SHA-256 calculation

[d3n1s]

Hi!
Please tell how to calculate SHA-256 of String like '0AF3D2E1' in free pascal.
I need a simple way to use any 'function(S: String): String'

[Bart]

DCPcrypt?

Bart

[d3n1s]

I try to calculate SHA-256 with DCPCrypt, but I don't understand how to do it in a simple way.
Please tell me if you know how to use DCPCrypt

[Zoran]

Please tell me if you know how to use DCPCrypt

A bit more information here: https://is.muni.cz/th/51468/fi_b/priloha/DCPcrypt/Docs/Index.html

[Ericktux]

Greetings my friends, this is my contribution 
Get SHA256 of string.

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, FileUtil, DCPsha256, DCPripemd160, Forms, Controls,
9.   Graphics, Dialogs, StdCtrls;
10.  
11. type
12.  
13.   { TForm1 }
14.  
15.   TForm1 = class(TForm)
16.     Button1: TButton;
17.     DCP_sha256_1: TDCP_sha256;
18.     Edit1: TEdit;
19.     Edit2: TEdit;
20.     Label1: TLabel;
21.     procedure Button1Click(Sender: TObject);
22.   private
23.     { private declarations }
24.   public
25.  
26.     { public declarations }
27.   end;
28.  
29. var
30.   Form1: TForm1;
31.  
32. implementation
33.  
34. {$R *.lfm}
35.  
36. { TForm1 }
37.  
38. function getsha256(S: String): String;
39. var
40.     Hash: TDCP_sha256;
41.     Digest: array[0..31] of byte;  // sha256 produces a 256bit digest (32bytes)
42.     Source: string;
43.     i: integer;
44.     str1: string;
45.   begin
46.     Source:= S;  // here your string for get sha256
47.  
48.     if Source <> '' then
49.     begin
50.       Hash:= TDCP_sha256.Create(nil);  // create the hash
51.       Hash.Init;                        // initialize it
52.       Hash.UpdateStr(Source);
53.       Hash.Final(Digest);               // produce the digest
54.       str1:= '';
55.       for i:= 0 to 31 do
56.         str1:= str1 + IntToHex(Digest[i],2);
57.       //form1.Edit2.Text:= s;                   // display the digest in lower case
58.       form1.Edit2.Text:=UpperCase(str1);         // display the digest in capital letter
59.  
60.     end;
61.   end;
62.  
63. procedure TForm1.Button1Click(Sender: TObject);
64. begin
65.      getsha256(Edit1.Text);  // show the sha256 of string in edit1
66. end;
67.  
68. end.

for now work fine 
PD: Attached image and example

[Ericktux]

For SHA256 of files you can try this example 

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, FileUtil, DCPsha256, DCPripemd160, Forms, Controls,
9.   Graphics, Dialogs, StdCtrls;
10.  
11. type
12.  
13.   { TForm1 }
14.  
15.   TForm1 = class(TForm)
16.     Button1: TButton;
17.     Button2: TButton;
18.     DCP_sha256_1: TDCP_sha256;
19.     Edit1: TEdit;
20.     Edit2: TEdit;
21.     Label1: TLabel;
22.     OpenDialog1: TOpenDialog;
23.     procedure Button1Click(Sender: TObject);
24.     procedure Button2Click(Sender: TObject);
25.   private
26.     { private declarations }
27.   public
28.  
29.     { public declarations }
30.   end;
31.  
32. var
33.   Form1: TForm1;
34.  
35. implementation
36.  
37. {$R *.lfm}
38.  
39. { TForm1 }
40.  
41. function getsha256_file(S: String): String;   // "S" is path of file
42. var
43.     Hash: TDCP_sha256;
44.     Digest: array[0..31] of byte;  // sha256 produces a 256bit digest (32bytes)
45.     Source: TFileStream;
46.     i: integer;
47.     str1: string;
48.   begin
49.     Source:= nil;
50.     try
51.       Source:= TFileStream.Create(s,fmOpenRead);  // open the file specified by Edit1
52.     except
53.       MessageDlg('Unable to open file',mtError,[mbOK],0);
54.     end;
55.  
56.     if Source <> nil then
57.     begin
58.       Hash:= TDCP_sha256.Create(nil);  // create the hash
59.       Hash.Init;                        // initialize it
60.       Hash.UpdateStream(Source, Source.Size);
61.       Hash.Final(Digest);               // produce the digest
62.       Source.Free;
63.       str1:= '';
64.       for i:= 0 to 31 do
65.         str1:= str1 + IntToHex(Digest[i],2);
66.       //form1.Edit2.Text:= s;                   // display the digest in lower case
67.       form1.Edit2.Text:=UpperCase(str1);         // display the digest in capital letter
68.  
69.     end;
70.   end;
71.  
72. procedure TForm1.Button1Click(Sender: TObject);
73. begin
74.      getsha256_file(Edit1.Text);  // show the sha256 of file in edit1
75. end;
76.  
77. procedure TForm1.Button2Click(Sender: TObject);
78. begin
79.     if OpenDialog1.Execute then
80.     begin
81.     Edit1.Text:=OpenDialog1.Filename;
82.     end;
83. end;
84.  
85. end.

Regards

[d3n1s]

Thank you!!! It's working!

[Gizmo]

I've a lot of experience using DCPCrypt, and it is very good. But it's worth noting I recently migrated my data hashing project to HasLib4Pascal (https://github.com/Xor-el/HashLib4Pascal), which is preferable for my needs.

To compute for a string, it is as simple as :

 result := THashFactory.TCrypto.CreateSHA2_256().ComputeString(strToBeHashed, TEncoding.UTF8).ToString();
(https://github.com/tedsmith/quickhash/blob/master/unit2.pas#L2223)

[ASBzone]

I also appreciate the HashLib4Pascal library -- it is very effective.

-ASB