The GNU Debugger, usually called just GDB and named gdb as an executable file, is the standard debugger for the GNU operating system. A debugger is regarded as the best friend of a software programmer. However, its use is not strictly limited to the GNU operating system. It is a portable debugger that runs on many Unix-like systems and works for many programming languages, including Ada, C, C++, Objective-C, Free Pascal, Fortran, Java and partially others. Even though GDB can help you in finding out memory leakage related bugs, but it is not a tool to detect memory leakages. GDB cannot be used for programs that compile with errors and it does not help in fixing those errors.
A digital signature is a mathematical scheme for demonstrating the authenticity of a digital message or documents. A valid digital signature gives a recipient reason to believe that the message was created by a known sender, that the sender cannot deny having sent the message (authentication and non-repudiation), and that the message was not altered in transit (integrity).