Pascal (Lazarus/Delphi)

Set the OAEP Hash Algorithm for Encrypted Email

Demonstrates the Chilkat Email.OaepHash property, which selects the hash algorithm used by OAEP padding when encrypting email with RSAES-OAEP. Valid values are sha1, sha256, sha384, and sha512; the default is sha256. This property is used only when OaepPadding is true, so this example enables OAEP first.

Background: OAEP ("Optimal Asymmetric Encryption Padding") uses a hash function internally as part of the randomized padding it wraps around the data before RSA encryption. The choice of hash affects security and, importantly, interoperability: the sender and recipient must use the same OAEP hash, or decryption fails. That is why this is exposed as an explicit setting rather than left implicit.

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Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Email;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  email: TEmail;

begin
  //  Demonstrates the Email.OaepHash property, which selects the hash algorithm used by
  //  OAEP padding when encrypting email with RSAES-OAEP.  Valid values: sha1, sha256,
  //  sha384, sha512.  The default is sha256.  It is used only when OaepPadding is true.

  email := TEmail.Create;
  email.Subject := 'Encrypted with RSAES-OAEP';

  //  OAEP padding must be enabled for the OAEP hash to take effect.
  email.OaepPadding := True;
  email.OaepHash := 'sha256';

  WriteLn('OaepHash = ' + email.OaepHash);


  email.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.