alexwebr

hi DiffAdd      ctermfg=7 ctermbg=4
hi DiffChange   ctermfg=7 ctermbg=4
hi DiffDelete   ctermfg=7 ctermbg=4
hi DiffText     ctermfg=7 ctermbg=1

alexwebr

#include <string.h>
#include <stdio.h>
#include <assert.h>

// Find this with:
// git grep 'strncpy(\([^,]\+\), [^,]\+, sizeof(\1));'

int main(int argc, char *argv[])
{
        // Take a single string argument

alexwebr

# Iterates through its elements, starting at the beginning, forever.
class CircularList
  def initialize values
    @values = values
    @index = 0
  end

  def next
    value = @values[@index]
    @index += 1

alexwebr

#include <stdio.h>

const char *path = "/sys/devices/LNXSYSTM:00/LNXSYBUS:00/TOS6208:00/backlight/toshiba/brightness";

int main(int argc, char *argv[])
{
        if (argc != 2) {
                fputs("Need exactly one argument", stderr);
                return 1;
        }

alexwebr

What's this all about?

Digital cryptography! This is a subject I've been interested in since taking a class with Prof. Fred Schneider back in college. Articles pop up on Hacker News fairly often that pique my interest and this technique is the result of one of them.

Specifically, this is about Lamport signatures. There are many signature algorithms (ECDSA and RSA are the most commonly used) but Lamport signatures are unique because they are formed using a hash function. Many cryptographers believe that this makes them resistant to attacks made possible by quantum computers.

How does a Lamport Signature work?

alexwebr

// [... snip ...]

void free_tree(tree_t *p) 
{
  if (p->sibling != NULL) {
    free_tree(p->sibling);
    p->sibling = NULL;
  }

  if (p->child != NULL) {