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Delphi DLL

Set JWE Additional Authenticated Data from BinData

See more JSON Web Encryption (JWE) Examples

Demonstrates Jwe.SetAadBd, which sets external Additional Authenticated Data (AAD) to the exact bytes held in a BinData.

Background. AAD is integrity-protected but not encrypted. Passing an empty BinData clears any previously configured AAD.

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Delphi DLL
var
success: Boolean;
jwe: HCkJwe;
header: HCkJsonObject;
base64Key: PWideChar;
bdAad: HCkBinData;
sbContent: HCkStringBuilder;
sbJwe: HCkStringBuilder;

begin
success := False;

jwe := CkJwe_Create();

//  Protected header: AES key-wrap with AES-256-GCM content encryption.
header := CkJsonObject_Create();
CkJsonObject_UpdateString(header,'alg','A256KW');
CkJsonObject_UpdateString(header,'enc','A256GCM');
success := CkJwe_SetProtectedHeader(jwe,header);
if (success = False) then
  begin
    Memo1.Lines.Add(CkJwe__lastErrorText(jwe));
    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 := CkJwe_SetWrappingKey(jwe,0,base64Key,'base64');
if (success = False) then
  begin
    Memo1.Lines.Add(CkJwe__lastErrorText(jwe));
    Exit;
  end;

//  Set external Additional Authenticated Data (AAD) to the exact bytes in a BinData.  Passing an empty
//  BinData clears any previously configured AAD.
bdAad := CkBinData_Create();
CkBinData_AppendString(bdAad,'context-info-v1','utf-8');
success := CkJwe_SetAadBd(jwe,bdAad);
if (success = False) then
  begin
    Memo1.Lines.Add(CkJwe__lastErrorText(jwe));
    Exit;
  end;

sbContent := CkStringBuilder_Create();
CkStringBuilder_Append(sbContent,'This is the secret content.');
sbJwe := CkStringBuilder_Create();
success := CkJwe_EncryptSb(jwe,sbContent,'utf-8',sbJwe);
if (success = False) then
  begin
    Memo1.Lines.Add(CkJwe__lastErrorText(jwe));
    Exit;
  end;
Memo1.Lines.Add(CkStringBuilder__getAsString(sbJwe));

CkJwe_Dispose(jwe);
CkJsonObject_Dispose(header);
CkBinData_Dispose(bdAad);
CkStringBuilder_Dispose(sbContent);
CkStringBuilder_Dispose(sbJwe);