This letter was originally published in our 2024 Annual Report.
The past year at ISRG has been a great one and I couldn’t be more proud of our staff, community, funders, and other partners that made it happen. Let’s Encrypt continues to thrive, serving more websites around the world than ever before with excellent security and stability. Our understanding of what it will take to make more privacy-preserving metrics more mainstream via our Divvi Up project is evolving in important ways.
Well it stands to reason, that TLS, i.e. Transport-Layer-Security, would secure the transport, and not secure the server providing the service against intrusion.
Also how is your hypothetical related to cost of certificates? If you use an expensive certificate with in person validation of your organization and its ownership of the domain name (these types of certs exist), then how does that change the case where your site is hacked, compared to the free certificate?
You can distribute your public key, and have people manually add it to their trust stores.
But OSs and browsers ship with preloaded trusted certificates. This way, the owner of a preloaded trusted certificate can issue new certificates that are automatically trusted by people’s OSs and browsers.
To become a preloaded trusted certificate owner, I imagine that there are stringent audits and security requirements. Part of that will be verifying the identity of the requester before issuing them a certificate.
With LetsEncrypt, they either need to talk to a server hosted at the domain to retrieve a token (generated when the request is initiated).
This proves the requester owns/controls the domain and the server (the requester has correctly set up DNS records, and placed the required token on the server). This is HTTP challenge mode.
The other method is by a DNS challenge. The requester adds a TXT record to their nameservers with the token value, letsencrypt then inspects the DNS records for the domain and will issue a cert when it sees the token. This proves the requester owns/controls the domain.
So, proving identity is required (otherwise anyone could generate a trusted cert for any domain). And trusted certificate issuers are required, so people don’t have to constantly import (possibly dodgy) public keys
And how does the client validate that your public key is actually your public key and not some attacker’s?
The idea of having a trusted 3rd party is to ensure that some impartial and trustworthy arbiter can confirm to the client that yes, this certificate is trustworthy, because they issued it to the correct party.
But you can absolutely self-sign a certificate. Works just fine, though not all clients accept self-signed certificates as trustworthy as anyone could have issued it.
You can make your own cert. To make sure your cert belongs to you (your site) it is signed by authority and the client then may verify that authority (which cetificate is preinstalled in their system) in fact had verified ownership of your site and then signed your cert claims with their private key.
Question, if I can get free valud certs today (there atey sites that give you free ones, I use one for my lemmy site), where’s the security?
I mean it’s secure against man in the middle, but if my site is hacked, no proof is going to prevent the hackers to distribute whatever they want.
Well it stands to reason, that TLS, i.e. Transport-Layer-Security, would secure the transport, and not secure the server providing the service against intrusion.
Also how is your hypothetical related to cost of certificates? If you use an expensive certificate with in person validation of your organization and its ownership of the domain name (these types of certs exist), then how does that change the case where your site is hacked, compared to the free certificate?
Certificates are to protect against MitM attacks, not prevent your site from getting hacked. You need to secure everything, this is one aspect of it
So why can’t I make my own cert? Give the caller my public key and on we go.
You can distribute your public key, and have people manually add it to their trust stores.
But OSs and browsers ship with preloaded trusted certificates. This way, the owner of a preloaded trusted certificate can issue new certificates that are automatically trusted by people’s OSs and browsers.
To become a preloaded trusted certificate owner, I imagine that there are stringent audits and security requirements. Part of that will be verifying the identity of the requester before issuing them a certificate.
With LetsEncrypt, they either need to talk to a server hosted at the domain to retrieve a token (generated when the request is initiated).
This proves the requester owns/controls the domain and the server (the requester has correctly set up DNS records, and placed the required token on the server). This is HTTP challenge mode.
The other method is by a DNS challenge. The requester adds a TXT record to their nameservers with the token value, letsencrypt then inspects the DNS records for the domain and will issue a cert when it sees the token. This proves the requester owns/controls the domain.
So, proving identity is required (otherwise anyone could generate a trusted cert for any domain). And trusted certificate issuers are required, so people don’t have to constantly import (possibly dodgy) public keys
And how does the client validate that your public key is actually your public key and not some attacker’s?
The idea of having a trusted 3rd party is to ensure that some impartial and trustworthy arbiter can confirm to the client that yes, this certificate is trustworthy, because they issued it to the correct party.
But you can absolutely self-sign a certificate. Works just fine, though not all clients accept self-signed certificates as trustworthy as anyone could have issued it.
You can make your own cert. To make sure your cert belongs to you (your site) it is signed by authority and the client then may verify that authority (which cetificate is preinstalled in their system) in fact had verified ownership of your site and then signed your cert claims with their private key.