[Haskell-cafe] How to use an crypto with hackage cereal?

[Magicloud Magiclouds]

Similar as you envisaged. I would receive a bytestring data and a config
point out what cipher to use. Then I deserialize the data to a data type
with some fields. The serialize process is something like:

msum $ map (encrypt . encode) [field1, field2, field3]

I could parse the bytestring outside Get/Put monads. But I think that looks
ugly. I really want to embed the decrypt process into Get/Put monads.

On Tue, Apr 21, 2015 at 10:08 PM, Ivan Lazar Miljenovic <
ivan.miljenovic at gmail.com> wrote:

> On 21 April 2015 at 23:58, Magicloud Magiclouds
> <magicloud.magiclouds at gmail.com> wrote:
> > Thank you. But how if the cipher was specified outside the binary data? I
> > mean I need to pass the decrypt/encrypt function to get/put while they do
> > not accept parameters. Should I use Reader here?
>
> Maybe you could explain what you're doing better.
>
> I would envisage that you would get a Bytestring/Text value, then
> encrypt/decrypt and then put it back (though if you're dealing with
> Bytestrings, unless you're wanting to compose them with others there's
> no real need to use Get and Put as you'll have the resulting
> Bytestring already...).
>
> Or are you wanting to implement your own encryption/decryption scheme?
>  In which case, you might want to either:
>
> a) write custom functions in the Get and Put monads OR
>
> b) write custom parsers (e.g. attoparsec) and builders (using the
> Builder module in bytestring); this is probably going to suit you
> better.
>
> >
> > On Tue, Apr 21, 2015 at 6:43 PM, Yitzchak Gale <gale at sefer.org> wrote:
> >>
> >> Magicloud Magiclouds wrote:
> >> > I am trying to work with some binary data that encrypted by field
> >> > instead of
> >> > the result of serialization. I'd like to use Data.Serialize to wrap
> the
> >> > data
> >> > structure. But I could not figure out how to apply an runtime
> specified
> >> > cipher method to the bytestring.
> >>
> >> Are you using the set of crypto libraries written by
> >> Victor Hanquez, such as cryptocipher-types,
> >> crypto-pubkey-types, and cryptohash?
> >>
> >> Or the set of libraries written by Thomas DuBuisson,
> >> such as crypto-api, cipher-aes128, etc.?
> >>
> >> Here is an example of decoding for Victor's libraries.
> >> Encoding would be similar using Put instead of Get.
> >> Thomas' libraries would be similar using the other
> >> API.
> >>
> >> Let's say you have a type like this:
> >>
> >> data MyCipher = MyAES | MyBlowfish | ...
> >>
> >> Then in your cereal code you would have a Get monad
> >> expression something like this (assuming you have
> >> written all of the functions called parseSomething):
> >>
> >> getStuff = do
> >>   cipher <- parseCipher :: Get MyCipher
> >>   clearText <- case cipher of
> >>     MyAES -> do
> >>       keyBS <- parseAESKey :: Get ByteString
> >>       let key = either (error "bad AES key") id $ makeKey keyBS
> >>           cipher = cipherInit key
> >>       cipherText <- parseAESCipherText :: Get ByteString
> >>       return $ ecbDecrypt cipher cipherText
> >>     MyBlowfish -> do ...
> >>
> >> etc.
> >>
> >> Hope this helps,
> >> Yitz
> >
> >
> >
> >
> > --
> > 竹密岂妨流水过
> > 山高哪阻野云飞
> >
> > And for G+, please use magiclouds#gmail.com.
> >
> > _______________________________________________
> > Haskell-Cafe mailing list
> > Haskell-Cafe at haskell.org
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> >
>
>
>
> --
> Ivan Lazar Miljenovic
> Ivan.Miljenovic at gmail.com
> http://IvanMiljenovic.wordpress.com
>



-- 
竹密岂妨流水过
山高哪阻野云飞

And for G+, please use magiclouds#gmail.com.
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