How to use AES-256 encryption in lockbox 3 using delphi

Question

I've downloaded Lockbox3 about a week ago and i can't use it, and i couldn't understand the demo because it's complex i couldn't get the codes i want from it, I'd like to use lockbox 3 AES-256 encryption to encrypt strings in Delphi.

What are you trying to do, specifically? What have tried to make this work? What error message(s) did you receive? You are unlikely to get votes or a focused answer if you don't ask a very clear, focused question. You might want to read the faq linked above. — Argalatyr, Feb 26 '12 at 01:44

score 5 · Accepted Answer · answered Feb 26 '12 at 13:43

The method and property names pretty much say it all. Here is a method which encrypts a string and then decrypts it back again, assuming you've setup the codec properties at design time, which are also self-describing.

procedure TForm1.actEncryptStringExecute( Sender: TObject );
var
  Plaintext, sReconstructedPlaintext: string;
  base64Ciphertext: ansistring;
begin
sPlainText := 'I love LockBox 3!';
if not InputQuery( 'Plaintext', 'Enter plaintext that you want to encrypt (UTF-16LE encoding):', sPlainText) then exit;
codec.EncryptString( sPlaintext, base64Ciphertext);
ShowMessageFmt('The base64 encoding of the encoded ciphertext is'#13#10+'%s',[base64Ciphertext]);
codec.DecryptString( sReconstructedPlaintext, base64Ciphertext);
ShowMessageFmt('After decryption, this decrypts back to %s',[sReconstructedPlaintext])
end;

Have another look at the demo program. The handler for Encrypt button, encrypts a file instead of a string. That aside, if you strip away the decorative fluff, like posting information to a memo, and handling exceptions if the user specified a non-existant file, its increddibly simple - it basically boils down to one line...

codecMainDemo.EncryptFile( edtPlaintextFile.Text, edtCiphertextFile.Text );

To encrypt a string, you call EncryptString(). To encrypt a file you call EncryptFile().

The demo shows the setup, to wit:

Put an TCryptographicLibrary component on your form;
Put a TCodec component on your form;
Select your prefered cipher
Select your prefered chaining mode; and
Set the password

and Bob's your uncle!

Let me know if you have any problems.

I have just install these components into XE6, EncryptString needs as third parameter some TEncoding from Sysutils, what shall I do with that? — Vlastimil Burián, Sep 18 '16 at 19:45
It depends on what string encoding do you want. UTF-8? UTF-16LE? or something else. — Sean B. Durkin, Sep 19 '16 at 07:01
normal ASCII string, I have no idea on what to do with it, thank you beforehand — Vlastimil Burián, Sep 19 '16 at 07:22
What is a "normal ASCII string"? Maybe you mean UTF-8? - then use TEncoding.UTF8 . — Sean B. Durkin, Sep 19 '16 at 07:25

score -1 · Answer 2 · edited Feb 22 '21 at 21:55

Sean Your example has at least one error if not more:

var
  Plaintext, sReconstructedPlaintext: string;
  base64Ciphertext: ansistring;
Plaintext should be sPLaintext.

Plus Delphi Sydney compiler flags an error 'Not enough actual parameters' on codec.EncryptString( sPlaintext, base64Ciphertext);

I think that uncle bob was having an off day. This is a great library but unfortunately it is let down by poor documentation. I have ploughed my way through the relevant units in order to make some progress but it is a shame that I have to do this in order to assess whether I want to use it - I am writing a textbook for the school's market.

How to use AES-256 encryption in lockbox 3 using delphi

2 Answers2

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