(MFC) RSA Encrypt RSA/ECB/OAEPWithSHA1AndMGF1Padding

Demonstrates how to RSA encrypt using RSA/ECB/OAEPWithSHA1AndMGF1Padding. Also demonstrates RSA/ECB/OAEPWithSHA-256AndMGF1Padding. Both of these terms are from Java's JCE. Note: In this context, "ECB" doesn't actually mean anything. It's a symmetric cipher mode that doesn't apply (or make sense) in this context.

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkRsa.h>
#include <CkPublicKey.h>
#include <CkPrivateKey.h>

void ChilkatSample(void)
    {
    CkString strOut;

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

    CkRsa rsa;

    // First load a public key object with a public key.
    // In this case, we'll load it from a file.
    CkPublicKey pubkey;
    bool success = pubkey.LoadFromFile("qa_data/pem/rsa_public.pem");
    if (success != true) {
        strOut.append(pubkey.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // RSA encryption is limited to small amounts of data. The limit
    // is typically a few hundred bytes and is based on the key size and
    // padding (OAEP vs. PKCS1_5).  RSA encryption is typically used for
    // encrypting hashes or symmetric (bulk encryption algorithm) secret keys.
    const char *plainText = "Time is an illusion. Lunchtime doubly so.";

    // Import the public key to be used for encrypting.
    success = rsa.ImportPublicKeyObj(pubkey);

    // To get OAEP padding, set the OaepPadding property:
    rsa.put_OaepPadding(true);

    // To use SHA1 or SHA-256, set the OaepHash property
    rsa.put_OaepHash("sha256");
    // for SHA1 --
    rsa.put_OaepHash("sha1");

    // Indicate we'll want hex output
    rsa.put_EncodingMode("hex");

    // Encrypt..
    bool usePrivateKey = false;
    const char *encryptedStr = rsa.encryptStringENC(plainText,usePrivateKey);
    strOut.append(encryptedStr);
    strOut.append("\r\n");

    // -------------------------------------------------
    // Now decrypt with the matching private key.
    CkRsa rsa2;

    CkPrivateKey privKey;
    success = privKey.LoadEncryptedPem("qa_data/pem/rsa_passwd.pem","passwd");
    if (success != true) {
        strOut.append(privKey.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    success = rsa2.ImportPrivateKeyObj(privKey);

    // Make sure we have the same settings used for encryption.
    rsa2.put_OaepPadding(true);
    rsa2.put_EncodingMode("hex");
    rsa2.put_OaepHash("sha1");

    const char *originalStr = rsa2.decryptStringENC(encryptedStr,true);

    strOut.append(originalStr);
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }