Unicode C++

RSA Signature/Verify with .key and .cer

See more RSA Examples

Demonstrates how to use a .key file (private key) and digital certificate (.cer, public key) to create and verify an RSA signature. Unicode C++

#include <CkPrivateKeyW.h>
#include <CkRsaW.h>
#include <CkCertW.h>
#include <CkPublicKeyW.h>

void ChilkatSample(void)
    {
    bool success = false;

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkPrivateKeyW privKey;

    // Load the private key from an RSA .key file:
    success = privKey.LoadPemFile(L"privateKey.key");
    if (success == false) {
        wprintf(L"%s\n",privKey.lastErrorText());
        return;
    }

    CkRsaW rsa;

    // Import the private key into the RSA component:
    success = rsa.UsePrivateKey(privKey);
    if (success == false) {
        wprintf(L"%s\n",rsa.lastErrorText());
        return;
    }

    // Create the signature as a hex string:
    rsa.put_EncodingMode(L"hex");

    const wchar_t *strData = L"This is the string to be signed.";

    // Sign the string using the sha256 hash algorithm.
    // Other valid choices are "md2", "sha1", "sha384",
    // "sha512", and "md5".
    const wchar_t *hexSig = rsa.signStringENC(strData,L"sha256");

    wprintf(L"%s\n",hexSig);

    // Load a digital certificate from a .cer file:
    CkCertW cert;

    success = cert.LoadFromFile(L"myCert.cer");
    if (success == false) {
        wprintf(L"%s\n",cert.lastErrorText());
        return;
    }

    CkPublicKeyW pubKey;
    cert.GetPublicKey(pubKey);

    // Now verify using a new instance of the RSA object:
    CkRsaW rsa2;

    // Import the public key into the RSA object:
    success = rsa2.UsePublicKey(pubKey);
    if (success == false) {
        wprintf(L"%s\n",rsa2.lastErrorText());
        return;
    }

    // The signature is a hex string, so make sure the EncodingMode is correct:
    rsa2.put_EncodingMode(L"hex");

    // Verify the signature:
    success = rsa2.VerifyStringENC(strData,L"sha256",hexSig);
    if (success == false) {
        wprintf(L"%s\n",rsa2.lastErrorText());
        return;
    }

    wprintf(L"Success.\n");
    }