MemoryReadStream *blowfishEBC(SeekableReadStream &input, const std::vector<byte> &key, Mode mode) {
BlowfishContext ctx;
blowfishSetKey(ctx, &key[0], key.size());
size_t inputSize = input.size() - input.pos();
// Round up to the next multiple of the block size
const size_t outputSize = ((inputSize + kBlockSize - 1) / kBlockSize) * kBlockSize;
ScopedArray<byte> output(new byte[outputSize]);
byte buffer[kBlockSize];
byte *data = output.get();
while (inputSize > 0) {
const size_t toRead = MIN<size_t>(inputSize, kBlockSize);
if (input.read(buffer, toRead) != toRead)
throw Exception(kReadError);
std::memset(buffer + toRead, 0, kBlockSize - toRead);
blowfishECB(ctx, mode, buffer, data);
data += toRead;
inputSize -= toRead;
}
return new MemoryReadStream(output.release(), outputSize, true);
}
bool Cipher::encrypt(QByteArray& cipherText)
{
if (cipherText.left(3) == "+p ") // don't encode if...?
cipherText = cipherText.mid(3);
else {
if (m_cbc) // encode in ecb or cbc decide how to determine later
{
QByteArray temp = blowfishCBC(cipherText, true);
if (temp == cipherText) {
// kDebug("CBC Encoding Failed");
return false;
}
cipherText = "+OK *" + temp;
}
else {
QByteArray temp = blowfishECB(cipherText, true);
if (temp == cipherText) {
// kDebug("ECB Encoding Failed");
return false;
}
cipherText = "+OK " + temp;
}
}
return true;
}
QByteArray Cipher::decryptTopic(QByteArray cipherText)
{
if (cipherText.mid(0, 4) == "+OK ") // FiSH style topic
cipherText = cipherText.mid(4);
else if (cipherText.left(5) == "«m«")
cipherText = cipherText.mid(5, cipherText.length() - 10);
else
return cipherText;
QByteArray temp;
// TODO currently no backwards sanity checks for topic, it seems to use different standards
// if somebody figures them out they can enable it and add "ERROR_NONECB/CBC" warnings
if (m_cbc)
temp = blowfishCBC(cipherText.mid(1), false);
else
temp = blowfishECB(cipherText, false);
if (temp == cipherText) {
return cipherText;
}
else
cipherText = temp;
if (cipherText.mid(0, 2) == "@@")
cipherText = cipherText.mid(2);
return cipherText;
}
QByteArray Cipher::decrypt(QByteArray cipherText)
{
QByteArray pfx = "";
bool error = false; // used to flag non cbc, seems like good practice not to parse w/o regard for set encryption type
// if we get cbc
if (cipherText.mid(0, 5) == "+OK *") {
// if we have cbc
if (m_cbc)
cipherText = cipherText.mid(5);
// if we don't
else {
cipherText = cipherText.mid(5);
pfx = "ERROR_NONECB: ";
error = true;
}
}
// if we get ecb
else if (cipherText.mid(0, 4) == "+OK " || cipherText.mid(0, 5) == "mcps ") {
// if we had cbc
if (m_cbc) {
cipherText = (cipherText.mid(0, 4) == "+OK ") ? cipherText.mid(4) : cipherText.mid(5);
pfx = "ERROR_NONCBC: ";
error = true;
}
// if we don't
else {
if (cipherText.mid(0, 4) == "+OK ")
cipherText = cipherText.mid(4);
else
cipherText = cipherText.mid(5);
}
}
// all other cases we fail
else
return cipherText;
QByteArray temp;
// (if cbc and no error we parse cbc) || (if ecb and error we parse cbc)
if ((m_cbc && !error) || (!m_cbc && error)) {
temp = blowfishCBC(cipherText, false);
if (temp == cipherText) {
// kDebug("Decryption from CBC Failed");
return cipherText + ' ' + '\n';
}
else
cipherText = temp;
}
else {
temp = blowfishECB(cipherText, false);
if (temp == cipherText) {
// kDebug("Decryption from ECB Failed");
return cipherText + ' ' + '\n';
}
else
cipherText = temp;
}
// TODO FIXME the proper fix for this is to show encryption differently e.g. [nick] instead of <nick>
// don't hate me for the mircryption reference there.
if (cipherText.at(0) == 1)
pfx = "\x0";
cipherText = pfx + cipherText + ' ' + '\n'; // FIXME(??) why is there an added space here?
return cipherText;
}
