lifthrasiir

What the heck?

• Schemaless: The format does not have a knowledge about the underlying data at all.
• Byte-oriented: The format is built upon a byte stream, probably for the ease of implementation and performance.
• Binary: The format is not targeted for human consumption and specified in terms of "bytes" (which is 8 bits long for our purpose).
• Serialization: The format is primarily to be used for storage and transmission, not for the in-memory representation.

Contenders

• S-Expressions (1997), a "canonical" encoding (which is also used for transport)

lifthrasiir

This proposal was originally written in 2018 as a concrete proposal for numeric time zone identifiers. I'm still not sure if this has a merit or not, but for the historical perspective, I reproduce the (incomplete) proposal in verbatim here. --Kang Seonghoon

---

[...]

The needs for the short and stable identifier are most importantly observed by the case of the Unicode CLDR project. CLDR required a stable identifier for the locales, which requires a stable identifier for the time zones. [...]

Short Identifiers

lifthrasiir

/* The world's smallest Brainfuck interpreter in C, by Kang Seonghoon
 * http://j.mearie.org/post/1181041789/brainfuck-interpreter-in-2-lines-of-c */
s[99],*r=s,*d,c;main(a,b){char*v=1[d=b];for(;c=*v++%93;)for(b=c&2,b=c%7?a&&(c&17
?c&1?(*r+=b-1):(r+=b-1):syscall(4-!b,b,r,1),0):v;b&&c|a**r;v=d)main(!c,&a);d=v;}

lifthrasiir

// Brotli bootstrapping based on WOFF2 font
// Kang Seonghoon, 2024-03-01, public domain
// Based on my earlier work for JS1024: https://js1024.fun/demos/2022/18
// Only vaguely tested, YMMV

import { argv, stderr } from 'node:process';
import fs from 'node:fs';
import zlib from 'node:zlib';

const generateBrotliParams = function* ()  {

lifthrasiir

The "Options" Alphabet

https://www.youtube.com/watch?v=knXGYSdtr_k

Transcripts

p1: "The information search for <two unrecognizable words>"

dDv- Nv-
Xo S Go D-

lifthrasiir

# derived from https://github.com/crozone/ReedSolomonCCSDS
# should be more performant alternative to https://github.com/kplabs-pl/reed-solomon-ccsds

from dataclasses import dataclass
from typing import Optional, List

ALPHA_TO = [
    0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80,0x87,0x89,0x95,0xad,0xdd,0x3d,0x7a,0xf4,
    0x6f,0xde,0x3b,0x76,0xec,0x5f,0xbe,0xfb,0x71,0xe2,0x43,0x86,0x8b,0x91,0xa5,0xcd,
    0x1d,0x3a,0x74,0xe8,0x57,0xae,0xdb,0x31,0x62,0xc4,0x0f,0x1e,0x3c,0x78,0xf0,0x67,

lifthrasiir

고수준에서 암호학 이해하기

이 글은 메아리 저널에 쓸 목적으로 한동안 작업하던 글입니다. 메아리 특유의 디자인(...)이 싫다면 여기로 링크하셔도 됩니다. 어느 쪽이든간에 의견은 이 아래의 코멘트 란 또는 메아리에 기재되어 있는 메일 주소를 써 주시면 감사하겠습니다. --lifthrasiir

암호학을 사용하는 많은 시스템은 세부적으로 무슨 알고리즘을 쓰는지보다는 그 알고리즘들이 어떻게 연결되어 있는지, 즉 구조가 실제 안전성에 더 큰 영향을 미친다. 따라서 구조와 그 구조를 이루는 빌딩 블럭을 아는 것이 중요한데, 여기에서는 이러한 암호학적 빌딩 블럭과 함께 블럭들이 어떻게 쓰여서 더 큰 구조를 만드는지를 알아 본다.

Key Exchange

키 교환. 두 사람만이 알 수 있는 새로운 키를 만든다. 이 과정이 끝나도 상대방이 내가 아는 사람인진 알 수 없지만 적어도 상대방과 내가 같은 키를 가지고 있다는 건 확신할 수 있다.

lifthrasiir

• 마지막 갱신: 2020-08-17T15:40+09:00
• 영상: https://www.youtube.com/watch?v=_hjRvZYkAgA
• 레퍼런스
  • McMullen, P., Schulte, E. Regular Polytopes in Ordinary Space. Discrete Comput Geom 17, 449–478 (1997). https://doi.org/10.1007/PL00009304
  • Dress, A. W. M. (1985). A combinatorial theory of Grünbaum’s new regular polyhedra, Part II: Complete enumeration. Aequationes Mathematicae, 29(1), 222–243. https://doi.org/10.1007/bf02189831

일반적인 용어가 없거나 부적절하여 새로 만들어낸 용어는 *로 표시함.
일부는 영어로도 정립된 용어가 없는데 이 경우 영어에도 *가 붙어 있음.

기본 용어

lifthrasiir

# This script builds a custom Zig distribution into a Python wheel.
#
# The "custom" distribution refers to any directory resulting from
# zig-bootstrap that doesn't make into public nightly or stable releases.
# The existing ziglang/zig-pypi doesn't work with such cases, hence
# this script. It still makes use of a large portion of make_wheels.py,
# so should be put into the same directory in order to function.
#
# This script is derived from make_wheels.py from zig-pypi (commit
# 5b30070bc), and thus distributed under the same license (MIT/Expat).

lifthrasiir

struct tape { mem: ~[u8], ptr: uint }
pure fn tape() -> tape { tape { mem: vec::from_elem(10000u, 0u8), ptr: 0 } }

macro_rules! bf_rec(
    () => ();

    (+) => (tape.mem[tape.ptr] += 1u8);
    (-) => (tape.mem[tape.ptr] -= 1u8);
    (>) => (tape.ptr += 1u);
    (<) => (tape.ptr -= 1u);