We study error-detection and error-correction codes for computationally bounded adversarial channels. We consider seeded codes where the polynomial-time encoding and decoding procedures share a public random seed, but are otherwise deterministic. An adversarial channel gets this seed and can perform arbitrary polynomial-time computation to adaptively select both the message to be encoded and a bounded number of errors to be added to the resulting codeword. The goal is to detect or correct such errors with overwhelming probability, while achieving better trade-offs between rate and error tolerance than those possible for computationally unbounded channels. For large alphabets, prior work (ITCS ‘25) achieves essentially optimal parameters under minimal cryptographic assumptions. However, for the binary alphabet, prior works (TCC ‘20, EUROCRYPT ‘25) either only achieved a weaker notion of selective security under the learning with errors (LWE) assumption, or relied on non-standard cryptographic assumptions to get the full notion of adaptive security. In this work, we construct binary codes that achieve the full notion of adaptive security assuming trapdoor hashing, which can in turn be instantiated under a variety of standard cryptographic assumptions such as LWE, or Decisional DiffieHellman (DDH), or Quadratic Residuosity (QR), or Decisional Composite Residuosity (DCR). For error detection, our codes get essentially optimal rate $R \approx 1$ and relative error tolerance $p \approx \frac{1}{2}$. For error correction, they can uniquely correct $p\lt1 / 4$ fraction of errors with a rate R matching that of the best known list-decodable codes for this error tolerance. As a central technical tool of potentially independent interest, we construct multi-input correlation intractable hashing for “shifted output relations” under the standard cryptographic assumptions above.

Suppose a user wants to broadcast an encrypted message to K recipients. With public-key encryption, the sender would construct K different ciphertexts, one for each recipient. The size of the broadcasted message then scales linearly with K. A natural question is whether the sender can encrypt the message with a ciphertext whose size scales \em sublinearly with the number of recipients.

OTDOA (Observed Time Difference of Arrival) is a positioning method available in LTE. User Equipment (UE) that supports OTDOA requires assistance data from a location server. The quality of the assistance data directly impacts the UE measurement accuracy. The assistance data are specifications of a reference and neighbor cells for UE to measure. Expected RSTD (Reference Signal Time Difference) is included with the neighbor cell information. An analytic solution for computing the Expected RSTD and Expected RSTD uncertainty is proposed. The analytic solution is applied during generation of assistance to avoid possible PCI (Physical Cell Identity) ambiguity in OTDOA positioning. The overall goal with this analytic solution is to increase the final OTDOA positioning accuracy.