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

C

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

void ChilkatSample(void)
    {
    BOOL success;
    HCkPrivateKey pkey;
    HCkRsa rsa;
    const char *strData;
    const char *base64Sig;

    success = FALSE;

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

    pkey = CkPrivateKey_Create();

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

    rsa = CkRsa_Create();

    // Import the private key into the RSA component:
    success = CkRsa_UsePrivateKey(rsa,pkey);
    if (success == FALSE) {
        printf("%s\n",CkRsa_lastErrorText(rsa));
        CkPrivateKey_Dispose(pkey);
        CkRsa_Dispose(rsa);
        return;
    }

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

    // The resulting signature will be a Base64 string:
    CkRsa_putEncodingMode(rsa,"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 = "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 = CkRsa_signStringENC(rsa,strData,"md5");

    printf("%s\n",base64Sig);

    printf("Success!\n");


    CkPrivateKey_Dispose(pkey);
    CkRsa_Dispose(rsa);

    }