Why do I get a certificate warning when using Timecard from my browser?
All browsers have a security feature that uses a certificate when visiting a secured site (one whose address starts with 'https'). This certificate describes how to encrypt the data traveling between the web browser and the server for the page(s) that you are viewing, so that no one else can intercept and view that data. Many online services, such as banks, online retail stores, government sites, etc. use this technology to secure data.
Normally, the certificate is 'signed' by what's known as a Certificate Authority ('CA'). The Certificate Authority's role is to confirm that the certificate really does belong to the entity that issued it (for example, that it really is from the bank's site). Once signed by a CA, the browser knows that the certificate is genuinely from the website and proceeds to connect and encrypt the data.
In most cases, certificates will be signed because it will be used by thousands or million of users, and an entity will only need one certificate to be signed by a CA for use on its site. A certificate represents an identity (a company, a person and/or a computer), which is why a CA-signed certificate is "better" than a self-signed one. A trusted identity means that the server is not an impostor.
Billings Pro server uses the same technology for encrypting data between web browsers that access Timecard. During installation, Billings Pro Server will generate its own certificate that will be unique to your installation. However, since getting the certificate signed by a CA would require additional time and costs, the certificate will instead be 'self-signed.'
A 'self-signed' certificate has the same security features as a signed certificate, and will feature the same strong encryption of the data transmitted between the browser and server. Since it is not signed by a CA however, the browser will indicate that is it not signed and could not be verified this is the warning you see from the browser. Accepting the certificate will save it into your browser's settings and will prevent warnings in the future.
More information about this can be found here.