[Haskell-cafe] Haskell, crypto and OpenSSL

[Donald Bruce Stewart]

dons:
>     -- Fast md5 using OpenSSL and non-copying bytestrings
>     md5sum :: B.ByteString -> String
>     md5sum p = unsafePerformIO $ B.unsafeUseAsCStringLen p $ \(ptr,n) -> do
>         digest  <- c_md5 ptr (fromIntegral n) nullPtr
>         liftM concat $ forM [0..15] $ \n -> do
>                             w <- peekElemOff digest n
>                             return $ case showHex w [] of [x] -> ['0', x]; x -> x
> 
>     -- unsigned char *MD5(const unsigned char *d, unsigned long n, unsigned char *md);
>     foreign import ccall "openssl/md5.h MD5" c_md5
>         :: Ptr CChar -> CULong -> Ptr CChar -> IO (Ptr Word8)
> 
> ByteStrings were designed for this zero-copy passing of big data to C,
> by the way, so its a perfect fit.

by the way, I note we do have a binding to OpenSSL, of sorts:

    http://cryp.to/hopenssl/

But it needs updating to use ByteStrings. Would make a good project for
someone into crypto.

-- Don