Q:

Can I use these Certificates with the FileConnection stuff?

In my code there are calls to the FileConnection methods ( open , create , mkdir , delete ) ; so when launching the application then there are questions asking me that the application wants to read files from the device. So I searched inside the phone which I am working with if there are certificates for signing the application then I found these certificates under the Java directory. Here are the "Trusted certificates" listed :
Issuer:
C=US; O=VeriSign, Inc.; OU=Class 3 Public Primary Certification Authority - G2
Not valid before:5/19/1998
Valid not after: 8/2/2028
Domain:thirdparty

Issuer:
C=US; O=VeriSign, Inc.; OU=Class 4 Public Primary Certification Authority - G2
Not valid before:5/19/1998
Valid not after: 8/2/2028
Domain:thirdparty

Issuer:
CN=VeriSign Class 3 Public Primary Certification Authority - G3; C=US; O=Verisign,
Inc.; OU=Verisign Trust Network
Not valid before:10/2/1999
Valid not after: 7/17/2036
Domain:thirdparty

Issuer:
CN=VeriSign Class 4 Public Primary Certification Authority - G3; C=US; O=Verisign,
Inc.; OU=Verisign Trust Network
Not valid before:10/2/1999
Valid not after: 7/17/2036
Domain:thirdparty

Issuer:
C=US; O=VeriSign, Inc.; OU=Class 1 Public Primary Certification Authority
Not valid before:1/30/1996
Valid not after: 8/2/2028
Domain:thirdparty

Issuer:
C=US; O=VeriSign, Inc.; OU=Class 2 Public Primary Certification Authority
Not valid before:1/30/1996
Valid not after: 8/2/2028
Domain:thirdparty

Issuer:
C=US; O=VeriSign, Inc.; OU=Class 3 Public Primary Certification Authority
Not valid before:1/30/1996
Valid not after: 8/2/2028
Domain:thirdparty

Issuer:
CN=alcatel; C=FR; O=a; OU=a
Not valid before:3/11/2004
Valid not after: 3/6/2024
Domain:manufacturer

Issuer:
CN=Thawte Premium Server CA; C=ZA; ST=Western Cape; L=Cape Town; O=Thawte Consulting cc; OU=Certification Services Division; E=premium-server@thawte.com
Not valid before:8/2/1996
Valid not after: 1/1/2021
Domain:thirdparty

Issuer:
CN=Thawte Server CA; C=ZA; ST=Western Cape; L=Cape Town; O=Thawte Consulting cc; OU=Certification Services Division; E=server-certs@thawte.com
Not valid before:8/2/1996
Valid not after: 1/1/2021
Domain:thirdparty

So can I use one of them ? If so how can I use it ?

A:

Those are the root certificates of the certificate authorities installed on your device. You need to sign your code with a code signing certificate from these authorities. Here is a link to verisign http://www.verisign.com/code-signing/sun-java/index.html
Also read about MIDP security.

