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encrypt/decrypt seems spotty
Posted: Tue Sep 09, 2014 12:08 am
by Da_Elf
Was trying a demo stack i found online which lets you encrypt or decrypt information via two simple functions. I replicated those functions and setup an example using blowfish as the encryption method. All i wanted was some data thats encrypted to be stored to a file and new data added to it. So i get some data... a name... then i encrypt it and save to a file. Then i read from the file, decrypt the info, add a new name on a new line then re-encrypt the info and stick it back into the file. Most of that works ok. but i got it to answer out some of the stuff like the decrypted info and the new info to be encrypted and unfortunately it seems like its not decrypting stuff properly. Sometimes the info is messed up. sometimes its just blank. its weird
Re: encrypt/decrypt seems spotty
Posted: Tue Sep 09, 2014 12:21 am
by sefrojones
On which platform/ Version of LC are you experiencing this?
Re: encrypt/decrypt seems spotty
Posted: Tue Sep 09, 2014 1:25 am
by Da_Elf
LC 6.6.2 on windows 7
These are the functions
Code: Select all
function fCipher vText PassCode
encrypt vText using "blowfish" with PassCode at 128 bit
return it
end fCipher
function fDecipher vText PassCode
decrypt vText using "blowfish" with PassCode at 128 bit
return it
end fDecipher
Ive got a simple text input field called "Text" and a simple button with this code on the button
Code: Select all
on mouseUp
put URL "file:code.code" into rText
put text of field "Text" into addText
if rText <> empty then
put fDecipher(rText,"Pass") into decodedText
put decodedText & return & addText into newText
else
put addText into newText
end if
answer "To be encoded"&return&"----------------------"&return&newText
put fCipher(newText,"Pass") into encodedText
put encodedText into URL "file:code.code"
end mouseUp
by the 7th or 8th entry it starts to mess up
Re: encrypt/decrypt seems spotty
Posted: Tue Sep 09, 2014 2:35 am
by sefrojones
I can confirm this behavior in LC 7.0 RC1 back to 6.5.2 GM running in Ubuntu 14.04 64 bit, beyond that IDK. possible bug?
Re: encrypt/decrypt seems spotty
Posted: Tue Sep 09, 2014 3:49 am
by Da_Elf
the behavior is confirmed but is it due to an error on my part or is my code ok?
Re: encrypt/decrypt seems spotty
Posted: Tue Sep 09, 2014 3:56 am
by Da_Elf
actually. on a random thought i figured that maybe the decoder or encoder couldnt do its magic fast enough to keep up with the rest of livecodes functions and it gets confused. so i added a wait command of 2 seconds after decoding and after encoding and ive just entered 14 lines so far with no mistakes... spoke too soon. at 15 i decided to use some long strings and around 17 it started giving problems again.
its like it needs time to encode and decode and the more info there is to encode and decode the longer it takes
Re: encrypt/decrypt seems spotty
Posted: Tue Sep 09, 2014 5:32 am
by Simon
it's "binfile:"
Simon
Re: encrypt/decrypt seems spotty
Posted: Tue Sep 09, 2014 5:34 am
by FourthWorld
Use the binary specifier ("binfile" when using URL syntax) when reading/writing files containing binary data, e.g.:
put tSomeData into url ("binfile: "& tSomePath)
Re: encrypt/decrypt seems spotty
Posted: Tue Sep 09, 2014 5:55 am
by sefrojones
And that solves that. Thanks Simon and Richard.
Re: encrypt/decrypt seems spotty
Posted: Tue Sep 09, 2014 11:27 am
by Da_Elf
thanks. i didnt think of binfile since i always imagined binary data to be ones and zeros. not the weird stuff i see in the blowfish encrypted file
Re: encrypt/decrypt seems spotty
Posted: Tue Sep 09, 2014 2:58 pm
by FourthWorld
Da_Elf wrote:thanks. i didnt think of binfile since i always imagined binary data to be ones and zeros. not the weird stuff i see in the blowfish encrypted file
It's probably better to think of binary data as any wierd stuff that isn't easily readable.
The 1s and 0s of binary bits are treated by the computer in groups of 8 making a byte, and when displayed it'll use the character that corresponds with that byte value. In some cases this may seem somewhat readable, but interspersed with readable characters you'll also see things that look like junk.
As a general rule, anytime you see parts of text that look like junk, you're probably dealing with binary data. Specifying the binary options for reading and writing files will retain that data without alteration.
At this point you might be wondering, "If the binary option retains the data unaltered, what does the text option do and why is it the default?"
The reason for this is that much of what we do with computing involves human-readable text, and since LiveCode is a multi-platform tool it needs to account for the differences among the various OSes it supports, mostly with line-endings.
Windows uses two characters for line endings (ASCII 13 followed by ASCII 10), while Mac uses true ASCII return (ASCII 13), and Unix/Linux use ASCII 10.
It would be enormously cumbersome to work with text in LiveCode if all of our code had to check the current OS and parse text in different ways for different OSes.
So instead, within LiveCode a return always uses the Unix convention of ASCII 10 (much as it uses the Unix convention for path delimiters, regardless of platform).
And to make this happen, when it reads text files from disk it translates line endings to use ASCII 10, which is what we want when working with plain text, but as you can imagine this can wreak havoc with binary files where it's important to retain every value as-is.
So the default mode is text to make it easy to work with simple text files across platforms, and when you need to work with binary data you can specify that that's what you're doing and it'll bypass the line-ending translation.
Re: encrypt/decrypt seems spotty
Posted: Tue Sep 09, 2014 9:08 pm
by Da_Elf
thanks richard. thats most helpful