If Tomcat is set up for SSL mutual authentication you can get the client javax.servlet.request.X509Certificate from the servlet request.
In the server app I need a key to encrypt a file.
Is it a good idea to use a part of the Client X509Certificate, e.g. the SubjectPublicKeyInfo as encryption key?
The client Certificate should be as secret as any password, shouldn't it?
(this question has Java API example, but is not Java specific)
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Currently I want to expose a gRPC Method as Public API and protected by Auth0 (JWT Token), with Istio(Envoy Proxy) will help validating the token on server side. Since the JWT Token is not encrypted by the standard (it is only used to end-user authentication and authorization layer), I want to encrypt the communication using TLS. Also, my public server already have valid certificate.
The problem is on the gRPC Client side. Every example I look, the gRPC Client have to initialize the TLS Connection with server cert pem file. Is it really necessary? Because it adds operational burden and complexity, where we have to distribute our server pem file everytime we renew the certificate AND/OR the client side has to restart the application.
Thanks,
Agung
If you are using a self signed certificate, then yes you must explicitly trust it in your client. If you use a publicly signed certificate on your Server, gRPC will use the Operating System's certificate authorities to verify the cert. (In the case of Java, it uses the JVMs cert authorities.)
If you are using a self-signed certificate you need to specify the server's root certificates in the pem_root_certs member of the SslCredentialsOptions struct passed in when creating a channel, as Carl says.
However if you are using a CA issued certificate, leaving the pem_root_certs member empty will cause gRPC to default to its own master list (reviewable online), not any OS-specific list.
We have a web server running on linux machine where we configured 'SSLVerifyClient' as 'require' in ssl.conf file.
Does this needs client who is utilizing the service from web browser(like firefox or chrome) needs a certificate.
If yes, then it is not possible to distribute client certificate to every user as there can be some thousands of users, how to overcome this problem.
If no, then how the data passed over network is secure? I know that certificate helps in encrypting data so that no one who don't have certificate can read data.
Please help me in clarifying my doubts
If you don't use client certificate, the https connection is still safe:
Only the client and the server can read/write the content
The identity of the server is assured by a certificate authority
Client certificate only give you client authentication in the beginning of the connection. To encrypt the data, the public key of the server is used in the beginning (See public key encryption).
If you identify the client with cookies set after login/password submit, it is still safe: you have identify the client.
When SSLVerifyClient is set to require, the client MUST pass a client certificate. You would generate these via OpenSSL, and sign them with a certificate authority that you install via SSLCACertificateFile.
How you distribute those certificates is an issue you'll have to solve yourself.
Why a service certificate is required when non-windows client credential specified ?
(i found some specifications on the book said that, a service certificate can be used to negotiate a symmetric key for messaging encryption and signing when negotiation is enabled, but if negotiation is disabled, the client must reference the certificate in the store or including the BASE64 encoded public key, it comes out another question as below)
when the negotiation is disabled, definitely the service certificate will be used for encrypting message, because the client knows the public key, but which one will be used for message signing ?
when the transport security is enabled, and the service certificate is also specified, it said that the certificate will be used for negotiate a SSL session key for message signing and encryption, it applied to all the bindings ,such as HTTP, TCP, etc.
when we are using the windows client credentials, which one will be used for message encryption and signing?
thanks.
IF you choose to authentucate the client you can choose between windows credentials, username, certificate or SAML token. If windows auth is not available you need some other mechanism.
As for the other questions please be more specific. In general client will generate a temporary key (session key) which will be used to encrypt the message. Server certificate will encrypt the session key.
I am somewhat confused as to how two-way SSL works. How does the client create its certificate to send to the server? Is it generated from the server and distributed to the client?
Also, what is the advantage of two-way SSL over one-way SSL?
Both certificates should exist prior to the connection. They're usually created by Certification Authorities (not necessarily the same). (There are alternative cases where verification can be done differently, but some verification will need to be made.)
The server certificate should be created by a CA that the client trusts (and following the naming conventions defined in RFC 6125).
The client certificate should be created by a CA that the server trusts.
It's up to each party to choose what it trusts.
There are online CA tools that will allow you to apply for a certificate within your browser and get it installed there once the CA has issued it. They need not be on the server that requests client-certificate authentication.
The certificate distribution and trust management is the role of the Public Key Infrastructure (PKI), implemented via the CAs. The SSL/TLS client and servers and then merely users of that PKI.
When the client connects to a server that requests client-certificate authentication, the server sends a list of CAs it's willing to accept as part of the client-certificate request. The client is then able to send its client certificate, if it wishes to and a suitable one is available.
The main advantages of client-certificate authentication are:
The private information (the private key) is never sent to the server. The client doesn't let its secret out at all during the authentication.
A server that doesn't know a user with that certificate can still authenticate that user, provided it trusts the CA that issued the certificate (and that the certificate is valid). This is very similar to the way passports are used: you may have never met a person showing you a passport, but because you trust the issuing authority, you're able to link the identity to the person.
You may be interested in Advantages of client certificates for client authentication? (on Security.SE).
What you call "Two-Way SSL" is usually called TLS/SSL with client certificate authentication.
In a "normal" TLS connection to example.com only the client verifies that it is indeed communicating with the server for example.com. The server doesn't know who the client is. If the server wants to authenticate the client the usual thing is to use passwords, so a client needs to send a user name and password to the server, but this happens inside the TLS connection as part of an inner protocol (e.g. HTTP) it's not part of the TLS protocol itself. The disadvantage is that you need a separate password for every site because you send the password to the server. So if you use the same password on for example PayPal and MyPonyForum then every time you log into MyPonyForum you send this password to the server of MyPonyForum so the operator of this server could intercept it and try it on PayPal and can issue payments in your name.
Client certificate authentication offers another way to authenticate the client in a TLS connection. In contrast to password login, client certificate authentication is specified as part of the TLS protocol. It works analogous to the way the client authenticates the server: The client generates a public private key pair and submits the public key to a trusted CA for signing. The CA returns a client certificate that can be used to authenticate the client. The client can now use the same certificate to authenticate to different servers (i.e. you could use the same certificate for PayPal and MyPonyForum without risking that it can be abused). The way it works is that after the server has sent its certificate it asks the client to provide a certificate too. Then some public key magic happens (if you want to know the details read RFC 5246) and now the client knows it communicates with the right server, the server knows it communicates with the right client and both have some common key material to encrypt and verify the connection.
In two way ssl the client asks for servers digital certificate and server ask for the same from the client. It is more secured as it is both ways, although its bit slow. Generally we dont follow it as the server doesnt care about the identity of the client, but a client needs to make sure about the integrity of server it is connecting to.
I have some simple questions that i can't get a direct answer in any site because the variety of options in this subject.
In Message Level Security, is mandatory for the client to have an installed certificate? I assume this because the server should encrypt the response message with the client Public Key and then the client decrypt it with his own Private Key.
Is any alternative to not have the certificate in the client and have the messages encrypted in both ways(client->server) and (server->client)?
You can have message security without the client authenticating at all. You only need a client cert if the client is authenticating via certificates
The server cert is used for securing the message in the first case. The client encrypts with the public key of the server and the server can then decrypt with its private key
If you are using secure conversation then the server cert is just used to bootstrap a session key which is then used for encryption/decryption
As long as the server cert has a full chain of trust in the client then there is no need to install the server cert on the client either