(C) RSA Signature SHA256withRSA, iso-8859-1, base64

See more RSA Examples

RSA sign the iso-8859-1 byte representation of a string with SHA256withRSA, and return the signature in the base64 encoding.

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#include <C_CkPrivateKey.h>
#include <C_CkRsa.h>

void ChilkatSample(void)
    {
    HCkPrivateKey privKey;
    BOOL success;
    HCkRsa rsa;
    const char *originalData;
    const char *sigBase64;

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // This example will duplicate the following Java code:
    // 
    // Signature sign = Signature.getInstance("SHA256withRSA");
    // sign.initSign(privateKey);
    // sign.update(original.getBytes(Charset.forName("ISO-8859-1")));
    // 
    // ...
    // byte[] resultado = sign.sign();
    // sello = encodeByteArrayToBase64(resultado);
    // 

    // Load an RSA private key for signing.
    // You can load any format file.  This example loads a .pem, but you can provide path to any type of file holding a private key.
    privKey = CkPrivateKey_Create();
    success = CkPrivateKey_LoadAnyFormatFile(privKey,"qa_data/pem/rsa_passwd.pem","passwd");
    if (success != TRUE) {
        printf("%s\n",CkPrivateKey_lastErrorText(privKey));
        CkPrivateKey_Dispose(privKey);
        return;
    }

    rsa = CkRsa_Create();
    CkRsa_ImportPrivateKeyObj(rsa,privKey);

    originalData = "This is the string to be hashed an RSA signed.";

    // Indicate that we want the iso-8859-1 byte representation of the string to be signed
    CkRsa_putCharset(rsa,"iso-8859-1");

    // We want the RSA signature in base64 format
    CkRsa_putEncodingMode(rsa,"base64");

    sigBase64 = CkRsa_signStringENC(rsa,originalData,"sha256");
    printf("%s\n",sigBase64);


    CkPrivateKey_Dispose(privKey);
    CkRsa_Dispose(rsa);

    }