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 <C_CkCert.h>
#include <C_CkBinData.h>
#include <C_CkRsa.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkCert cert;
    HCkBinData bd;
    int i;
    HCkRsa rsa;
    const char *sha256_base64;
    const char *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 = CkCert_Create();

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

    //  Specify the certificate by its common name.
    success = CkCert_LoadFromSmartcard(cert,"cn=chilkat-rsa-2048");
    if (success == FALSE) {
        printf("%s\n",CkCert_lastErrorText(cert));
        CkCert_Dispose(cert);
        return;
    }

    printf("Signing with the private key for this cert: %s\n",CkCert_subjectCN(cert));

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

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

    rsa = CkRsa_Create();

    //  Use the certificate's private key for signing.
    success = CkRsa_SetX509Cert(rsa,cert,TRUE);
    if (success == FALSE) {
        printf("%s\n",CkRsa_lastErrorText(rsa));
        CkCert_Dispose(cert);
        CkBinData_Dispose(bd);
        CkRsa_Dispose(rsa);
        return;
    }

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

    //  Pass in the base64 hash and return a base64 signature.
    CkRsa_putEncodingMode(rsa,"base64");
    rsaSig_base64 = CkRsa_signHashENC(rsa,sha256_base64,"sha256");
    if (success == FALSE) {
        printf("%s\n",CkRsa_lastErrorText(rsa));
        CkCert_Dispose(cert);
        CkBinData_Dispose(bd);
        CkRsa_Dispose(rsa);
        return;
    }

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


    CkCert_Dispose(cert);
    CkBinData_Dispose(bd);
    CkRsa_Dispose(rsa);

    }