(Delphi DLL) RSAES-OAEP Encrypt String with AES-128 Content Encryption and SHA256

Encrypts a string using RSAES-OAEP with SHA256 and AES-128 content encryption to produce PKCS7 output (base64 encoded).

Note: This example requires Chilkat v9.5.0.67 or greater.

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, StringBuilder, Cert, Crypt2;

...

procedure TForm1.Button1Click(Sender: TObject);
var
sb: HCkStringBuilder;
i: Integer;
cert: HCkCert;
success: Boolean;
crypt: HCkCrypt2;
base64Pkcs7: PWideChar;

begin
// This example requires the Chilkat Crypt API to have been previously unlocked.
// See Unlock Chilkat Crypt for sample code.

// First build a string to be encrypted
sb := CkStringBuilder_Create();
i := 1;
while i < 25 do
  begin
    CkStringBuilder_AppendInt(sb,i);
    CkStringBuilder_Append(sb,' the quick brown fox jumped over the lazy dog.' + #13#10);
    i := i + 1;
  end;

Memo1.Lines.Add(CkStringBuilder__getAsString(sb));

// The string to be encrypted looks like this:

// 1 the quick brown fox jumped over the lazy dog.
// 2 the quick brown fox jumped over the lazy dog.
// 3 the quick brown fox jumped over the lazy dog.
// 4 the quick brown fox jumped over the lazy dog.
// 5 the quick brown fox jumped over the lazy dog.
// 6 the quick brown fox jumped over the lazy dog.
// ...

// Load a digital certificate. 
// We don't need the private key for encryption.
// Only the public key is needed (which is included in a certificate).
cert := CkCert_Create();
success := CkCert_LoadFromFile(cert,'qa_data/rsaes-oaep/cert.pem');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkCert__lastErrorText(cert));
    Exit;
  end;

crypt := CkCrypt2_Create();

// Tell the crypt object to use the certificate.
CkCrypt2_SetEncryptCert(crypt,cert);

// Indicate that we want PKI encryption (i.e. public-key infrastructure)
// to produce a CMS message (Cryptographic Message Syntax/PKCS7),
// that is be created with RSAES-OAEP padding, SHA256, and AES-128 for the
// bulk encryption.
CkCrypt2_putCryptAlgorithm(crypt,'pki');
CkCrypt2_putPkcs7CryptAlg(crypt,'aes');
CkCrypt2_putKeyLength(crypt,128);
CkCrypt2_putOaepHash(crypt,'sha256');
CkCrypt2_putOaepPadding(crypt,True);

// Also, don't forget to be specific about the character encoding (byte representation) of the
// string to be encrypted.
CkCrypt2_putCharset(crypt,'utf-8');

// Now indicate that the PKCS7 output is to be returned in the base64 encoding.
CkCrypt2_putEncodingMode(crypt,'base64');

base64Pkcs7 := CkCrypt2__encryptStringENC(crypt,CkStringBuilder__getAsString(sb));
if (CkCrypt2_getLastMethodSuccess(crypt) <> True) then
  begin
    Memo1.Lines.Add(CkCrypt2__lastErrorText(crypt));
    Exit;
  end;

// Show the output
Memo1.Lines.Add(base64Pkcs7);

// This base64 can be copy-and-pasted into the form at http://lapo.it/asn1js/
// to verify that all the chosen algorithms were indeed used.

Memo1.Lines.Add('OK.');

CkStringBuilder_Dispose(sb);
CkCert_Dispose(cert);
CkCrypt2_Dispose(crypt);

end;