(Unicode C++) RSA SHA256 Signature using Private Key from Java Keystore

Signs plaintext using RSA SHA256 using a key from a Java keystore.

Duplicatest this code:

KeyStore keystore; // key repository for keys containing signature certificate
String alias; // alias for the certificate in the key repository
String password; // password for the certificate's private key
String plaintext; // text being signed


Signature signature = Signature.getInstance("SHA256withRSA");
signature.initSign((PrivateKey) keystore.getKey(alias, password.toCharArray()));
signature.update(plaintext.getBytes("UTF-8"));
byte[] rsa_text= signature.sign();

Chilkat C/C++ Library Downloads
MS Visual C/C++ Linux/CentOS C/C++ Alpine Linux C/C++ MAC OS X C/C++	armhf/aarch64 C/C++ C++ Builder iOS C/C++ Android C/C++	Solaris C/C++ MinGW C/C++

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

void ChilkatSample(void)
    {
    // This requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkJavaKeyStoreW jks;

    const wchar_t *jksPassword = L"secret";

    // Load the Java keystore from a file.  The JKS file password is used
    // to verify the keyed digest that is found at the very end of the keystore.
    // It verifies that the keystore has not been modified.
    bool success = jks.LoadFile(jksPassword,L"qa_data/jks/sample_secret.jks");
    if (success != true) {
        wprintf(L"%s\n",jks.lastErrorText());
        return;
    }

    // Get the private key from the JKS.
    // The private key password may be different than the file password.
    const wchar_t *privKeyPassword = L"secret";
    bool caseSensitive = false;
    CkPrivateKeyW *privKey = jks.FindPrivateKey(privKeyPassword,L"some.alias",caseSensitive);
    if (jks.get_LastMethodSuccess() != true) {
        wprintf(L"%s\n",jks.lastErrorText());
        return;
    }

    // Establish the RSA object and tell it to use the private key..
    CkRsaW rsa;

    success = rsa.ImportPrivateKeyObj(*privKey);
    delete privKey;
    if (success != true) {
        wprintf(L"%s\n",rsa.lastErrorText());
        return;
    }

    // Indicate we'll be signing the utf-8 byte representation of the string..
    rsa.put_Charset(L"utf-8");

    // Sign some plaintext using RSA-SHA256
    CkByteData binarySignature;
    const wchar_t *plaintext = L"this is the text to be signed";
    success = rsa.SignString(plaintext,L"SHA256",binarySignature);
    if (rsa.get_LastMethodSuccess() != true) {
        wprintf(L"%s\n",rsa.lastErrorText());
        return;
    }

    // Alternatively, if the signature is desired in some encoded string form,
    // such as base64, base64-url, hex, etc.
    rsa.put_EncodingMode(L"base64-url");
    const wchar_t *signatureStr = rsa.signStringENC(plaintext,L"SHA256");
    wprintf(L"base64-url RSA signature: %s\n",signatureStr);
    }