Chaos-based image ciphers may exhibit favorable statistical metrics while retaining a recoverable algebraic structure. We analyze the modified one-time-pad image cryptosystem of Stoycheva et al., which combines static, Chua-system-derived, and neural masks with channel-wise shuffling and XOR. For observations sharing a fixed or reproduced induced state, we prove that each color channel is equivalent to a plaintext-independent permutation followed by an XOR keystream. The trained neural component supplies a mask but does not alter this external structure. Established base-256 position labels recover the complete equivalent mapping with four chosen-plaintext queries for a 512-by-512 image; known-plaintext, chosen-ciphertext, differential, and black-box analyses are evaluated under explicitly stated access conditions. Under the same state, a one-byte plaintext difference changes exactly one ciphertext byte. We also specify a redesign that renews the three key components per image and couples cross-channel routing and masking to preceding ciphertext bytes. Its inverse is proved correct. Across 15 image–function trials, decryption was byte exact. Advancing the image counter changed 99.603907% of ciphertext bytes for the same image, and none of eight tested input pairs satisfied the fixed permutation–XOR affine identity. These results identify the state condition required by the recovery procedures and characterize the tested behavior of the redesigned image transformation.

Researchers at Guangdong University of Technology have broken a chaos-based image cryptosystem whose dynamic key was designed to resist attack, using an equivalent-structure transformation and a

In early 1978, Robert McEliece at Caltech’s Jet Propulsion Laboratory in Pasadena published a technical report on a public-key cryptosystem built on error-correcting codes. The mathematics was sound. The keys were the size of a short novel. That same month, RSA’s creators submitted a paper with…

A user is experiencing difficulties with the TryHackMe Cryptosystem challenge while attempting to run a Python script designed to crack RSA ciphertext. They are running the script on bare metal Ubuntu and receiving an error message. The user suspects there may be an issue with the cryptodome library and is requesting assistance.

The McEliece cryptosystem based on algebraic geometry codes has been proposed as a way to reduce the key size of code-based cryptography, but several structural attacks have demonstrated the vulnerability of particular families of algebraic geometry codes. Despite this, until recently, there remained schemes and parameter sets that were not vulnerable to any known attack. We propose a new structural attack with ``hints'' that applies to elliptic codes with arbitrary effective divisors. In particular, we prove that, given the elliptic curve, the public generator matrix, and three points from the evaluation divisor, the entire divisor can be recovered in polynomial time, independently of the number of errors used in the cryptosystem. The attack requires $\mathcal{O}(k^2n^2+|\mathcal{E}(\mathbb{F}_q)|+n)$ operations in $\mathbb{F}_q$ and succeeds with overwhelming probability, after which the second divisor is recovered in $\mathcal{O}\!\left(k^2n^2 + (|\mathcal{E}(\mathbb{F}_q)|-n)n^2\right)$ operations. We further propose an optimized version of the attack that requires no additional information at all. Exploiting the action of the automorphisms of the curve, the three known points are replaced by the enumeration of a single pair of field elements, which yields an equivalent key on the given public curve in $\mathcal{O}\!\left(k^2n^2 + q^2 + (|\mathcal{E}(\mathbb{F}_q)|-n)n^2\right)$ operations on average.

The McEliece code-based cryptosystem, utilizing binary Goppa codes, is the earliest public-key encryption scheme that is still considered post-quantum secure. We present a simple, classical quasipolyn...