitation.

The vulnerability of `sha1(sha1(sha1($pass)))` stems from fundamental design flaws exacerbated by cryptographic advancements. SHA-1 itself is now considered broken due to its susceptibility to collision attacks (e.g., SHA-1 has been cracked in controlled environments with pre-image attacks requiring ~2^69 operations) and its inability to resist length-extension attacks. The triple-hashing iteration, though intended to slow attacks, provides no security benefit—SHA-1’s 160-bit output remains vulnerable to brute-force cracking via GPU/ASIC clusters (e.g., modern password crackers like Hashcat achieve SHA-1 hashes at rates exceeding 100+ GH/s). Worse, the absence of a cryptographic salt means identical passwords produce identical hashes, enabling offline rainbow table attacks. Additionally, the fixed iteration count lacks adaptive resistance; unlike modern schemes like PBKDF2 or bcrypt, it cannot dynamically adjust computational cost, rendering it obsolete against optimized hardware acceleration. The format’s demise is further cemented by NIST’s deprecation of SHA-1 for security purposes, as its collision resistance has been shattered (e.g., the 2017 SHA-1 collision attack by Chenevier and others).

Identifying sha1(sha1(sha1($pass))) 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(sha1(sha1($pass))), security researchers analyze the hash against a strict regular expression (regex) signature (shown above) to find structural matches.

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

If you need to recover the plaintext password for a sha1(sha1(sha1($pass))) 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.