Unicode C++

Generate RSA Key and Sign a String

See more RSA Examples

Demonstrates how to generate a new RSA public/private key pair and use it to generate a signature for a string. The (binary) digital signature is returned as a hexidecimalized string. Unicode C++

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

    CkRsaW rsa;

    // Generate a 2048-bit RSA key.
    CkPrivateKeyW privKey;
    success = rsa.GenKey(2048,privKey);

    rsa.UsePrivateKey(privKey);

    // Return the signature in hex.
    rsa.put_EncodingMode(L"hex");

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

    // Sign the SHA256 hash of the string.
    const wchar_t *hexSig = rsa.signStringENC(strData,L"sha256");

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

    // Now verify the signature:
    CkPublicKeyW pubKey;
    privKey.ToPublicKey(pubKey);
    rsa.UsePublicKey(pubKey);

    success = rsa.VerifyStringENC(strData,L"sha256",hexSig);
    if (success == true) {
        wprintf(L"Signature verified!\n");
    }
    else {
        wprintf(L"%s\n",rsa.lastErrorText());
    }

    // Try it with an invalid signature:
    success = rsa.VerifyStringENC(strData,L"sha256",L"not a valid sig");
    if (success == true) {
        wprintf(L"Signature verified!\n");
    }
    else {
        wprintf(L"Signature validation failed!\n");
    }

    // Try it with invalid data:
    success = rsa.VerifyStringENC(L"Not the original data",L"sha256",hexSig);
    if (success == true) {
        wprintf(L"Signature verified!\n");
    }
    else {
        wprintf(L"Signature validation failed!\n");
    }
    }