#include <CkCrypt2>
#include <CkDsa.h>
void ChilkatSample(void)
{
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.
CkCrypt2 crypt;
crypt.put_EncodingMode("hex");
crypt.put_HashAlgorithm("sha-1");
// Return the SHA-1 hash of a file. The file may be any size.
// The Chilkat Crypt component will stream the file when
// computing the hash, keeping the memory usage constant
// and reasonable.
// The 20-byte SHA-1 hash is returned as a hex-encoded string.
const char *hashStr = crypt.hashFileENC("hamlet.xml");
CkDsa dsa;
// Load a DSA private key from a PEM file. Chilkat DSA
// provides the ability to load and save DSA public and private
// keys from encrypted or non-encrypted PEM or DER.
// The LoadText method is for convenience only. You may
// use any means to load the contents of a PEM file into
// a string.
const char *pemPrivateKey = 0;
pemPrivateKey = dsa.loadText("dsa_priv.pem");
bool success = dsa.FromPem(pemPrivateKey);
if (success != true) {
std::cout << dsa.lastErrorText() << "\r\n";
return;
}
// You may optionally verify the key to ensure that it is a valid
// DSA key.
success = dsa.VerifyKey();
if (success != true) {
std::cout << dsa.lastErrorText() << "\r\n";
return;
}
// Load the hash to be signed into the DSA object:
success = dsa.SetEncodedHash("hex",hashStr);
if (success != true) {
std::cout << dsa.lastErrorText() << "\r\n";
return;
}
// Now that the DSA object contains both the private key and hash,
// it is ready to create the signature:
success = dsa.SignHash();
if (success != true) {
std::cout << dsa.lastErrorText() << "\r\n";
return;
}
// If SignHash is successful, the DSA object contains the
// signature. It may be accessed as a hex or base64 encoded
// string. (It is also possible to access directly in byte array form via
// the "Signature" property.)
const char *hexSig = dsa.getEncodedSignature("hex");
std::cout << "Signature:" << "\r\n";
std::cout << hexSig << "\r\n";
// -----------------------------------------------------------
// Step 2: Verify the DSA Signature
// -----------------------------------------------------------
CkDsa dsa2;
// Load the DSA public key to be used for verification:
const char *pemPublicKey = 0;
pemPublicKey = dsa2.loadText("dsa_pub.pem");
success = dsa2.FromPublicPem(pemPublicKey);
if (success != true) {
std::cout << dsa2.lastErrorText() << "\r\n";
return;
}
// Load the hash to be verified against the signature.
success = dsa2.SetEncodedHash("hex",hashStr);
if (success != true) {
std::cout << dsa2.lastErrorText() << "\r\n";
return;
}
// Load the signature:
success = dsa2.SetEncodedSignature("hex",hexSig);
if (success != true) {
std::cout << dsa2.lastErrorText() << "\r\n";
return;
}
// Verify:
success = dsa2.Verify();
if (success != true) {
std::cout << dsa2.lastErrorText() << "\r\n";
}
else {
std::cout << "DSA Signature Verified!" << "\r\n";
}
}
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OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.
#include <iostream>
#include <string>
using namespace std;
int main()
{
string name;
cout << "Enter name:";
getline (cin, name);
cout << "Hello " << name;
return 0;
}
C++ is a widely used middle-level programming language.
When ever you want to perform a set of operations based on a condition If-Else is used.
if(conditional-expression) {
//code
}
else {
//code
}
You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.
Switch is an alternative to If-Else-If ladder.
switch(conditional-expression){
case value1:
// code
break; // optional
case value2:
// code
break; // optional
......
default:
code to be executed when all the above cases are not matched;
}
For loop is used to iterate a set of statements based on a condition.
for(Initialization; Condition; Increment/decrement){
//code
}
While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.
while (condition) {
// code
}
Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.
do {
// code
} while (condition);
Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.
return_type function_name(parameters);
function_name (parameters)
return_type function_name(parameters) {
// code
}