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Delphi ActiveX

Set JWE Additional Authenticated Data

See more JSON Web Encryption (JWE) Examples

Demonstrates Jwe.SetAad, which sets external Additional Authenticated Data (AAD) for a JWE being encrypted, encoding the supplied text with the given charset.

Background. AAD is integrity-protected but not encrypted, binding external context to the ciphertext. The same AAD must be supplied again when decrypting.

Chilkat Delphi ActiveX Downloads

Delphi ActiveX
var
success: Integer;
jwe: TChilkatJwe;
header: TChilkatJsonObject;
base64Key: WideString;
sbContent: TChilkatStringBuilder;
sbJwe: TChilkatStringBuilder;

begin
success := 0;

jwe := TChilkatJwe.Create(Self);

//  Protected header: AES key-wrap with AES-256-GCM content encryption.
header := TChilkatJsonObject.Create(Self);
header.UpdateString('alg','A256KW');
header.UpdateString('enc','A256GCM');
success := jwe.SetProtectedHeader(header.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(jwe.LastErrorText);
    Exit;
  end;

//  The 256-bit key-wrapping key (base64) for recipient index 0.  In production, obtain the key from a
//  secure source rather than hard-coding it.
base64Key := 'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=';
success := jwe.SetWrappingKey(0,base64Key,'base64');
if (success = 0) then
  begin
    Memo1.Lines.Add(jwe.LastErrorText);
    Exit;
  end;

//  Set external Additional Authenticated Data (AAD).  The AAD is integrity-protected but not
//  encrypted, and must be supplied again when decrypting.
success := jwe.SetAad('context-info-v1','utf-8');
if (success = 0) then
  begin
    Memo1.Lines.Add(jwe.LastErrorText);
    Exit;
  end;

sbContent := TChilkatStringBuilder.Create(Self);
sbContent.Append('This is the secret content.');
sbJwe := TChilkatStringBuilder.Create(Self);
success := jwe.EncryptSb(sbContent.ControlInterface,'utf-8',sbJwe.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(jwe.LastErrorText);
    Exit;
  end;
Memo1.Lines.Add(sbJwe.GetAsString());