Unicode C

Duplicate openssl dgst -md5 -sign myKey.pem something.txt | openssl enc -base64 -A

See more RSA Examples

Demonstrates how to duplicate the creation of an RSA signature produced by this OpenSSL command:

openssl dgst -md5 -sign myKey.pem something.txt | openssl enc -base64 -A

Unicode C

#include <C_CkPrivateKeyW.h>
#include <C_CkRsaW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkPrivateKeyW pkey;
    HCkRsaW rsa;
    const wchar_t *strData;
    const wchar_t *base64Sig;

    success = FALSE;

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

    pkey = CkPrivateKeyW_Create();

    // Load the private key from an RSA PEM file:
    success = CkPrivateKeyW_LoadPemFile(pkey,L"myKey.pem");

    rsa = CkRsaW_Create();

    // Import the private key into the RSA component:
    success = CkRsaW_UsePrivateKey(rsa,pkey);
    if (success == FALSE) {
        wprintf(L"%s\n",CkRsaW_lastErrorText(rsa));
        CkPrivateKeyW_Dispose(pkey);
        CkRsaW_Dispose(rsa);
        return;
    }

    // OpenSSL uses BigEndian byte ordering:
    CkRsaW_putLittleEndian(rsa,FALSE);

    // The resulting signature will be a Base64 string:
    CkRsaW_putEncodingMode(rsa,L"base64");

    // For simplicity, we're not loading
    // the data to be signed from a file.  We are instead simply
    // using a literal string value.  
    strData = L"This is the text to be signed.";

    // Hash the input using MD5, and then sign the hash:
    // Other valid hash algorithm choices are "md2" and "sha-1".
    base64Sig = CkRsaW_signStringENC(rsa,strData,L"md5");

    wprintf(L"%s\n",base64Sig);

    wprintf(L"Success!\n");


    CkPrivateKeyW_Dispose(pkey);
    CkRsaW_Dispose(rsa);

    }