More DBA job interview questions and answers at
http://dba.fyicenter.com/Interview-Questions/
(Continued from previous question...)
How to Sign Jar Files
In a Java 2 environment, Derby can detect digital signatures on jar files. When attempting to load a class from a signed jar file stored in the database, Derby will verify the validity of the signature.
Note:
The Derby class loader only validates the integrity of the signed jar file and that the certificate has not expired. Derby cannot ascertain whether the validity/identity of declared signer is correct. To validate identity, use a Security Manager (i.e., an implementation of java.lang.SecurityManager).
When loading classes from an application jar file in a Java 2 environment, Derby behaves as follows:
* If the class is signed, Derby will:
o verify that the jar was signed using a X.509 certificate (i.e., can be represented by the class java.security.cert.X509Certificate). If not, throw an exception.
o verify that the digital signature matches the contents of the file. If not, throw an exception.
o check that the set of signing certificates are all valid for the current date and time. If any certificate has expired or is not yet valid, throw an exception.
o pass the array of certificates to the setSigners() method of java.lang.ClassLoader. This allows security managers to obtain the list of signers for a class (using java.lang.Class.getSigners) and then validate the identity of the signers using the services of a Public Key Infrastructure (PKI).
Note:
Derby does not provide a security manager.
(Continued on next question...)
