Deeptiman

Yes I agree, ROM, CD, and DVD are read-only drives. But the manufacturer writes the data. My perspective comes from hardware design, where even for read-only drives, the data-writing decision is made during manufacturing.

Example: When using a precomputed lookup table for the AES S-Box, ROMs are designed to create memory banks for faster arithmetic operations. During the design phase, you must make careful trade-offs regarding how much space to allocate for storing precomputed values. From the start, you need to floorplan how to write these precomputed arrays to achieve realistic space allocation. For this reason, algorithms like Canright's Boolean network are more suitable for compact design and are more efficient at reducing physical memory area.

It was my mistake to write it as general-purpose, and my wording was confusing. Thank you for highlighting this. I will read the article again and improve the writing.

You are right, I wrote in an oversight that "Zero access latency" is practically possible within some margin. I was reading the book "The Cache Memory by Jim Handy" and on section 2.1.3 which says:

"Occasionally, a designer will allow the CPU address to propagate through the address buffers to the bus at the beginning of every cycle, whether the cycle turns out to be a read hit or a read miss. The cache is designed in such a way as to initiate a main memory access at the same time as the cache access, rather than to wait for a cache miss before commencing the main memory access. This approach can shorten the main memory access time in the event of a cache miss and will serve to improve the operation of singleprocessor, single-tasking systems, but can work to the detriment of multitasking systems and multiprocessing systems, since the cache will allow the CPU to waste considerable amounts of main memory bus bandwidth. Such caches can be referred to as look aside designs. Since the processor has the option of going to either the cache or main memory at all times to request data, the look aside cache can be an add-on to the computer system."

Because the book mainly focused on the older i386 processor memory design, I could have been clearer when describing common characteristics. I updated the common characteristics to include "Higher data-rate processing," which is relevant to the Prefetch architecture and its intent to support more data bits.

Cryptographic hash functions are foundational to the construction of practical cryptographic systems. A hash function transforms input data of arbitrary length into a fixed-length message digest that is easy to compute but impossible to invert. Once a digest is produced, recovering the original message is computationally infeasible. Hash functions are widely used in cryptographic applications, including verifying data integrity, authenticating messages, generating deterministic randomness, and deriving keys for secure communication protocols.

This article provides a detailed design of the FIPS 202 standard. I'll begin by explaining the sponge construction and its security properties, then examine how SHA-3 achieves diffusion and irreversibility through its internal permutation. Along the way, I'll clarify which components of the design are reversible in isolation and why the overall construction remains a one-way function. Finally, the SHA-3 and SHAKE design will highlight that they are particularly well-suited for modern cryptographic systems, including post-quantum cryptography.

A structured visualization of the Elliptic Curve Method (ECM), relating j-invariant classes and curve selection to Palm Jumeirah’s frond layout.

Imagine the Elliptic Curve Method as exploring Palm Jumeirah, Dubai’s iconic palm-shaped island. The island represents an elliptic curve y² = x³ + ax + b mod M, where M is the number to factor (a product of unknown primes). Fronds are j-invariants classifying curve shapes, points (x, y) are coordinates to probe, and the group order (number of points modulo a hidden prime p) is like the frond’s “explorable paths” bounded by Hasse’s theorem: |#E(Fₚ) — (p+1)| ≤ 2√p.

Imagine the Elliptic Curve Method as exploring Palm Jumeirah, Dubai’s iconic palm-shaped island. The island is the elliptic curve (y² = x³ + ax + b (mod M)), a structured algebraic space defined over a composite modulus M. Each frond of the island corresponds to a j-invariant, classifying the curve’s isomorphism class and defining a unique section of the island. Points on the curve (x, y) are like coordinates along a frond, while the group order corresponds to the frond’s area.