C++ Blob::front方法代码示例

Blob SqliteStatement::getBlob (int column)
{
    int size = sqlite3_column_bytes (statement, column);
    Blob ret (size);
    memcpy (& (ret.front ()), sqlite3_column_blob (statement, column), size);
    return ret;
}

static ECIES_HMAC_TYPE makeHMAC (const ECIES_HMAC_KEY_TYPE& secret, Blob const& data)
{
    HMAC_CTX ctx;
    HMAC_CTX_init (&ctx);

    if (HMAC_Init_ex (&ctx, secret.begin (), ECIES_HMAC_KEY_SIZE, ECIES_HMAC_ALGO, nullptr) != 1)
    {
        HMAC_CTX_cleanup (&ctx);
        throw std::runtime_error ("init hmac");
    }

    if (HMAC_Update (&ctx, & (data.front ()), data.size ()) != 1)
    {
        HMAC_CTX_cleanup (&ctx);
        throw std::runtime_error ("update hmac");
    }

    ECIES_HMAC_TYPE ret;
    unsigned int ml = ECIES_HMAC_SIZE;

    if (HMAC_Final (&ctx, ret.begin (), &ml) != 1)
    {
        HMAC_CTX_cleanup (&ctx);
        throw std::runtime_error ("finalize hmac");
    }

    assert (ml == ECIES_HMAC_SIZE);
    HMAC_CTX_cleanup (&ctx);

    return ret;
}

bool checkECIES (void)
{
    CKey senderPriv, recipientPriv, senderPub, recipientPub;

    for (int i = 0; i < 30000; ++i)
    {
        if ((i % 100) == 0)
        {
            // generate new keys every 100 times
            //          Log::out() << "new keys";
            senderPriv.MakeNewKey ();
            recipientPriv.MakeNewKey ();

            if (!senderPub.SetPubKey (senderPriv.GetPubKey ()))
                throw std::runtime_error ("key error");

            if (!recipientPub.SetPubKey (recipientPriv.GetPubKey ()))
                throw std::runtime_error ("key error");
        }

        // generate message
        Blob message (4096);
        int msglen = i % 3000;

        RandomNumbers::getInstance ().fillBytes (&message.front (), msglen);
        message.resize (msglen);

        // encrypt message with sender's private key and recipient's public key
        Blob ciphertext = senderPriv.encryptECIES (recipientPub, message);

        // decrypt message with recipient's private key and sender's public key
        Blob decrypt = recipientPriv.decryptECIES (senderPub, ciphertext);

        if (decrypt != message)
        {
            assert (false);
            return false;
        }

        //Log::out() << "Msg(" << msglen << ") ok " << ciphertext.size();
    }

    return true;
}

Blob decryptECIES (const openssl::ec_key& secretKey, const openssl::ec_key& publicKey, Blob const& ciphertext)
{
    // minimum ciphertext = IV + HMAC + 1 block
    if (ciphertext.size () < ((2 * ECIES_ENC_BLK_SIZE) + ECIES_HMAC_SIZE) )
        throw std::runtime_error ("ciphertext too short");

    // extract IV
    ECIES_ENC_IV_TYPE iv;
    memcpy (iv.begin (), & (ciphertext.front ()), ECIES_ENC_BLK_SIZE);

    // begin decrypting
    EVP_CIPHER_CTX ctx;
    EVP_CIPHER_CTX_init (&ctx);

    ECIES_ENC_KEY_TYPE secret;
    ECIES_HMAC_KEY_TYPE hmacKey;
    getECIESSecret (secretKey, publicKey, secret, hmacKey);

    if (EVP_DecryptInit_ex (&ctx, ECIES_ENC_ALGO, nullptr, secret.begin (), iv.begin ()) != 1)
    {
        secret.zero ();
        hmacKey.zero ();
        EVP_CIPHER_CTX_cleanup (&ctx);
        throw std::runtime_error ("unable to init cipher");
    }

    // decrypt mac
    ECIES_HMAC_TYPE hmac;
    int outlen = ECIES_HMAC_SIZE;

    if ( (EVP_DecryptUpdate (&ctx, hmac.begin (), &outlen,
                             & (ciphertext.front ()) + ECIES_ENC_BLK_SIZE, ECIES_HMAC_SIZE + 1) != 1) || (outlen != ECIES_HMAC_SIZE) )
    {
        secret.zero ();
        hmacKey.zero ();
        EVP_CIPHER_CTX_cleanup (&ctx);
        throw std::runtime_error ("unable to extract hmac");
    }

    // decrypt plaintext (after IV and encrypted mac)
    Blob plaintext (ciphertext.size () - ECIES_HMAC_SIZE - ECIES_ENC_BLK_SIZE);
    outlen = plaintext.size ();

    if (EVP_DecryptUpdate (&ctx, & (plaintext.front ()), &outlen,
                           & (ciphertext.front ()) + ECIES_ENC_BLK_SIZE + ECIES_HMAC_SIZE + 1,
                           ciphertext.size () - ECIES_ENC_BLK_SIZE - ECIES_HMAC_SIZE - 1) != 1)
    {
        secret.zero ();
        hmacKey.zero ();
        EVP_CIPHER_CTX_cleanup (&ctx);
        throw std::runtime_error ("unable to extract plaintext");
    }

    // decrypt padding
    int flen = 0;

    if (EVP_DecryptFinal (&ctx, & (plaintext.front ()) + outlen, &flen) != 1)
    {
        secret.zero ();
        hmacKey.zero ();
        EVP_CIPHER_CTX_cleanup (&ctx);
        throw std::runtime_error ("plaintext had bad padding");
    }

    plaintext.resize (flen + outlen);

    // verify integrity
    if (hmac != makeHMAC (hmacKey, plaintext))
    {
        secret.zero ();
        hmacKey.zero ();
        EVP_CIPHER_CTX_cleanup (&ctx);
        throw std::runtime_error ("plaintext had bad hmac");
    }

    secret.zero ();
    hmacKey.zero ();

    EVP_CIPHER_CTX_cleanup (&ctx);
    return plaintext;
}

Blob encryptECIES (const openssl::ec_key& secretKey, const openssl::ec_key& publicKey, Blob const& plaintext)
{

    ECIES_ENC_IV_TYPE iv;
    random_fill (iv.begin (), ECIES_ENC_BLK_SIZE);

    ECIES_ENC_KEY_TYPE secret;
    ECIES_HMAC_KEY_TYPE hmacKey;

    getECIESSecret (secretKey, publicKey, secret, hmacKey);
    ECIES_HMAC_TYPE hmac = makeHMAC (hmacKey, plaintext);
    hmacKey.zero ();

    EVP_CIPHER_CTX ctx;
    EVP_CIPHER_CTX_init (&ctx);

    if (EVP_EncryptInit_ex (&ctx, ECIES_ENC_ALGO, nullptr, secret.begin (), iv.begin ()) != 1)
    {
        EVP_CIPHER_CTX_cleanup (&ctx);
        secret.zero ();
        throw std::runtime_error ("init cipher ctx");
    }

    secret.zero ();

    Blob out (plaintext.size () + ECIES_HMAC_SIZE + ECIES_ENC_KEY_SIZE + ECIES_ENC_BLK_SIZE, 0);
    int len = 0, bytesWritten;

    // output IV
    memcpy (& (out.front ()), iv.begin (), ECIES_ENC_BLK_SIZE);
    len = ECIES_ENC_BLK_SIZE;

    // Encrypt/output HMAC
    bytesWritten = out.capacity () - len;
    assert (bytesWritten > 0);

    if (EVP_EncryptUpdate (&ctx, & (out.front ()) + len, &bytesWritten, hmac.begin (), ECIES_HMAC_SIZE) < 0)
    {
        EVP_CIPHER_CTX_cleanup (&ctx);
        throw std::runtime_error ("");
    }

    len += bytesWritten;

    // encrypt/output plaintext
    bytesWritten = out.capacity () - len;
    assert (bytesWritten > 0);

    if (EVP_EncryptUpdate (&ctx, & (out.front ()) + len, &bytesWritten, & (plaintext.front ()), plaintext.size ()) < 0)
    {
        EVP_CIPHER_CTX_cleanup (&ctx);
        throw std::runtime_error ("");
    }

    len += bytesWritten;

    // finalize
    bytesWritten = out.capacity () - len;

    if (EVP_EncryptFinal_ex (&ctx, & (out.front ()) + len, &bytesWritten) < 0)
    {
        EVP_CIPHER_CTX_cleanup (&ctx);
        throw std::runtime_error ("encryption error");
    }

    len += bytesWritten;

    // Output contains: IV, encrypted HMAC, encrypted data, encrypted padding
    assert (len <= (plaintext.size () + ECIES_HMAC_SIZE + (2 * ECIES_ENC_BLK_SIZE)));
    assert (len >= (plaintext.size () + ECIES_HMAC_SIZE + ECIES_ENC_BLK_SIZE)); // IV, HMAC, data
    out.resize (len);
    EVP_CIPHER_CTX_cleanup (&ctx);
    return out;
}

int SqliteStatement::bindStatic (int position, Blob const& value)
{
    return sqlite3_bind_blob (statement, position, &value.front (), value.size (), SQLITE_STATIC);
}