Unicode 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). Unicode C

#include <C_CkCertW.h>
#include <C_CkBinDataW.h>
#include <C_CkRsaW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkCertW cert;
    HCkBinDataW bd;
    int i;
    HCkRsaW rsa;
    const wchar_t *sha256_base64;
    const wchar_t *rsaSig_base64;

    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.

    cert = CkCertW_Create();

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

    //  Specify the certificate by its common name.
    success = CkCertW_LoadFromSmartcard(cert,L"cn=chilkat-rsa-2048");
    if (success == FALSE) {
        wprintf(L"%s\n",CkCertW_lastErrorText(cert));
        CkCertW_Dispose(cert);
        return;
    }

    wprintf(L"Signing with the private key for this cert: %s\n",CkCertW_subjectCN(cert));

    //  Create data to be hashed and signed.
    bd = CkBinDataW_Create();

    for (i = 0; i <= 100; i++) {
        CkBinDataW_AppendEncoded(bd,L"000102030405060708090A0B0C0D0E0F",L"hex");
    }

    rsa = CkRsaW_Create();

    //  Use the certificate's private key for signing.
    success = CkRsaW_SetX509Cert(rsa,cert,TRUE);
    if (success == FALSE) {
        wprintf(L"%s\n",CkRsaW_lastErrorText(rsa));
        CkCertW_Dispose(cert);
        CkBinDataW_Dispose(bd);
        CkRsaW_Dispose(rsa);
        return;
    }

    //  We'll first compute the hash and then pass the encoded hash to be signed.
    sha256_base64 = CkBinDataW_getHash(bd,L"sha256",L"base64");
    wprintf(L"sha256 hash in base64 format: %s\n",sha256_base64);

    //  Pass in the base64 hash and return a base64 signature.
    CkRsaW_putEncodingMode(rsa,L"base64");
    rsaSig_base64 = CkRsaW_signHashENC(rsa,sha256_base64,L"sha256");
    if (success == FALSE) {
        wprintf(L"%s\n",CkRsaW_lastErrorText(rsa));
        CkCertW_Dispose(cert);
        CkBinDataW_Dispose(bd);
        CkRsaW_Dispose(rsa);
        return;
    }

    wprintf(L"RSA signature as base64: %s\n",rsaSig_base64);


    CkCertW_Dispose(cert);
    CkBinDataW_Dispose(bd);
    CkRsaW_Dispose(rsa);

    }