[HELP] AES CBC & ECB Encryption & Decryption

[nemoryoliver]

I am very new to QT and also with Encryption stuffs. Just a week I started fighting to learn encryption stuffs but I am really stuck and don't know what to do.

I just really need to decrypt a downloaded blob. using ECB and also there's another I need with CBC

Here's the working PHP functions I want to convert to QT

function decryptECB($data) 
{
	$BLOB_ENCRYPTION_KEY 	= 'M02cnQ51Ji97vwT4';
	return mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $BLOB_ENCRYPTION_KEY, pad($data), MCRYPT_MODE_ECB);
}
 
function encryptECB($data) 
{
	$BLOB_ENCRYPTION_KEY 	= 'M02cnQ51Ji97vwT4';
	return mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $BLOB_ENCRYPTION_KEY, pad($data), MCRYPT_MODE_ECB);
}
 
function pad($data, $blocksize = 16) 
{
	$pad = $blocksize - (strlen($data) % $blocksize);
	return $data . str_repeat(chr($pad), $pad);
}
 
// FOR STORIES
function decryptCBC($data, $key, $iv) 
{
	// Decode the key and IV.
	$iv = base64_decode($iv);
	$key = base64_decode($key);
 
	// Decrypt the data.
	$data = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $data, MCRYPT_MODE_CBC, $iv);
	$padding = ord($data[strlen($data) - 1]);
 
	return substr($data, 0, -$padding);
}

function decryptECB($data) 
{
	$BLOB_ENCRYPTION_KEY 	= 'M02cnQ51Ji97vwT4';
	return mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $BLOB_ENCRYPTION_KEY, pad($data), MCRYPT_MODE_ECB);
}

function encryptECB($data) 
{
	$BLOB_ENCRYPTION_KEY 	= 'M02cnQ51Ji97vwT4';
	return mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $BLOB_ENCRYPTION_KEY, pad($data), MCRYPT_MODE_ECB);
}

function pad($data, $blocksize = 16) 
{
	$pad = $blocksize - (strlen($data) % $blocksize);
	return $data . str_repeat(chr($pad), $pad);
}

// FOR STORIES
function decryptCBC($data, $key, $iv) 
{
	// Decode the key and IV.
	$iv = base64_decode($iv);
	$key = base64_decode($key);

	// Decrypt the data.
	$data = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $data, MCRYPT_MODE_CBC, $iv);
	$padding = ord($data[strlen($data) - 1]);

	return substr($data, 0, -$padding);
}

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I am programming this to the BlackBerry10 Platform

Do you have any suggested libs that has the similar functions as with PHP?

I tried AESCryptoDemo https://github.com/blackberry/Cascad.../AESCryptoDemo and I think it uses CBC which I saw in it's AESParams.cpp file. but no example for ECB

This is how I load downloaded the file in QT

QString filename = "data/files/blobs/storyphoto.jpg";
 
QFile* file = new QFile(filename);
 
if(file->open(QIODevice::ReadOnly))
{
	qDebug() << "BYTES: " + QString::fromAscii(file->readAll()) + ", SIZE: " + file->size();
 
	QString decryptedBlob = decrypt(file->readAll());
 
	qDebug() << "DECRYPTED BLOB: " + toHex(file->readAll());
 
	QFile* newFile = new QFile("data/files/blobs/NEW.jpg");
 
	if (!newFile->open(QIODevice::WriteOnly))
	{
		qDebug() << "PROBLEM OPENING FILE: " + filename;
	}
	else
	{
		newFile->write(decryptedBlob.toAscii());
	}
 
	newFile->close();
}
else
{
	qDebug() << "CANT OPEN: " + filename;
}
 
file->close();
 I have also modified some AESCryptoDemo functions - Just to return values
 
QString ApplicationUI::encrypt(QString data)
{
	QString encryptedData = "";
 
	QByteArray in(data.toUtf8());
	pad(in);
	QByteArray out(in.length(), 0);
 
	if (crypt(true, in, out))
	{
		encryptedData = toHex(out);
	}
 
	return encryptedData;
}
 
QString ApplicationUI::decrypt(QString data)
{
	QString decryptedBlob = "";
 
	QByteArray in;
 
	if (!fromHex(data, in))
	{
		qDebug() << "Cipher text is not valid hex";
		return "";
	}
 
	QByteArray out(in.length(), 0);
 
	if (crypt(false, in, out))
	{
		if (removePadding(out))
		{
			decryptedBlob = QString::fromUtf8(out.constData(), out.length());
		}
	}
 
	return decryptedBlob;
}
 
QString ApplicationUI::toHex(const QByteArray & in)
{
	static char hexChars[] = "0123456789abcdef";
 
	const char * c = in.constData();
	QString toReturn;
 
	for (int i = 0; i < in.length(); ++i)
	{
		toReturn += hexChars[(c[i] >> 4) & 0xf];
		toReturn += hexChars[(c[i]) & 0xf];
	}
 
	return toReturn;
}

QString filename = "data/files/blobs/storyphoto.jpg";

QFile* file = new QFile(filename);

if(file->open(QIODevice::ReadOnly))
{
	qDebug() << "BYTES: " + QString::fromAscii(file->readAll()) + ", SIZE: " + file->size();

	QString decryptedBlob = decrypt(file->readAll());

	qDebug() << "DECRYPTED BLOB: " + toHex(file->readAll());

	QFile* newFile = new QFile("data/files/blobs/NEW.jpg");

	if (!newFile->open(QIODevice::WriteOnly))
	{
		qDebug() << "PROBLEM OPENING FILE: " + filename;
	}
	else
	{
		newFile->write(decryptedBlob.toAscii());
	}

	newFile->close();
}
else
{
	qDebug() << "CANT OPEN: " + filename;
}

file->close();
 I have also modified some AESCryptoDemo functions - Just to return values
 
QString ApplicationUI::encrypt(QString data)
{
	QString encryptedData = "";

	QByteArray in(data.toUtf8());
	pad(in);
	QByteArray out(in.length(), 0);

	if (crypt(true, in, out))
	{
		encryptedData = toHex(out);
	}

	return encryptedData;
}
 
QString ApplicationUI::decrypt(QString data)
{
	QString decryptedBlob = "";

	QByteArray in;

	if (!fromHex(data, in))
	{
		qDebug() << "Cipher text is not valid hex";
		return "";
	}

	QByteArray out(in.length(), 0);

	if (crypt(false, in, out))
	{
		if (removePadding(out))
		{
			decryptedBlob = QString::fromUtf8(out.constData(), out.length());
		}
	}

	return decryptedBlob;
}
 
QString ApplicationUI::toHex(const QByteArray & in)
{
	static char hexChars[] = "0123456789abcdef";

	const char * c = in.constData();
	QString toReturn;

	for (int i = 0; i < in.length(); ++i)
	{
		toReturn += hexChars[(c[i] >> 4) & 0xf];
		toReturn += hexChars[(c[i]) & 0xf];
	}

	return toReturn;
}

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Here I am trying to encrypt and decrypt a simple string..

I also don't think if I need to do something with the char "\" because when I qDebug it it is forgotten.

QString key = "i17ZJekcUf3J\/P\/EFk3fmXHSBnxfMvf6BFuN0kbI57Q=";
QString iv = "wmUlWE+EmUMguG\/ealoMcg==";
 
QString hexKey = toHex(key.toAscii());
QString hexIV = toHex(iv.toAscii());
 
setKey(hexKey);
setIV(hexIV);
 
qDebug() << "HEX KEY: " + hexKey + ", ORIG KEY: " + key;
qDebug() << "HEX IV: " + hexIV + ", ORIG IV: " + iv;
 
QString encrypted = encrypt("data");
QString decrypted = decrypt(encrypted);
 
qDebug() << "ENCRYPTED " + encrypted + ", DECRYPTED: " + decrypted;

QString key = "i17ZJekcUf3J\/P\/EFk3fmXHSBnxfMvf6BFuN0kbI57Q=";
QString iv = "wmUlWE+EmUMguG\/ealoMcg==";

QString hexKey = toHex(key.toAscii());
QString hexIV = toHex(iv.toAscii());

setKey(hexKey);
setIV(hexIV);

qDebug() << "HEX KEY: " + hexKey + ", ORIG KEY: " + key;
qDebug() << "HEX IV: " + hexIV + ", ORIG IV: " + iv;

QString encrypted = encrypt("data");
QString decrypted = decrypt(encrypted);

qDebug() << "ENCRYPTED " + encrypted + ", DECRYPTED: " + decrypted;

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running the above code I get

"HEX KEY: 6931375a4a656b635566334a2f502f45466b33666d58485342 6e78664d7666364246754e306b62493537513d, ORIG KEY: i17ZJekcUf3J/P/EFk3fmXHSBnxfMvf6BFuN0kbI57Q="

"HEX IV: 776d556c57452b456d554d6775472f65616c6f4d63673d3d, ORIG IV: wmUlWE+EmUMguG/ealoMcg=="

FAILED "AESKey" AESKey 57616 "SB_ERR_BAD_KEY_LEN (57616)"

"Could not create a key. SB_ERR_BAD_KEY_LEN (57616)"

Cipher text is not valid hex
"ENCRYPTED , DECRYPTED: "


Thanks so much! Hope someone can help.

[wysota]

Where is that 'crypt' method implemented? Have you verified that it works properly?