python - os.urandom or ssl.RAND_bytes? -

-

os.urandom or ssl.rand_bytes: when generating random bytes cryptographic purposes, more recommended?

if neither 1 better, tradeoffs , expected each in terms of differences?

note ssl.rand_bytes exists in python 3.

ssl.rand_bytes needs seeded before can used. cannot rely on ssl.rand_bytes alone. both os.urandom , `ssl.rand_bytes pseudo random number generators. prng's deterministic; when seeded same data, return same stream of pseudo random number bytes. these bytes should indistinguishable true random if observer not know seed value. os.urandom (re-)seeded using source of entropy within operating system.

using os.urandom should therefore preferred on ssl.rand_bytes. first of all, seeded (and reseeded operating system). furthermore, not require additional dependency on ssl library. drawback performance. faster use ssl.rand_bytes seeded big enough value os.urandom os.urandom requires system call time retrieve data.


Comments

Post a Comment

Popular posts from this blog

plot - Remove Objects from Legend When You Have Also Used Fit, Matlab -

-
Image
i've plotted data points , fitted exponential curve between them using 'fit' in matlab. problem fit-function got fitted line wanted plot, markers on top of regular markers. solved problem plotting wanted markers on top of unwanted couldn't seen. problem. when want show legends dots in there. how can remove markers legend without removing fitted line since both of them hidden inside fit-function? can stop 'fit' plotting unwanted markers? so, want remove blue dot called 'hoff' in picture below. you can leave out legend-entries manually leaving out handles of lines, dont want in legend. try this: %if plot something, want showing in legend, save handle: h_line = plot(x,y) %you dont want show line? dont anything, plot it: plot(mymarker) %then set legend-> can add text legend-entries %a cell-array containing strings want show up: legend([h_line another_line],{'text1' 'text2'}) with example (see comments) came solution:
Read more

java - Why does my date parsing return a weird date? -

-
here code using: string string = "08/07/2013".replace('/', '-'); date date = new simpledateformat("yyyy-mm-dd").parse(string); why date return: "wen jan 3 00:00:00 est 14"? not @ date format told use. edit: need format because database using requires format. the format use parse date string, not match it. using yyyy 08 . use following format: new simpledateformat("dd-mm-yyyy") and why @ replacing / - ? can build pattern original string only: string string = "08/07/2013" date date = new simpledateformat("dd/mm/yyyy").parse(string); and if want date string in yyyy-mm-dd format, can format date using dateformat#format(date) method: string formatteddate = new simpledateformat("yyyy-mm-dd").format(date); see also: change date format in java string simpledateformat java doc
Read more

Need help in packaging app using TideSDK on Windows -

-
i developed application using tidesdk on windows , when click launchapp works fine. moved package , installed imagemagick , wix 3.0 required packaging on windows. clicked on package runtime , cannot guess packaged app is? found file 'installer' in workspace when click on it says installer not find application path . think application not being packaged properly. here log see in tidesdk: preparing package desktop app runtime. 1 moment... staging trial -> copying contents d:\lab\tidesdk\trial d:\lab\tidesdk\trial\packages\win32\bundle\trial -> copying installer c:\programdata\tidesdk\sdk\win32\1.3.1-beta\installer d:\lab\tidesdk\trial\packages\win32\bundle\trial -> copying runtime d:\lab\tidesdk\trial\packages\win32\bundle\trial -> date: d:\lab\tidesdk\trial\packages\win32\bundle\trial\modules\app\1.3.1-beta -> date: d:\lab\tidesdk\trial\packages\win32\bundle\trial\modules\codec\1.3.1-beta -> date: d:\lab\tidesdk\trial\packages\win32\bundle\trial\mod
Read more