Hi! I'm David,and I'm creating creating better web experiences.
Hello, my name is David Costa. I'm a Senior Software Engineer living in Brazil, creating solutions to help support our customers.
I work with Javascript and Typescript, using React as the main framework most of the time.
This website is intended to concentrate my articles, projects, and be a hub for my networks.
Latest posts
Which SSH agent signs for you: laptop, desktop and VPS
Why the key is in the agent and ssh still says no: inherited SSH_AUTH_SOCK, agent forwarding, tmux, ssh-askpass and IdentityAgent, with a laptop, a desktop and a VPS.
linuxsecuritysshOctober 16, 2026
SSH keys from the inside: how they work, the types and the risks
What happens when you connect with an SSH key, the difference between Ed25519, RSA and ECDSA, what the passphrase and the agent do, and the most common security problems, with real outputs.
linuxsecuritysshOctober 15, 2026
Keeping your SSH keys safe on Linux, macOS and Windows
Practical recommendations for keeping SSH keys: passphrases, an agent with a time limit, per-server config, hardware keys, the macOS Keychain, the Windows ssh-agent and what to do when a key leaks.
linuxsecuritysshOctober 15, 2026