Blowfish - on a string

[Lindon]

@Christoph-Hart said in Blowfish - on a string:

If you think this is your line of defense

The pirate cannot generate new serials because they dont have the private key,

then this is the attack vector:

and check against the array of serials (that is clearly viewable by the pirate) inside the plugin.

A keygen would simply contain the "clearly viewable" list of valid serials and spit out one of them:

inline function nastyKeygen()
{
     return extractedKeygens[Math.randInt(0, extractedKeygens.length);
}

If you want to up your copy protection game, just use the ScriptLocker class. This enforces a system identification and a server call, but if your server is hacked, then you might as well give up.

well I think one of us doesn't understand RSA = it could well be me....

Heres a serial: 1234-1234

I take the encrypting(private) key and generate an encrypted version....

qw247dnwpoie75hb4985345h34

I give this to my customer....

My app asks for this encrypted key:...

The app contains the decrypting(public) key:

333eee333eerr444rrr

it uses this public key to decrypt it the serial provided by the user, getting:

1234-1234

it checks against the array of valid serials held in the app:

1234-1234
5668-5678
2345-6784
2291-6144

its present so valid all good....

Along comes my pirate, he gets a copy of my app:

he can see the list of serials...

1234-1234
5668-5678
2345-6784
2291-6144

he can see the public key:

333eee333eerr444rrr

Okay so now he needs to generate an encrypted serial that will be decrypted by the public key....for that he needs the private key....he doesn't have it..and its very complex to get it. So he will have to hack the code.

Did I misunderstand something?

[Lindon]

@Lindon so I think what I'm looking for is these JUCE calls to be implemented in HISE

static void RSAKey::createKeyPair(
RSAKey & publicKey,
RSAKey & privateKey,
int 	numBits,
const int * 	randomSeeds = nullptr,
int 	numRandomSeeds = 0 
)	

which is a convenience but gives me two RSA keys...

and this:

bool RSAKey::applyToValue(BigInteger & value)const

which I can use with the encoding key to encode my serials, and with the decoding key to decode them...

[Christoph Hart]

@Lindon Actually, no, you're right. I forgot the decryption step in my calculations...

Alright, you win. But I would recommend to not store serials inside the plugin (unnecessary loading time for parsing ten of thousands of JSON strings, possibility of license overflow), but to just check them with any arbitrary logic:

isSerialValid(decryptedSerial)
{
    return decryptedSerial.charAt(4) = 'A'; // or something a bit more secure...
}

then only generate serials that match against that filter in your keygen.

[Lindon]

@Christoph-Hart said in Blowfish - on a string:

@Lindon Actually, no, you're right. I forgot the decryption step in my calculations...

Alright, you win. But I would recommend to not store serials inside the plugin (unnecessary loading time for parsing ten of thousands of JSON strings, possibility of license overflow), but to just check them with any arbitrary logic:

isSerialValid(decryptedSerial)
{
    return decryptedSerial.charAt(4) = 'A'; // or something a bit more secure...
}

then only generate serials that match against that filter in your keygen.

hmm, yeah that looks good... - still I'd like to be in the position to require "tens of thousands" of strings....LOL.

The actual next thing to do is to recreate the decrypt-and-check-steps in several places in the plug-in AND to do so in slightly different ways each time so the result isnt easy to just pattern match trace in the script...the to defer some of them, time and functionality based...

[Christoph Hart]

Alright, it's pushed (won't show up in the API until I'm back on my Windows system though). You can create the RSA key pairs already in the Tools menu. Just make sure you don't save it as file, or HISE will think you are using its copy protection...

// You can create those with "Tools / Create RSA Key pair, then copy to clip board and paste it here"
const var publicKey =  "101,6e72f1e9720ba9f28c32034c61575948f919ec78d97ad0cecd539f798084e284d983c580db1d3fb72897535305df0bc61769825f18174a46c2d524b32138f80d";

// Obviously don't include that one in your shipped product...
const var privateKey =  "c0889eb9cdc6a2c5afa7dde7c29645f9ba332aa8d3c32a3fa7aaac6838afdc89a1b66da08b40f71c68797a4977b00c3c3a8dcf750adc9238b1c0a42c78a4b01,6e72f1e9720ba9f28c32034c61575948f919ec78d97ad0cecd539f798084e284d983c580db1d3fb72897535305df0bc61769825f18174a46c2d524b32138f80d";

const var dummyData = "1234abc"

const var encrypted = FileSystem.encryptWithRSA(dummyData, privateKey);

const var decrypted = FileSystem.decryptWithRSA(encrypted, publicKey);

Console.print(encrypted);
Console.print(decrypted);

[Lindon]

@Christoph-Hart man you're quick...Thanks.

[Dan Korneff]

@Lindon Did you get this implemented yet?

[Christoph Hart]

@dustbro Paste the code into a script and find out :)

[Dan Korneff]

@Christoph-Hart I have no doubt that it works. I guess that was just opening a conversation to "how does it work?" Is there a flow chart or something I can look at? I have a key that I'd like to hide in my script, and this seems like a way to do it... I just don't know how it works. .

[Lindon]

@dustbro depends what you mean by "hide" - read the "flow of control description" I wrote earlier...and it should be obvious.

RSA encryption/decryption allows you to hide one key, (the private key) and to use the public key(viewable) to decrypt the string

[Lindon]

@ustk said in Blowfish - on a string:

@Lindon I've just added two methods:
https://github.com/christophhart/HISE/pull/331

to use this way:

Did this ever get included in HISE? Its not working here...

[d.healey]

@Lindon Christoph posted an example a few posts up.

[Lindon]

@d-healey no, I'm looking for the simple blowfish stuff.... it doesnt seem to work anymore..

[d.healey]

@Lindon Looks like that pull request hasn't been merged yet.

[Lindon]

@d-healey -yeah I will use the write/read EncryptedObject then...

[d.healey]

@Lindon Or wait a few minutes for @Christoph-Hart to merge it hopefully :D

You could also pull it into your own fork.

[Lindon]

@d-healey said in Blowfish - on a string:

You could also pull it into your own fork.

Sometimes you make laugh out loud.....

[Christoph Hart]

@Lindon I've merged it.

[Lindon]

@Christoph-Hart -too late-I'm down the encryptedObject path now - :beaming_face_with_smiling_eyes: