Cryptompress: A Symmetric Cryptography algorithm to deny Bruteforce Attack

Cryptompress, a new 128-bit (initial) private-key cryptography algorithm is proposed. It uses a block size of at least 30 bits and increments prior key size to additional 32 bits on each unsuccessful attempt of any means, including bruteforcing, further changing a specific portion of the cyphertext using the reformed Feistel network. Encryption process results from a proposed compression sequence developed using lookup table and shift operations followed by key generation. Eventually, four matrixes named add-sub matrix, reduced matrix, sequence matrix and term matrix are obtained which ultimately forms a cyphertext.

💡 Research Summary

The paper introduces Cryptompress, a novel symmetric‑key encryption scheme that aims to make brute‑force attacks impractical by dynamically expanding the secret key and by employing a multi‑stage compression‑based transformation before the final ciphertext is produced. The algorithm starts with a 128‑bit private key and processes plaintext in blocks of at least 30 bits. During encryption a “compression sequence” is applied: each block is looked up in a pre‑computed table, shifted, and then subjected to a series of matrix operations. Four distinct matrices are generated – the add‑sub matrix, the reduced matrix, the sequence matrix, and the term matrix – and their combined contents constitute the final ciphertext.

A central novelty is the “key auto‑expansion” mechanism. Whenever an unsuccessful decryption attempt is detected – for example, repeated authentication failures, abnormal error patterns, or any indication of a brute‑force trial – the algorithm automatically extends the key by an additional 32 bits. The newly generated bits are concatenated with the existing key and used in subsequent rounds. Information about the current key length is embedded covertly in the ciphertext, allowing the legitimate receiver to reconstruct the exact key state before decryption. Consequently, the effective key space grows geometrically with each failed attack, making exhaustive search exponentially more costly.

The encryption core is a re‑engineered Feistel network. Unlike classic Feistel designs that use a fixed round function and a predetermined number of rounds, Cryptompress selects the round function dynamically based on the current key length and the state of the four matrices. The number of rounds itself can increase or decrease as the key expands, ensuring that the internal structure of the cipher changes continuously. This variability thwarts attacks that rely on a static round structure, such as differential cryptanalysis that assumes a fixed set of S‑boxes or permutation patterns.

Security analysis in the paper argues that the combination of dynamic key growth and non‑linear matrix transformations provides resistance against linear and differential attacks, as well as side‑channel techniques that exploit predictable round functions. The authors claim that each failed brute‑force attempt adds 2^32 bits of entropy to the key, rapidly inflating the search space beyond feasible limits. They also discuss how the matrix operations introduce high algebraic degree and diffusion, making statistical attacks difficult.

However, the manuscript lacks several critical evaluations. First, there is no quantitative performance benchmark; the computational overhead of repeatedly expanding the key, updating matrix states, and transmitting key‑length metadata is not measured. Second, the synchronization protocol for key expansion between sender and receiver is described only at a high level, leaving open questions about robustness in noisy channels or when packet loss occurs. Third, the “key‑growth on failure” concept could be abused by an adversary to trigger a denial‑of‑service scenario, deliberately causing repeated failures to force the system to allocate ever‑larger keys and consume memory or processing resources. The paper does not propose mitigation strategies for such an attack vector.

In addition, the security proofs are largely heuristic. Formal proofs of indistinguishability under chosen‑plaintext or chosen‑ciphertext attacks are absent, and the resistance to modern algebraic attacks (e.g., Gröbner‑basis methods) is not examined. The authors also do not compare Cryptompress against established standards such as AES‑256 in terms of both security margin and efficiency, making it difficult to assess its practical advantage.

In summary, Cryptompress presents an inventive approach that blends dynamic key expansion with a compression‑driven, matrix‑heavy transformation and a flexible Feistel network. The idea of increasing key length after each failed attempt is conceptually appealing for thwarting brute‑force attacks, and the multi‑matrix design adds non‑linearity that could improve diffusion. Nonetheless, the scheme requires extensive empirical validation, rigorous security proofs, and a thorough analysis of potential denial‑of‑service exploitation before it can be considered a viable alternative to existing symmetric ciphers.