Sarun Rattanasiri midnight-wonderer

Consistent Overhead Byte Stuffing (COBS) is a clever way to prepare data for transmission so that a specific byte (usually 0x00) never appears in the message body, allowing it to be used reliably as a "end of packet" marker. Unlike traditional "escape-character" stuffing, which can double the size of your data in the worst case, COBS has a guaranteed maximum overhead of only 1 byte for every 254 bytes of data.

How COBS Encoding Works

COBS breaks your data into "code blocks." Each block starts with a code byte that tells the receiver how many bytes to skip to reach the next code byte.

Step-by-Step Process

Append a "Phantom" Zero: Conceptually, treat the end of your data as if there is a zero byte there.
Scan for Zeroes: Look at the first 254 bytes of your data.

I get an SSL error when AWS Lambda invokes dependencies that use a Let's Encrypt certificate.

Short description

Some AWS Lambda .NET Core and Ruby runtimes are experiencing certificate errors due to an expired Let's Encrypt cross-signed DST Root CA X3. For compatibility purposes, Let's Encrypt certificates default to using a certificate chain that's cross-signed by the DST Root CA X3 certificate that expired on September 30, 2021. OpenSSL versions 1.0.2 and earlier return an error when one of the verification paths is invalid, which prevents the successful establishment of SSL/TLS connections.

The following resolution removes the expired CA from the CA bundle and forces the system to use the file provided by the layer instead of the file packaged with the base system. OpenSSL versions 1.0.2 and earlier are forced to validate Let's Encrypt certificates using the alternate path provided in the environment variables.

Important: The system's trust store is frequently updated to include new CA root cer

BLAKE3 vs BLAKE2 benchmark for short input

Observed result

blake3 : 335251.50 per second
blake2s: 715722.22 per second
blake2b: 663446.58 per second

Conclusion from the result

Firmware in place
udev rules


	import { default as curry } from 'ramda/src/curry';

	function deleteChar(deleteCount: number, word: string): string[] {
	if (!(0 < deleteCount)) {
	return [word];
	}
	const accumulatedWordList = [];
	for (let wordIterator = 0; wordIterator < word.length; wordIterator++) {
	const deletedWord = `${

	# frozen_string_literal: true

	require 'securerandom'

	class RandomCode
	class NotSupported < ::StandardError
	end

	class P_Single < ::StandardError
	end

	path:
	/etc/apt/preferences.d

	command:
	apt policy
	apt-cache policy package-name

	content:
	Package: *
	Pin: release o=RepoNameFromPolicyCommand

	# start session
	ssh-agent $SHELL

	ssh-add ./destination-key
	ssh -i ./intermediate-key -A -t user@intermediate.example.com ssh -A user@destination.example.com

	# Cmnd alias specification
	Cmnd_Alias FIREWALL = /usr/sbin/ufw

	# User privilege specification
	username ALL=NOPASSWD: FIREWALL