From d3c8811fdb037dd7b67c60f88c19847e7a1d6a2d Mon Sep 17 00:00:00 2001
From: Benjamin Admin <benjaminadmin@MacBook-Pro.local>
Date: Mon, 4 May 2026 07:01:37 +0200
Subject: [PATCH] =?UTF-8?q?feat:=20IAB=20TCF=202.2=20=E2=80=94=20TC=20Stri?=
 =?UTF-8?q?ng=20encoder=20+=20purpose=20mapping=20+=20UI?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- TCFEncoderService: generates base64url-encoded TC Strings per IAB spec
  with 12 purposes, vendor consent bitfield, CMP metadata
- Category-to-purpose mapping (necessary→none, statistics→1,7,8,9,10,
  marketing→1,2,3,4,5,6,7,12, functional→1,11)
- tcf_routes: 5 endpoints (purposes, features, mapping, encode, encode-categories)
- banner_consent_service: auto-generates TC String when tcf_enabled=true
- TCFSettings.tsx: enable/disable toggle, purpose grid with category mapping,
  TC String test generator, CMP registration info
- New "TCF/IAB" tab in cookie-banner page (7 tabs total)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 .../cookie-banner/_components/TCFSettings.tsx | 161 ++++++++++++++
 .../app/sdk/cookie-banner/page.tsx            |  18 +-
 backend-compliance/compliance/api/__init__.py |   1 +
 .../compliance/api/tcf_routes.py              |  95 ++++++++
 .../services/banner_consent_service.py        |  22 ++
 .../services/tcf_encoder_service.py           | 209 ++++++++++++++++++
 6 files changed, 505 insertions(+), 1 deletion(-)
 create mode 100644 admin-compliance/app/sdk/cookie-banner/_components/TCFSettings.tsx
 create mode 100644 backend-compliance/compliance/api/tcf_routes.py
 create mode 100644 backend-compliance/compliance/services/tcf_encoder_service.py

diff --git a/admin-compliance/app/sdk/cookie-banner/_components/TCFSettings.tsx b/admin-compliance/app/sdk/cookie-banner/_components/TCFSettings.tsx
new file mode 100644
index 0000000..6448309
--- /dev/null
+++ b/admin-compliance/app/sdk/cookie-banner/_components/TCFSettings.tsx
@@ -0,0 +1,161 @@
+'use client'
+
+import { useState, useEffect } from 'react'
+
+interface IABPurpose {
+  id: number
+  name: string
+  name_de: string
+}
+
+const API = '/api/sdk/v1/compliance/tcf'
+
+export function TCFSettings({ siteId, tcfEnabled, onToggle }: {
+  siteId?: string
+  tcfEnabled: boolean
+  onToggle: (enabled: boolean) => void
+}) {
+  const [purposes, setPurposes] = useState<IABPurpose[]>([])
+  const [categoryMap, setCategoryMap] = useState<Record<string, number[]>>({})
+  const [testResult, setTestResult] = useState<string | null>(null)
+  const [testing, setTesting] = useState(false)
+
+  useEffect(() => {
+    Promise.all([
+      fetch(`${API}/purposes`).then(r => r.ok ? r.json() : []),
+      fetch(`${API}/category-mapping`).then(r => r.ok ? r.json() : {}),
+    ]).then(([p, m]) => {
+      setPurposes(p)
+      setCategoryMap(m)
+    }).catch(() => {})
+  }, [])
+
+  const handleTestEncode = async () => {
+    setTesting(true)
+    setTestResult(null)
+    try {
+      const res = await fetch(`${API}/encode-categories`, {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ categories: ['necessary', 'statistics', 'marketing'] }),
+      })
+      if (res.ok) {
+        const data = await res.json()
+        setTestResult(`TC String: ${data.tc_string}\nPurposes: ${data.purposes_consented.join(', ')}`)
+      }
+    } catch { setTestResult('Fehler beim Generieren') }
+    setTesting(false)
+  }
+
+  return (
+    <div className="space-y-6">
+      {/* Enable/Disable */}
+      <div className="bg-white rounded-xl border border-gray-200 p-6">
+        <div className="flex items-center justify-between">
+          <div>
+            <h3 className="font-semibold text-gray-900">IAB TCF 2.2</h3>
+            <p className="text-xs text-gray-500 mt-1">
+              Transparency & Consent Framework — Standardisierte Einwilligungssignale fuer programmatische Werbung
+            </p>
+          </div>
+          <label className="flex items-center gap-2">
+            <input type="checkbox" checked={tcfEnabled} onChange={e => onToggle(e.target.checked)}
+              className="w-5 h-5 text-purple-600 rounded" />
+            <span className="text-sm font-medium">{tcfEnabled ? 'Aktiv' : 'Inaktiv'}</span>
+          </label>
+        </div>
+        {!tcfEnabled && (
+          <p className="mt-3 text-xs text-amber-600 bg-amber-50 p-3 rounded-lg">
+            TCF ist nur erforderlich wenn Sie programmatische Werbung (AdTech) einsetzen.
+            Fuer die meisten Websites reicht das Standard-Cookie-Banner.
+          </p>
+        )}
+      </div>
+
+      {tcfEnabled && (
+        <>
+          {/* IAB Purposes */}
+          <div className="bg-white rounded-xl border border-gray-200 p-6">
+            <h4 className="font-semibold text-gray-900 mb-3">12 IAB-Zwecke (Purposes)</h4>
+            <p className="text-xs text-gray-500 mb-4">
+              Diese Zwecke werden automatisch aus Ihren Cookie-Kategorien abgeleitet.
+            </p>
+            <div className="grid grid-cols-1 md:grid-cols-2 gap-2">
+              {purposes.map(p => {
+                const activeCats = Object.entries(categoryMap)
+                  .filter(([, pids]) => pids.includes(p.id))
+                  .map(([cat]) => cat)
+                return (
+                  <div key={p.id} className={`flex items-start gap-2 p-2 rounded-lg text-xs ${activeCats.length > 0 ? 'bg-green-50' : 'bg-gray-50'}`}>
+                    <span className={`w-5 h-5 rounded-full flex items-center justify-center text-[10px] font-bold flex-shrink-0 ${activeCats.length > 0 ? 'bg-green-500 text-white' : 'bg-gray-300 text-white'}`}>
+                      {p.id}
+                    </span>
+                    <div>
+                      <div className="font-medium text-gray-700">{p.name_de}</div>
+                      {activeCats.length > 0 && (
+                        <div className="text-gray-400 mt-0.5">via: {activeCats.join(', ')}</div>
+                      )}
+                    </div>
+                  </div>
+                )
+              })}
+            </div>
+          </div>
+
+          {/* Category Mapping */}
+          <div className="bg-white rounded-xl border border-gray-200 p-6">
+            <h4 className="font-semibold text-gray-900 mb-3">Kategorie → Purpose Zuordnung</h4>
+            <div className="space-y-2">
+              {Object.entries(categoryMap).map(([cat, pids]) => (
+                <div key={cat} className="flex items-center gap-3">
+                  <span className="text-sm font-medium text-gray-700 w-24 capitalize">{cat}</span>
+                  <div className="flex gap-1 flex-wrap">
+                    {pids.length === 0 ? (
+                      <span className="text-xs text-gray-400">Keine Einwilligung noetig</span>
+                    ) : (
+                      pids.map(pid => (
+                        <span key={pid} className="px-2 py-0.5 text-[10px] bg-purple-100 text-purple-700 rounded-full">
+                          Purpose {pid}
+                        </span>
+                      ))
+                    )}
+                  </div>
+                </div>
+              ))}
+            </div>
+          </div>
+
+          {/* TC String Test */}
+          <div className="bg-white rounded-xl border border-gray-200 p-6">
+            <h4 className="font-semibold text-gray-900 mb-3">TC String testen</h4>
+            <button onClick={handleTestEncode} disabled={testing}
+              className="px-4 py-2 text-sm bg-purple-600 text-white rounded-lg hover:bg-purple-700 disabled:opacity-50">
+              {testing ? 'Generiere...' : 'Test TC String generieren'}
+            </button>
+            {testResult && (
+              <pre className="mt-3 p-3 bg-gray-50 border border-gray-200 rounded-lg text-xs text-gray-700 overflow-x-auto whitespace-pre-wrap">
+                {testResult}
+              </pre>
+            )}
+            <p className="text-xs text-gray-400 mt-2">
+              Simuliert: necessary + statistics + marketing → generiert base64url-codierten TC String
+            </p>
+          </div>
+
+          {/* CMP Registration Info */}
+          <div className="bg-blue-50 border border-blue-200 rounded-xl p-4">
+            <h4 className="font-semibold text-blue-800 text-sm">CMP-Registrierung</h4>
+            <p className="text-xs text-blue-700 mt-1">
+              Fuer den produktiven Einsatz muss Ihr CMP bei der IAB Europe registriert werden.
+              Sie erhalten eine eindeutige CMP-ID die im TC String codiert wird.
+            </p>
+            <p className="text-xs text-blue-600 mt-2">
+              Registrierung: <a href="https://iabeurope.eu/tcf-for-cmps/" target="_blank" rel="noopener"
+                className="underline">iabeurope.eu/tcf-for-cmps</a>
+            </p>
+          </div>
+        </>
+      )}
+    </div>
+  )
+}
diff --git a/admin-compliance/app/sdk/cookie-banner/page.tsx b/admin-compliance/app/sdk/cookie-banner/page.tsx
index c2196c5..cfcf14e 100644
--- a/admin-compliance/app/sdk/cookie-banner/page.tsx
+++ b/admin-compliance/app/sdk/cookie-banner/page.tsx
@@ -11,8 +11,9 @@ import { EmbeddableVendorHTML } from './_components/EmbeddableVendorHTML'
 import { SiteSelector } from './_components/SiteSelector'
 import { AnalyticsDashboard } from './_components/AnalyticsDashboard'
 import { ABTestPanel } from './_components/ABTestPanel'
+import { TCFSettings } from './_components/TCFSettings'
 
-type BannerTab = 'config' | 'vendors' | 'embed' | 'analytics' | 'abtest'
+type BannerTab = 'config' | 'vendors' | 'embed' | 'analytics' | 'abtest' | 'tcf'
 
 export default function CookieBannerPage() {
   const { state } = useSDK()
@@ -79,6 +80,7 @@ export default function CookieBannerPage() {
           { id: 'embed' as const, label: 'Einbettung' },
           { id: 'analytics' as const, label: 'Analytik' },
           { id: 'abtest' as const, label: 'A/B-Test' },
+          { id: 'tcf' as const, label: 'TCF/IAB' },
         ]).map(tab => (
           <button key={tab.id} onClick={() => setActiveTab(tab.id)}
             className={`px-4 py-3 text-sm font-medium border-b-2 -mb-px transition-colors ${
@@ -101,6 +103,20 @@ export default function CookieBannerPage() {
       {/* Tab: A/B-Test */}
       {activeTab === 'abtest' && <ABTestPanel siteConfigId={activeSiteId || undefined} />}
 
+      {/* Tab: TCF/IAB */}
+      {activeTab === 'tcf' && (
+        <TCFSettings siteId={activeSiteId || undefined} tcfEnabled={false}
+          onToggle={(enabled) => {
+            if (activeSiteId) {
+              fetch(`/api/sdk/v1/banner/admin/sites/${activeSiteId}`, {
+                method: 'PUT', headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify({ tcf_enabled: enabled }),
+              })
+            }
+          }}
+        />
+      )}
+
       {/* Tab: Konfiguration */}
       {activeTab !== 'config' ? null : (<>
       {/* Stats */}
diff --git a/backend-compliance/compliance/api/__init__.py b/backend-compliance/compliance/api/__init__.py
index fbd0deb..20ecdb2 100644
--- a/backend-compliance/compliance/api/__init__.py
+++ b/backend-compliance/compliance/api/__init__.py
@@ -69,6 +69,7 @@ _ROUTER_MODULES = [
     "banner_ab_routes",
     "compliance_report_routes",
     "whistleblower_routes",
+    "tcf_routes",
 ]
 
 _loaded_count = 0
diff --git a/backend-compliance/compliance/api/tcf_routes.py b/backend-compliance/compliance/api/tcf_routes.py
new file mode 100644
index 0000000..acc7f2b
--- /dev/null
+++ b/backend-compliance/compliance/api/tcf_routes.py
@@ -0,0 +1,95 @@
+"""
+FastAPI routes for IAB TCF 2.2 (Transparency & Consent Framework).
+
+Endpoints:
+  GET  /tcf/purposes          — list 12 IAB purposes with translations
+  GET  /tcf/special-features  — list 2 IAB special features
+  GET  /tcf/category-mapping  — banner category → IAB purpose mapping
+  POST /tcf/encode            — generate TC String from consent decisions
+  POST /tcf/encode-categories — generate TC String from banner categories
+"""
+
+import logging
+from typing import Optional, List, Dict
+
+from fastapi import APIRouter, Depends
+from pydantic import BaseModel
+from sqlalchemy.orm import Session
+
+from classroom_engine.database import get_db
+from .tenant_utils import get_tenant_id as _get_tenant_id
+from compliance.services.tcf_encoder_service import TCFEncoderService
+
+logger = logging.getLogger(__name__)
+router = APIRouter(prefix="/tcf", tags=["tcf"])
+
+
+class TCFEncodeRequest(BaseModel):
+    purpose_consents: Dict[int, bool] = {}
+    vendor_consents: Dict[int, bool] = {}
+    purpose_li: Optional[Dict[int, bool]] = None
+    special_features: Optional[Dict[int, bool]] = None
+    cmp_id: int = 1
+    cmp_version: int = 1
+    consent_language: str = "DE"
+
+
+class TCFCategoryEncodeRequest(BaseModel):
+    categories: List[str] = []
+    vendor_consents: Optional[Dict[int, bool]] = None
+    cmp_id: int = 1
+    consent_language: str = "DE"
+
+
+@router.get("/purposes")
+def list_purposes():
+    return TCFEncoderService.get_purposes()
+
+
+@router.get("/special-features")
+def list_special_features():
+    return TCFEncoderService.get_special_features()
+
+
+@router.get("/category-mapping")
+def get_category_mapping():
+    return TCFEncoderService.get_category_purpose_map()
+
+
+@router.post("/encode")
+def encode_tc_string(body: TCFEncodeRequest):
+    encoder = TCFEncoderService(
+        cmp_id=body.cmp_id,
+        cmp_version=body.cmp_version,
+        consent_language=body.consent_language,
+    )
+    tc_string = encoder.encode(
+        purpose_consents=body.purpose_consents,
+        vendor_consents=body.vendor_consents,
+        purpose_li=body.purpose_li,
+        special_features=body.special_features,
+    )
+    return {"tc_string": tc_string, "version": 2}
+
+
+@router.post("/encode-categories")
+def encode_from_categories(body: TCFCategoryEncodeRequest):
+    encoder = TCFEncoderService(
+        cmp_id=body.cmp_id,
+        consent_language=body.consent_language,
+    )
+    tc_string = encoder.encode_from_categories(
+        categories=body.categories,
+        vendor_consents=body.vendor_consents,
+    )
+    # Also return which purposes were set
+    from compliance.services.tcf_encoder_service import CATEGORY_PURPOSE_MAP
+    purpose_ids = set()
+    for cat in body.categories:
+        purpose_ids.update(CATEGORY_PURPOSE_MAP.get(cat, []))
+    return {
+        "tc_string": tc_string,
+        "version": 2,
+        "purposes_consented": sorted(purpose_ids),
+        "categories": body.categories,
+    }
diff --git a/backend-compliance/compliance/services/banner_consent_service.py b/backend-compliance/compliance/services/banner_consent_service.py
index f494fb1..51dffb8 100644
--- a/backend-compliance/compliance/services/banner_consent_service.py
+++ b/backend-compliance/compliance/services/banner_consent_service.py
@@ -133,6 +133,24 @@ class BannerConsentService:
             return max(v.retention_days for v in vendors if v.retention_days)
         return max((CATEGORY_RETENTION_DAYS.get(c, 365) for c in categories), default=365)
 
+    def _maybe_generate_tc_string(
+        self, tenant_id: uuid.UUID, site_id: str, categories: list[str],
+    ) -> Optional[str]:
+        """Generate TC String if TCF is enabled for this site."""
+        config = (
+            self.db.query(BannerSiteConfigDB)
+            .filter(BannerSiteConfigDB.tenant_id == tenant_id, BannerSiteConfigDB.site_id == site_id)
+            .first()
+        )
+        if not config or not config.tcf_enabled:
+            return None
+        try:
+            from compliance.services.tcf_encoder_service import TCFEncoderService
+            encoder = TCFEncoderService()
+            return encoder.encode_from_categories(categories)
+        except Exception:
+            return None
+
     # ------------------------------------------------------------------
     # Consent CRUD (public SDK)
     # ------------------------------------------------------------------
@@ -163,6 +181,10 @@ class BannerConsentService:
         expires_at = now + timedelta(days=retention)
         config_hash, config_ver = self._compute_config_hash(tid, site_id)
 
+        # Auto-generate TC String if TCF is enabled for this site
+        if not consent_string:
+            consent_string = self._maybe_generate_tc_string(tid, site_id, categories)
+
         existing = (
             self.db.query(BannerConsentDB)
             .filter(
diff --git a/backend-compliance/compliance/services/tcf_encoder_service.py b/backend-compliance/compliance/services/tcf_encoder_service.py
new file mode 100644
index 0000000..5eb2ae7
--- /dev/null
+++ b/backend-compliance/compliance/services/tcf_encoder_service.py
@@ -0,0 +1,209 @@
+"""
+TCF 2.2 TC String Encoder — generates IAB Transparency & Consent strings.
+
+Implements the TC String v2.2 format per IAB specification.
+The TC String is a base64url-encoded bitfield containing:
+- CMP metadata (ID, version, screen, consent language)
+- Purpose consents (12 standard IAB purposes)
+- Vendor consents (per IAB vendor ID)
+- Legitimate interest signals
+
+Reference: https://github.com/InteractiveAdvertisingBureau/GDPR-Transparency-and-Consent-Framework
+
+NOTE: This is a simplified encoder for CMP integration. For full GVL
+(Global Vendor List) support, integrate with the IAB GVL API.
+"""
+
+import base64
+import math
+from datetime import datetime, timezone
+from typing import Any
+
+
+# IAB TCF 2.2 Standard Purposes
+IAB_PURPOSES = {
+    1: {"name": "Store and/or access information on a device", "name_de": "Informationen auf Geraet speichern/abrufen"},
+    2: {"name": "Select basic ads", "name_de": "Einfache Anzeigen auswaehlen"},
+    3: {"name": "Create a personalised ads profile", "name_de": "Personalisiertes Anzeigenprofil erstellen"},
+    4: {"name": "Select personalised ads", "name_de": "Personalisierte Anzeigen auswaehlen"},
+    5: {"name": "Create a personalised content profile", "name_de": "Personalisiertes Inhaltsprofil erstellen"},
+    6: {"name": "Select personalised content", "name_de": "Personalisierte Inhalte auswaehlen"},
+    7: {"name": "Measure ad performance", "name_de": "Anzeigen-Leistung messen"},
+    8: {"name": "Measure content performance", "name_de": "Inhalte-Leistung messen"},
+    9: {"name": "Apply market research to generate audience insights", "name_de": "Marktforschung fuer Zielgruppen"},
+    10: {"name": "Develop and improve products", "name_de": "Produkte entwickeln und verbessern"},
+    11: {"name": "Use limited data to select content", "name_de": "Eingeschraenkte Daten fuer Inhalte nutzen"},
+    12: {"name": "Use limited data to select ads", "name_de": "Eingeschraenkte Daten fuer Anzeigen nutzen"},
+}
+
+# IAB Special Features
+IAB_SPECIAL_FEATURES = {
+    1: {"name": "Use precise geolocation data", "name_de": "Praezise Standortdaten verwenden"},
+    2: {"name": "Actively scan device characteristics for identification", "name_de": "Geraetemerkmale aktiv scannen"},
+}
+
+# Category-to-Purpose mapping (how our banner categories map to IAB purposes)
+CATEGORY_PURPOSE_MAP = {
+    "necessary": [],  # No consent needed
+    "functional": [1, 11],  # Device access + limited data for content
+    "statistics": [1, 7, 8, 9, 10],  # Device access + measurement + research
+    "marketing": [1, 2, 3, 4, 5, 6, 7, 12],  # Most purposes
+}
+
+
+def _int_to_bits(value: int, length: int) -> str:
+    """Convert integer to fixed-length bit string."""
+    return bin(value)[2:].zfill(length)
+
+
+def _datetime_to_deciseconds(dt: datetime) -> int:
+    """Convert datetime to deciseconds since epoch (IAB format)."""
+    epoch = datetime(2000, 1, 1, tzinfo=timezone.utc)
+    return int((dt - epoch).total_seconds() * 10)
+
+
+def _bits_to_base64url(bits: str) -> str:
+    """Convert bit string to base64url encoding (TC String format)."""
+    # Pad to multiple of 8
+    padding = (8 - len(bits) % 8) % 8
+    bits += "0" * padding
+    # Convert to bytes
+    byte_array = bytearray()
+    for i in range(0, len(bits), 8):
+        byte_array.append(int(bits[i:i+8], 2))
+    # Base64url encode (no padding)
+    return base64.urlsafe_b64encode(bytes(byte_array)).rstrip(b"=").decode("ascii")
+
+
+class TCFEncoderService:
+    """Generates TC Strings per IAB TCF 2.2 specification."""
+
+    def __init__(
+        self,
+        cmp_id: int = 1,
+        cmp_version: int = 1,
+        consent_screen: int = 1,
+        consent_language: str = "DE",
+    ):
+        self.cmp_id = cmp_id
+        self.cmp_version = cmp_version
+        self.consent_screen = consent_screen
+        self.consent_language = consent_language
+
+    def encode(
+        self,
+        purpose_consents: dict[int, bool],
+        vendor_consents: dict[int, bool],
+        purpose_li: dict[int, bool] | None = None,
+        special_features: dict[int, bool] | None = None,
+    ) -> str:
+        """Generate a TC String from consent decisions.
+
+        Args:
+            purpose_consents: {purpose_id: True/False} for purposes 1-12
+            vendor_consents: {vendor_id: True/False} for IAB vendor IDs
+            purpose_li: Legitimate interest signals per purpose
+            special_features: Special feature opt-ins
+        Returns:
+            Base64url-encoded TC String
+        """
+        now = datetime.now(timezone.utc)
+        created = _datetime_to_deciseconds(now)
+        updated = created
+
+        bits = ""
+        # Core TC String v2 fields
+        bits += _int_to_bits(2, 6)                    # Version (6 bits) = 2
+        bits += _int_to_bits(created, 36)              # Created (36 bits)
+        bits += _int_to_bits(updated, 36)              # LastUpdated (36 bits)
+        bits += _int_to_bits(self.cmp_id, 12)          # CmpId (12 bits)
+        bits += _int_to_bits(self.cmp_version, 12)     # CmpVersion (12 bits)
+        bits += _int_to_bits(self.consent_screen, 6)   # ConsentScreen (6 bits)
+
+        # ConsentLanguage (12 bits = 2 × 6-bit letters)
+        lang = self.consent_language.upper()[:2]
+        bits += _int_to_bits(ord(lang[0]) - ord("A"), 6)
+        bits += _int_to_bits(ord(lang[1]) - ord("A"), 6)
+
+        # VendorListVersion (12 bits) — use 0 if not fetching GVL
+        bits += _int_to_bits(0, 12)
+        # TcfPolicyVersion (6 bits) = 4 for TCF 2.2
+        bits += _int_to_bits(4, 6)
+        # IsServiceSpecific (1 bit) = 1
+        bits += "1"
+        # UseNonStandardTexts (1 bit) = 0
+        bits += "0"
+
+        # SpecialFeatureOptIns (12 bits)
+        sf = special_features or {}
+        for i in range(1, 13):
+            bits += "1" if sf.get(i, False) else "0"
+
+        # PurposesConsent (24 bits)
+        for i in range(1, 25):
+            bits += "1" if purpose_consents.get(i, False) else "0"
+
+        # PurposesLITransparency (24 bits)
+        li = purpose_li or {}
+        for i in range(1, 25):
+            bits += "1" if li.get(i, False) else "0"
+
+        # Purpose one treatment (1 bit) = 0, PublisherCC (12 bits) = DE
+        bits += "0"
+        bits += _int_to_bits(ord("D") - ord("A"), 6)
+        bits += _int_to_bits(ord("E") - ord("A"), 6)
+
+        # Vendor consents — Range encoding
+        max_vendor = max(vendor_consents.keys()) if vendor_consents else 0
+        bits += _int_to_bits(max_vendor, 16)  # MaxVendorId
+        # Use bitfield encoding (simpler than range)
+        bits += "0"  # IsRangeEncoding = 0 (bitfield)
+        for i in range(1, max_vendor + 1):
+            bits += "1" if vendor_consents.get(i, False) else "0"
+
+        # Vendor legitimate interests (same pattern)
+        bits += _int_to_bits(max_vendor, 16)
+        bits += "0"
+        for i in range(1, max_vendor + 1):
+            bits += "1" if vendor_consents.get(i, False) else "0"  # Simplified: same as consent
+
+        return _bits_to_base64url(bits)
+
+    def encode_from_categories(
+        self,
+        categories: list[str],
+        vendor_consents: dict[int, bool] | None = None,
+    ) -> str:
+        """Generate TC String from banner category selections.
+
+        Maps our banner categories (necessary, statistics, marketing, functional)
+        to IAB purposes and generates the TC String.
+        """
+        purpose_consents: dict[int, bool] = {}
+        for cat in categories:
+            for purpose_id in CATEGORY_PURPOSE_MAP.get(cat, []):
+                purpose_consents[purpose_id] = True
+
+        return self.encode(
+            purpose_consents=purpose_consents,
+            vendor_consents=vendor_consents or {},
+        )
+
+    @staticmethod
+    def get_purposes() -> list[dict[str, Any]]:
+        """Return all 12 IAB purposes with translations."""
+        return [
+            {"id": pid, "name": info["name"], "name_de": info["name_de"]}
+            for pid, info in IAB_PURPOSES.items()
+        ]
+
+    @staticmethod
+    def get_special_features() -> list[dict[str, Any]]:
+        return [
+            {"id": fid, "name": info["name"], "name_de": info["name_de"]}
+            for fid, info in IAB_SPECIAL_FEATURES.items()
+        ]
+
+    @staticmethod
+    def get_category_purpose_map() -> dict[str, list[int]]:
+        return CATEGORY_PURPOSE_MAP