C++

RSA Sign an Encoded Hash

See more RSA Examples

Demonstrates signing a hash (e.g., SHA256) provided as an encoded string (e.g., base64 or hex). C++

#include <CkCert.h>
#include <CkBinData.h>
#include <CkRsa.h>

void ChilkatSample(void)
    {
    bool success = false;

    //  Assuming the smartcard/USB token is installed with the correct drivers from the manufacturer,
    //  this code can work on multiple platforms including Windows, MacOS, Linux, and iOS.

    //  Chilkat automatically detects and determines the way in which the HSM is used,
    //  which can be by PKCS11, Apple Keychain, Microsoft CNG / Crypto API, or ScMinidriver.

    CkCert cert;

    //  Set the token/smartcard PIN prior to loading.
    cert.put_SmartCardPin("123456");

    //  Specify the certificate by its common name.
    success = cert.LoadFromSmartcard("cn=chilkat-rsa-2048");
    if (success == false) {
        std::cout << cert.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Signing with the private key for this cert: " << cert.subjectCN() << "\r\n";

    //  Create data to be hashed and signed.
    CkBinData bd;
    int i;
    for (i = 0; i <= 100; i++) {
        bd.AppendEncoded("000102030405060708090A0B0C0D0E0F","hex");
    }

    CkRsa rsa;

    //  Use the certificate's private key for signing.
    success = rsa.SetX509Cert(cert,true);
    if (success == false) {
        std::cout << rsa.lastErrorText() << "\r\n";
        return;
    }

    //  We'll first compute the hash and then pass the encoded hash to be signed.
    const char *sha256_base64 = bd.getHash("sha256","base64");
    std::cout << "sha256 hash in base64 format: " << sha256_base64 << "\r\n";

    //  Pass in the base64 hash and return a base64 signature.
    rsa.put_EncodingMode("base64");
    const char *rsaSig_base64 = rsa.signHashENC(sha256_base64,"sha256");
    if (success == false) {
        std::cout << rsa.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "RSA signature as base64: " << rsaSig_base64 << "\r\n";
    }