cky

#!/usr/bin/ruby
require 'openssl'

TYPES = {
  6 => {magic: 'RSA1', private_key: false},
  7 => {magic: 'RSA2', private_key: true}
}

data = ARGV[0] ? File.binread(ARGV[0]) : $stdin.binmode.read
type, version, algo, magic, bits, rest = data.unpack('ccx2l<a4l<a*')

cky

(use-srfis '(1 69))
(read-hash-extend #\#
  (lambda (c port)
    (define ht (make-hash-table eqv?))
    (define (ht-ref key)
      (hash-table-ref ht key (lambda ()
                               (define sym (gensym))
                               (hash-table-set! ht key sym)
                               sym)))
    (define (hash-key x)

cky

Find the shortest way to write CipherSaber. There are several parts to this puzzle:

RC4/Arcfour

Arcfour is fully specified elsewhere, but for completeness, I'll describe it here.

Key setup

Set up two arrays, S and S2, both of length 256, where k_1 is the first byte of the key, and k_n is the last.

cky

;;;; SHA-1 and SHA-2 implementations.
;;;; Uses R7RS bytevector and byte I/O interfaces.
;;;; Requires SRFIs 1, 26, 43, and 60.

;;; Auxiliary definitions to avoid having to use giant tables of constants.

(define primes80 '(2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73
                   79 83 89 97 101 103 107 109 113 127 131 137 139 149 151 157
                   163 167 173 179 181 191 193 197 199 211 223 227 229 233 239
                   241 251 257 263 269 271 277 281 283 293 307 311 313 317 331

cky

#100DaysOfCode Log—Round 1—Chris Jester-Young

The log of my #100DaysOfCode challenge. Started on 1 January 2018.

Log

R1D1 (2018-01-01)

Created [SwiftJson] as a Swift port of [ktjson] and [c++17-json]. Coded up the basic JsonValue enum type.

cky

function flatten(x) {
    var result = [];
    var appendToResult = function (xs) {
        result.splice(result.length, 0, ...xs);
    }
    if (Array.isArray(x)) {
        x.map(flatten).forEach(appendToResult);
    } else {
        result.push(x);
    }

cky

#lang racket
(define (expmod base exp m)
  (let recur ([exp exp])
    (cond [(zero? exp) 1]
          [(even? exp) (let* ([prev (recur (quotient exp 2))]
                              [result (modulo (sqr prev) m)])
                         (if (and (< 1 prev (sub1 m))
                                  (= result 1))
                             0
                             result))]

cky

#lang racket
(define (determinant p1 p2)
  (- (* (car p1) (cdr p2))
     (* (cdr p1) (car p2))))

(define points (read))
(define first (cons (read) (read)))
(define-values (area last)
  (for/fold ([area 0] [last first])
            ([i (in-range (sub1 points))]

cky

(define-syntax pollute-my-namespace
  (let ((letters "abcdefghijklmnopqrstuvwxyz_")
        (char->symbol (compose string->symbol string)))
    (define (make-macros stx)
      (lambda ()
        (for*/lists (ids syntaxes)
                    ((x letters)
                     (y letters))
          (if (char=? x y)
              (values (datum->syntax stx (char->symbol #\^ x))

cky

Code-golf? What's that?

Code-golf is a competition to solve a particular problem in the fewest bytes of source code.

What are the requirements of a code-golf?

• The question must be Community-wiki. Please flag for moderator attention to make it so.