linq - Performance tuning C# permutations and SHA1 code -

-

although university assignment (homework) i've come best solution think of. achieve full marks code matches question, specially allowed develop in c# rather else using java, kind of "yeh, show c# can do" challenge ;-)

the question was:

create program find password of sha1 hash using brute force technique, assuming passwords 6 characters long , can contain lower-case a-z , 0-9.

i created linq query , after have possible combinations need run them through sha1 hash , compare provided password hash.

i created code:

public static string bruteforcehash(string hash)         {                  var results = c0 in enumerable.range(0, 36)                               c1 in enumerable.range(0, 36)                               c2 in enumerable.range(0, 36)                               c3 in enumerable.range(0, 36)                               c4 in enumerable.range(0, 36)                               c5 in enumerable.range(0, 36)                               select new string(                                   new[]                                 {                                     characters[c0],                                     characters[c1],                                     characters[c2],                                     characters[c3],                                     characters[c4],                                     characters[c5],                                 }                                   );                  string found = null;                 parallel.foreach(results, (result, loopstate, a) =>                                               {                                                   string hashed = sha1(result, encoding.default);                                                    if (hashed == hash)                                                   {                                                       found = result;                                                       loopstate.break();                                                   }                                               });                  if (found != null)                 {                     return found;                 }              return "not found.";         }

now real problem solved easy passwords ("aaaaaa" instant) takes longer further password away "aaaaaa".

i hope provide pointers on how increase performance.

if happy implementation run code performance profiler yourkit or dottrace can @ hot spot in code , @ tuning there. nice when using syntacticly sugared code linq, way can feel whats going on under hood too...


Comments

Post a Comment

Popular posts from this blog

python - Scipy curvefit RuntimeError:Optimal parameters not found: Number of calls to function has reached maxfev = 1000 -

-
Image
i want make logharitmic fit. keep getting runtime error: optimal parameters not found: number of calls function has reached maxfev = 1000 i use following script. can tell me go wrong? use spyder still beginner. import math import matplotlib mpl scipy.optimize import curve_fit import numpy np #data f1=[735.0,696.0,690.0,683.0,680.0,678.0,679.0,675.0,671.0,669.0,668.0,664.0,664.0] t1=[1,90000.0,178200.0,421200.0,505800.0,592200.0,768600.0,1036800.0,1371600.0,1630800.0,1715400.0,2345400.0,2409012.0] f1n=np.array(f1) t1n=np.array(t1) plt.plot(t1,f1,'ro',label="original data") # curvefit def func(t,a,b): return a+b*np.log(t) t=np.linspace(0,3600*24*28,13) popt, pcov = curve_fit(func, t, f1n, maxfev=1000) plt.plot(t, func(t, *popt), label="fitted curve") plt.legend(loc='upper left') plt.show() your original data t1 , f1 . therefore curve_fit should given t1 second argument, not t . popt, pcov = curve_fit(func,...
Read more

binding - How can you make the color of elements of a WPF DrawingImage dynamic? -

-
we have need make vector graphic images change color of elements within graphic @ runtime. seem setting colors based on either static or dynamic resource values wouldn't work. want have multiple versions of same graphic, each abilty set graphic elements (path, line, etc) different colors don't think dynamic resource approach work. leaves data binding seems right approach. update graphic use data binding expr instead of hard-coded brush color so: <drawingimage x:key="graphic1"> <drawingimage.drawing> <drawinggroup> <drawinggroup.children> <geometrydrawing geometry="f1 m 8.4073,23.9233l"> <geometrydrawing.pen> <pen linejoin="round" brush="{binding line1brush, mode=oneway}"/> </geometrydrawing.pen> </geometrydrawing> <geometrydrawing geometry="f1 m 3.6875,2.56251l"> <geometrydrawing....
Read more

c# - How to add a new treeview at the selected node? -

-
i have treeview 4 levels; parent, child, grandchild, great-grandchild. selectednode @ grandchild level. what i'm trying create new "treeview" @ grandchild - no, dont wnat create new node "selectednode" (grandchild). should somelike this: parent child grandchild (new treeview) parent grandchild great-grandchild child great-grandchild child grandchild grandchild it similar parent table mother , father went off , had new childern different spouse other spouse of there existing children. private sub populaterootlevel() ' query find first round of parent populatenodes(dt, jcatreeview.nodes) end sub private sub populatenodes(byval dt datatable, byval nodes treenodecollection) each dr datarow in dt.rows dim tn new treenode() tn.text = dr("title").tostring()...
Read more