To use the Grid, you will need 1) some trust stuff in your web browser (so that you know that sites claiming to be on the Grid are genuine), 2) a certificate (so the Grid knows who you are) and 3) membership of the MICE VO (so the Grid lets you access MICE stuff).
The rest of this page will take you through those in that order.
Resources on the Grid identify themselves using digital certificates - but how do you know that a particular certificate is genuine? User and host certificates must themselves be signed by a "Certification Authority" (CA) that vouches that they are genuine (and which also publishes a list (the "CRL") of its certificates that shouldn't be trusted). Great - but how do you know that the alleged CA certificate is itself genuine? Unfortunately, while Grid resources have a list of the genuine certificates installed, the rest of us don't.
So the first thing you have to do is to go to a site that _is_ trusted (because its CA certificate is already in your web browser), and from there go to the websites of the CAs relevant to MICE, and finally "import into your browser" each CA's "root certificates" and CRL.
CAs relevant to MICE are:
As web browsers all behave differently, it's pretty well impossible to give simple-yet-comprehensive written instructions here. Basically:
You will need to go through this again if you move your certificate to a different web browser. (But you won't need to repeat it if you move it back again)
The basic process is as follows:
Note that if you lose a copy of the certificate you will have to revoke it and get a new one issued, so I suggest avoiding putting it on USB sticks as they're too easy to mislay. You should also never keep it in a browser that other people might have access to, so if you applied from say a shared PC at home then you should keep a separate copy of the .p12 securely filed away on a floppy disk/CD-R and delete it from the browser.
Unfortunately I can't tell you which CA you should use. It can be any of those trusted by the EGEE/LCG Grid (not just the subset listed in section 1): if you're at CERN then use the CERN CA, else there will be a national CA; locate it via the EUGridPMA Map. If you already have a certificate for use with one of the LHC experiments, that should work with MICE too (but you'll still need to go through sections 1, 3 and 4 on this page).
Your CA's website should have detailed guides on how to apply, backup and look after your certificate. Read and follow them carefully, especially any bits about "root certificates". The comprehensive documentation from the UK eScience CA includes material on saving, restoring and generally looking after your certificate, and will usually apply to those from other CAs too.
Your certificate will probably expire after one year - make sure you renew it before it does, otherwise you need to do the whole of this step again. You should get a reminder e-mail about 30 days before.
The procedure is being reviewed; currently you should:
Note that you can use your certificate for all sorts of things, such as encrypting or digitally signing e-mail. To use the Grid, you still need to make your certificate available to the client software.
Some aspects of the Grid are accessed through your web browser; you can use any browser into which you have loaded your certificate and set up the trust relationships as per section 1.
For typical Grid use such as submitting jobs and accessing data, you will need to put your certificate where the command-line Grid clients, such as those installed on heplnw17, can find it. The default location is as usercred.p12 in a subdirectory ~/.globus in your home directory. usercred.p12 should have permissions of 400 and .globus 700.
(Note that some older documentation discusses splitting your certificate into two .pem files at this point. This is not necessary for MICE, unless you need to store the certificate in a non-standard location.)