Which Linux command will securely delete a file by overwriting its contents?

Shayla is designing a web-based application that will pass data to and from a company extranet.
This data is very sensitive and must be protected at all costs. Shayla will use a digital certificate
and a digital signature to protect the data. The digital signature she has chosen to use is based on
the difficulty in computing discrete logarithms. Which digital signature has she chosen?

After learning from an external auditor that his code was susceptible to attack, George decided to
rewrite some of his code to look like the following. What is George preventing by changing the
code?
public voif doContent(…) {
…
String s;
if ((s = getUsernameByID(“userid”)) != null) {
s = StringUtils.encodeToHTML(s, 50);
response.write(“<br>Applicant:<u>” + s +
“</u>”);
}
…
}

Fred is planning on using the windows socket application ClientApp.exe program to create a
client-side application that his employees will use. This program will access backend programs
from two different remote sites over WAN connections. If Fred does not make any modifications to
the ClientApp.exe default settings, what port must he have the network engineer open in order for
the application to communicate?

What would be the result of the following code?
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
char *input=malloc(20);
char *output=malloc(20);
strcpy(output, “normal output”);
strcpy(input, argv[1]);

printf(“input at %p: %s\n”, input, input);
printf(“output at %p: %s\n”, output, output);
printf(“\n\n%s\n”, output);
}