CRC-96(ZIP) Hash

What is CRC-96(ZIP)?

The **CRC-96(ZIP)** hash format is a variant of the **Cyclic Redundancy Check (CRC)** polynomial-based error-detection mechanism, originally standardized in the **ZIP file format (PKZIP, RFC 1951)** as a lightweight integrity check for compressed data. Derived from the **CRC-32** family, CRC-96(ZIP) employs a **96-bit (12-byte) polynomial divisor** (specifically, `0x04C11DB7` for the initial seed, though later revisions in ZIP 64 and other implementations may vary) to generate a checksum via bitwise XOR operations over the input data. Unlike cryptographic hashes, CRC-96(ZIP) was not designed for security but for **error detection in storage and transmission**, leveraging its **deterministic, fast computation** and **minimal memory footprint**. The algorithm processes data in **little-endian byte order**, with a **predefined initial seed (e.g., 0x00000000 for CRC-32, but extended to 96 bits in ZIP)** and a **final XOR mask** (e.g., `0xFFFFFFFF` for CRC-32, expanded to `0xFFFFFFFFFFFFFFFF` for CRC-96) to produce the final checksum. Its primary use-case remains **data integrity verification** in archived files, though it is occasionally misused in security contexts due to its perceived "hash-like" output.

CRC-96(ZIP) is fundamentally vulnerable to **collision attacks and brute-force cracking** due to its **non-cryptographic design principles**. The algorithm lacks **salting**, **iterative hashing**, or **avalanche effects**, making it susceptible to **preimage and second-preimage attacks** with relatively modest computational effort. Modern **GPU/ASIC acceleration** (e.g., via FPGA or SIMD-optimized implementations) can evaluate trillions of CRC-96(ZIP) values per second, enabling **birthday-bound collision attacks** in impractical but feasible timeframes for short inputs. Additionally, the **deterministic nature** of CRC (no entropy sources or keyed operations) allows adversaries to exploit **known-plaintext attacks** or **rainbow table precomputations** for targeted forgeries. Unlike cryptographic hashes (e.g., SHA-3), CRC-96(ZIP) lacks **mathematical proof of resistance** to quantum or classical attacks, and its **linear feedback structure** enables **differential cryptanalysis** to craft inputs with predictable checksums. While not suitable for authentication or digital signatures, its **speed and simplicity** make it a prime target for **hash collision exploits** in legacy systems.

Identifying CRC-96(ZIP) 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 CRC-96(ZIP), security researchers analyze the hash against a strict regular expression (regex) signature (shown above) to find structural matches.

How to Crack CRC-96(ZIP)

If you need to recover the plaintext password for a CRC-96(ZIP) 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.