{"product_id":"vag-sync-calculator","title":"VAG Sync Calculator","description":"\u003cp\u003e\u003cmeta charset=\"UTF-8\"\u003e \u003cmeta content=\"width=device-width, initial-scale=1.0\" name=\"viewport\"\u003e\u003clink href=\"https:\/\/fonts.googleapis.com\" rel=\"preconnect\"\u003e \u003clink crossorigin=\"\" href=\"https:\/\/fonts.gstatic.com\" rel=\"preconnect\"\u003e \u003clink rel=\"stylesheet\" href=\"https:\/\/fonts.googleapis.com\/css2?family=Ubuntu:wght@400;500;700\u0026amp;display=swap\"\u003e\u003c\/p\u003e\n\u003cstyle\u003e\n \/* ============================================\n VAG Sync Tool — keylibrary.co.uk Theme\n Design tokens from keylibrary.co.uk:\n - Primary accent: #ef5729 (orange-red)\n - Secondary accent: #0f9d58 (green)\n - Background: #ffffff\n - Text: rgba(51,51,51,0.75)\n - Card bg: #ffffff, border: rgba(51,51,51,0.1)\n - Fonts: Playfair Display (headings), Lato (body)\n - Accent: #F05A28 (orange-red)\n ============================================ *\/\n .vag-sync-tool {\n \/* keylibrary colour tokens *\/\n --color-bg: #ffffff;\n --color-surface: #f8f8f8;\n --color-card: #ffffff;\n --color-card-border: rgba(51,51,51,0.1);\n --color-text: rgba(51,51,51,0.75);\n --color-text-muted: rgba(51,51,51,0.55);\n --color-text-strong: rgb(51,51,51);\n --color-accent: #ef5729;\n --color-accent-hover: #d44a23;\n --color-accent-glow: rgba(239,87,41,0.25);\n --color-success: #11ae66;\n --color-success-glow: rgba(17,174,102,0.2);\n --color-error: #c0392b;\n --color-warning-bg: #fff9f0;\n --color-warning-border: #ef5729;\n --color-border: rgba(51,51,51,0.15);\n --color-input-bg: #f5f5f5;\n --color-input-border: rgba(51,51,51,0.2);\n --color-input-focus: #ef5729;\n --shadow-card: 0 2px 8px rgba(51,51,51,0.08), 0 1px 2px rgba(51,51,51,0.04);\n --shadow-card-hover: 0 4px 16px rgba(51,51,51,0.12), 0 2px 4px rgba(51,51,51,0.06);\n --radius-sm: 6px;\n --radius-md: 10px;\n --radius-lg: 14px;\n --font-heading: 'Ubuntu', 'Segoe UI', sans-serif;\n --font-body: 'Ubuntu', 'Segoe UI', sans-serif;\n --font-mono: 'Ubuntu', monospace;\n --transition: 0.2s ease;\n }\n .vag-sync-tool * { box-sizing: border-box; margin: 0; padding: 0; }\n .vag-sync-tool body {\n font-family: var(--font-body);\n max-width: 700px;\n margin: 0 auto;\n padding: 30px 20px 60px;\n background: var(--color-bg);\n color: var(--color-text);\n min-height: 100vh;\n -webkit-font-smoothing: antialiased;\n }\n\n \/* Header *\/\n .vag-sync-tool .header {\n text-align: center;\n margin-bottom: 0;\n padding-bottom: 0;\n border-bottom: none;\n }\n .vag-sync-tool .header .subtitle {\n color: rgba(51,51,51,0.7);\n font-size: 12px;\n font-weight: 400;\n text-transform: uppercase;\n letter-spacing: 3px;\n }\n\n \/* Mode toggle *\/\n .vag-sync-tool .mode-toggle {\n display: flex;\n margin-bottom: 24px;\n background: var(--color-surface);\n border: 1px solid var(--color-border);\n border-radius: var(--radius-md);\n padding: 4px;\n }\n .vag-sync-tool .mode-btn {\n flex: 1;\n padding: 11px 20px;\n border: none;\n background: transparent;\n color: var(--color-text-muted);\n cursor: pointer;\n border-radius: var(--radius-sm);\n font-family: var(--font-body);\n font-size: 13px;\n font-weight: 400;\n text-transform: uppercase;\n letter-spacing: 1.2px;\n transition: all var(--transition);\n }\n .vag-sync-tool .mode-btn.active {\n background: rgb(239,87,41);\n color: #ffffff;\n }\n .vag-sync-tool .mode-btn:hover:not(.active) {\n color: var(--color-text-strong);\n background: rgba(51,51,51,0.05);\n }\n\n \/* Card *\/\n .vag-sync-tool .card {\n background: var(--color-card);\n border-radius: var(--radius-lg);\n padding: 24px;\n margin-bottom: 18px;\n }\n .vag-sync-tool .card-title {\n color: var(--color-accent);\n font-size: 11px;\n font-weight: 700;\n text-transform: uppercase;\n letter-spacing: 2.5px;\n margin-bottom: 20px;\n padding-bottom: 12px;\n border-bottom: 1px solid var(--color-border);\n }\n\n \/* Field *\/\n .vag-sync-tool .field { margin-bottom: 16px; }\n .vag-sync-tool label {\n display: block;\n margin-bottom: 12px !important;\n font-weight: 400;\n color: var(--color-text-muted);\n font-size: 11px;\n text-transform: uppercase;\n letter-spacing: 1px;\n }\n .vag-sync-tool input[type=\"text\"] {\n width: 100%;\n padding: 13px 15px;\n border: 0;\n border-radius: var(--radius-sm);\n background: #ffffff;\n color: rgb(51,51,51);\n font-family: var(--font-mono);\n font-size: 15px;\n letter-spacing: 1px;\n box-shadow: inset 0 1px 3px rgba(51,51,51,0.06);\n transition: box-shadow var(--transition);\n }\n .vag-sync-tool input[type=\"text\"]:focus {\n outline: .2rem solid rgba(51,51,51,0.5);\n outline-offset: 3px;\n box-shadow: inset 0 1px 3px rgba(51,51,51,0.06), 0 0 0 3px rgba(51,51,51,0.1);\n }\n .vag-sync-tool input[type=\"text\"]::placeholder { color: rgba(51,51,51,0.3); }\n .vag-sync-tool input[type=\"text\"]:disabled {\n background: var(--color-surface);\n color: rgba(51,51,51,0.35);\n cursor: not-allowed;\n box-shadow: none;\n }\n .vag-sync-tool input[type=\"text\"][readonly] {\n background: var(--color-surface);\n color: var(--color-text-strong);\n border-color: var(--color-border);\n cursor: default;\n }\n .vag-sync-tool input[type=\"text\"][readonly]:focus {\n box-shadow: none;\n }\n .vag-sync-tool .mono-field {\n font-family: var(--font-mono) !important;\n letter-spacing: 1px !important;\n }\n\n \/* Checkbox *\/\n .vag-sync-tool .checkbox-container {\n display: flex;\n align-items: center;\n gap: 12px;\n margin-bottom: 13px;\n padding: 13px 15px;\n background: var(--color-surface);\n border: 1px solid var(--color-border);\n border-radius: var(--radius-sm);\n cursor: pointer;\n transition: all var(--transition);\n }\n .vag-sync-tool .checkbox-container:hover {\n background: rgba(239,87,41,0.04);\n border-color: rgba(239,87,41,0.25);\n }\n .vag-sync-tool .checkbox-container input[type=\"checkbox\"] {\n width: 20px;\n height: 20px;\n accent-color: var(--color-accent);\n cursor: pointer;\n flex-shrink: 0;\n }\n .vag-sync-tool .checkbox-container span {\n margin: 0;\n color: var(--color-text);\n font-size: 14px;\n font-weight: 400;\n text-transform: none;\n letter-spacing: 0;\n cursor: pointer;\n }\n .vag-sync-tool .checkbox-container.ev-coming-soon label {\n color: var(--color-text-muted);\n cursor: not-allowed;\n font-style: italic;\n }\n .vag-sync-tool .checkbox-container.ev-coming-soon {\n opacity: 0.7;\n cursor: default;\n }\n .vag-sync-tool .checkbox-container.ev-coming-soon:hover {\n background: var(--color-surface);\n border-color: var(--color-border);\n }\n\n \/* Buttons *\/\n .vag-sync-tool .btn {\n padding: 14px 28px;\n border: none;\n border-radius: var(--radius-sm);\n cursor: pointer;\n font-family: var(--font-body);\n font-size: 15px;\n font-weight: 400;\n letter-spacing: .1rem;\n text-transform: none;\n transition: box-shadow var(--transition);\n width: 100%;\n }\n .vag-sync-tool .btn-primary {\n background: rgb(239,87,41);\n color: #ffffff;\n }\n .vag-sync-tool .btn-primary:hover {\n background: #d44a23;\n }\n .vag-sync-tool .btn-primary:active {\n background: #c04020;\n }\n .vag-sync-tool .btn-secondary {\n background: var(--color-surface);\n color: var(--color-text-muted);\n border: 1px solid var(--color-border);\n }\n .vag-sync-tool .btn-secondary:hover {\n background: var(--color-card);\n color: var(--color-text-strong);\n border-color: var(--color-text-muted);\n }\n\n \/* Result *\/\n .vag-sync-tool .result {\n margin-top: 18px;\n padding: 20px;\n background: var(--color-surface);\n border-radius: var(--radius-md);\n border-left: 4px solid var(--color-success);\n }\n .vag-sync-tool .result-error {\n border-left-color: var(--color-error);\n background: #fff8f8;\n }\n .vag-sync-tool .result-title {\n color: var(--color-accent);\n font-size: 10px;\n font-weight: 700;\n text-transform: uppercase;\n letter-spacing: 2.5px;\n margin-bottom: 14px;\n }\n .vag-sync-tool .result-item { margin-bottom: 14px; }\n .vag-sync-tool .result-item:last-child { margin-bottom: 0; }\n .vag-sync-tool .result-label {\n color: var(--color-text-muted);\n font-size: 1rem;\n font-weight: 400;\n text-transform: none;\n letter-spacing: 0;\n margin-bottom: 5px;\n }\n .vag-sync-tool .result-value {\n color: var(--color-text-strong);\n font-family: var(--font-mono);\n font-size: 13px;\n background: var(--color-card);\n padding: 10px 13px;\n border-radius: var(--radius-sm);\n border: 1px solid var(--color-border);\n word-break: break-all;\n }\n .vag-sync-tool .sync-display {\n font-family: var(--font-mono);\n word-break: break-all;\n background: var(--color-card);\n padding: 14px;\n border-radius: var(--radius-sm);\n margin-top: 10px;\n font-size: 13px;\n color: var(--color-accent);\n letter-spacing: 1.5px;\n border: 1px solid var(--color-border);\n }\n .vag-sync-tool .file-controls {\n display: flex;\n gap: 10px;\n margin-top: 10px;\n }\n .vag-sync-tool .file-controls .btn {\n flex: 1;\n }\n .vag-sync-tool .instructions {\n margin-top: 30px;\n padding: 20px 25px;\n background: #252525;\n border-radius: 12px;\n font-size: 13px;\n line-height: 1.8;\n color: #aaa;\n }\n .vag-sync-tool .instructions h3 {\n color: #F2C232;\n font-size: 12px;\n text-transform: uppercase;\n letter-spacing: 2px;\n margin: 0 0 15px 0;\n }\n .vag-sync-tool .instructions p {\n margin: 0 0 10px 0;\n }\n .vag-sync-tool .instructions ul {\n margin: 0;\n padding-left: 20px;\n }\n .vag-sync-tool .instructions li {\n margin-bottom: 5px;\n }\n .vag-sync-tool .hidden {\n display: none;\n }\n\n \/* Inline style equivalents for vag-sync-tool *\/\n .vag-sync-tool .field-margin-top {\n margin-top: 15px;\n }\n .vag-sync-tool .file-input-hidden {\n display: none;\n }\n .vag-sync-tool .field2 {\n margin-bottom: 16px;\n }\n .vag-sync-tool .flex-row {\n display: flex;\n gap: 10px;\n align-items: center;\n margin-top: 8px;\n }\n .vag-sync-tool .flex-row input {\n flex: 1;\n min-width: 0;\n }\n .vag-sync-tool .flex-row .btn {\n width: auto;\n padding: 13px 16px;\n flex-shrink: 0;\n }\n @media (max-width: 600px) {\n .vag-sync-tool .flex-row {\n flex-direction: column;\n align-items: stretch;\n }\n .vag-sync-tool .flex-row input,\n .vag-sync-tool .flex-row .btn {\n width: 100% !important;\n flex: none !important;\n }\n }\n \u003c\/style\u003e\n\u003cdiv class=\"vag-sync-tool\"\u003e\n\u003cdiv class=\"header\"\u003e\u003c!-- Logo and branding hosted by parent keylibrary.co.uk --\u003e\u003c\/div\u003e\n\u003cdiv class=\"mode-toggle\"\u003e\n\u003cbutton class=\"mode-btn active\" id=\"btnForward\"\u003eForward Mode\u003c\/button\u003e \u003cbutton class=\"mode-btn\" id=\"btnReverse\"\u003eReverse Mode\u003c\/button\u003e\n\u003c\/div\u003e\n\u003cdiv id=\"forwardMode\"\u003e\n\u003cdiv class=\"card\"\u003e\n\u003cdiv class=\"card-title\"\u003eInput Parameters\u003c\/div\u003e\n\u003cdiv class=\"field2\"\u003e\n\u003clabel for=\"fwdImmo\"\u003eIMMO (Key)\u003c\/label\u003e\n\u003cdiv class=\"flex-row\"\u003e\n\u003cinput type=\"text\" id=\"fwdImmo\" placeholder=\"32 hex characters\" maxlength=\"32\"\u003e \u003cbutton class=\"btn btn-secondary\" id=\"btnLoadFwdImmo\"\u003eLoad .bin\u003c\/button\u003e \u003cinput type=\"file\" id=\"fileFwdImmo\" accept=\".bin\" class=\"file-input-hidden\"\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"field2 hidden\" id=\"fwdVINField\"\u003e\n\u003clabel for=\"fwdVIN\"\u003eVIN (from file)\u003c\/label\u003e \u003cinput type=\"text\" id=\"fwdVIN\" class=\"mono-field\" readonly\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"field2\"\u003e\n\u003clabel for=\"fwdECU\"\u003eECU\u003c\/label\u003e \u003cinput type=\"text\" id=\"fwdECU\" placeholder=\"32 hex characters\" maxlength=\"32\"\u003e\n\u003c\/div\u003e\n\u003clabel class=\"checkbox-container\" for=\"fwdTCUActive\"\u003e \u003cinput type=\"checkbox\" id=\"fwdTCUActive\"\u003e \u003cspan\u003eTCU Active\u003c\/span\u003e \u003c\/label\u003e\n\u003cdiv class=\"field2 hidden\" id=\"fwdTCUField\"\u003e\n\u003clabel for=\"fwdTCU\"\u003eTCU\u003c\/label\u003e \u003cinput type=\"text\" id=\"fwdTCU\" placeholder=\"32 hex characters\" maxlength=\"32\"\u003e\n\u003c\/div\u003e\n\u003clabel class=\"checkbox-container\" for=\"fwdELVActive\"\u003e \u003cinput type=\"checkbox\" id=\"fwdELVActive\"\u003e \u003cspan\u003eELV Active\u003c\/span\u003e \u003c\/label\u003e\n\u003cdiv class=\"field2 hidden\" id=\"fwdELVField\"\u003e\n\u003clabel for=\"fwdELV\"\u003eELV\u003c\/label\u003e \u003cinput type=\"text\" id=\"fwdELV\" placeholder=\"32 hex characters\" maxlength=\"32\"\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"checkbox-container disabled\"\u003e\n\u003cinput type=\"checkbox\" id=\"fwdEVActive\" disabled\u003e \u003clabel for=\"fwdEVActive\"\u003eEV (Coming Soon)\u003c\/label\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cbutton class=\"btn btn-primary\" id=\"btnCalcSync\"\u003eCalculate Sync\u003c\/button\u003e\n\u003c\/div\u003e\n\u003cdiv id=\"reverseMode\" class=\"hidden\"\u003e\n\u003cdiv class=\"card\"\u003e\n\u003cdiv class=\"card-title\"\u003eInput Data\u003c\/div\u003e\n\u003cdiv class=\"field2\"\u003e\n\u003clabel for=\"revSync\"\u003eSync\u003c\/label\u003e\n\u003cdiv class=\"flex-row\"\u003e\n\u003cinput type=\"text\" id=\"revSync\" placeholder=\"64 hex characters\" maxlength=\"64\"\u003e \u003cbutton class=\"btn btn-secondary\" id=\"btnLoadSync\"\u003eLoad Sync .bin\u003c\/button\u003e \u003cinput type=\"file\" id=\"fileSync\" accept=\".bin\" class=\"file-input-hidden\"\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"field2 field-margin-top\"\u003e\n\u003clabel for=\"revImmo\"\u003eIMMO (Key)\u003c\/label\u003e\n\u003cdiv class=\"flex-row\"\u003e\n\u003cinput type=\"text\" id=\"revImmo\" placeholder=\"32 hex characters\" maxlength=\"32\"\u003e \u003cbutton class=\"btn btn-secondary\" id=\"btnLoadRevImmo\"\u003eLoad .bin\u003c\/button\u003e \u003cinput type=\"file\" id=\"fileRevImmo\" accept=\".bin\" class=\"file-input-hidden\"\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"field2 hidden\" id=\"revVINField\"\u003e\n\u003clabel for=\"revVIN\"\u003eVIN (from file)\u003c\/label\u003e \u003cinput type=\"text\" id=\"revVIN\" class=\"mono-field\" readonly\u003e\n\u003c\/div\u003e\n\u003clabel class=\"checkbox-container\" for=\"revTCUActive\"\u003e \u003cinput type=\"checkbox\" id=\"revTCUActive\"\u003e \u003cspan\u003eTCU Active\u003c\/span\u003e \u003c\/label\u003e \u003clabel class=\"checkbox-container\" for=\"revELVActive\"\u003e \u003cinput type=\"checkbox\" id=\"revELVActive\"\u003e \u003cspan\u003eELV Active\u003c\/span\u003e \u003c\/label\u003e\n\u003c\/div\u003e\n\u003cbutton class=\"btn btn-primary\" id=\"btnReverseCalc\"\u003eReverse Calculate\u003c\/button\u003e\n\u003c\/div\u003e\n\u003cdiv id=\"result\" class=\"result hidden\"\u003e\u003c\/div\u003e\n\u003cdiv id=\"syncDownloadSection\" class=\"result hidden\"\u003e\n\u003cdiv class=\"result-title\"\u003eGenerated Sync\u003c\/div\u003e\n\u003cdiv class=\"sync-display\" id=\"syncDisplay\"\u003e\u003c\/div\u003e\n\u003cdiv class=\"file-controls\" style=\"margin-top: 15px;\"\u003e\u003cbutton class=\"btn btn-secondary\" id=\"btnDownloadSync\"\u003eDownload .bin\u003c\/button\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"card instructions\"\u003e\n\u003cdiv class=\"card-title\"\u003eHow to use\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eForward Mode:\u003c\/strong\u003e Enter IMMO and ECU, optionally TCU and\/or ELV. Click \"Calculate Sync\" to generate the sync bytes.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eReverse Mode:\u003c\/strong\u003e Enter Sync and IMMO. Click \"Reverse Calculate\" to recover ECU, TCU, ELV values. ⚠️ Experimental — under testing.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eNotes:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eAll values are 32 hex characters (16 bytes)\u003c\/li\u003e\n\u003cli\u003eTCU must be active to include TCU in calculation\u003c\/li\u003e\n\u003cli\u003eELV must be active to include ELV in calculation\u003c\/li\u003e\n\u003cli\u003eThe sync output is exactly 32 bytes\u003c\/li\u003e\n\u003cli\u003eDownload creates a .bin file with raw bytes\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp\u003e\u003cscript src=\"https:\/\/cdnjs.cloudflare.com\/ajax\/libs\/crypto-js\/4.1.1\/crypto-js.min.js\"\u003e\u003c\/script\u003e \u003cscript\u003e\n console.log('made by t0m1o1');\n document.getElementById('fwdEVActive').addEventListener('change', (e) =\u003e {\n document.getElementById('fwdEVField').classList.toggle('hidden', !e.target.checked);\n });\n function hexToBytes(hex) {\n hex = hex.replace(\/\\s\/g, '');\n const bytes = [];\n for (let i = 0; i \u003c hex.length; i += 2) {\n bytes.push(parseInt(hex.substr(i, 2), 16));\n }\n return new Uint8Array(bytes);\n }\n\n function bytesToHex(bytes) {\n return Array.from(bytes).map(b =\u003e b.toString(16).padStart(2, '0')).join('').toUpperCase();\n }\n\n \/\/ W permutation: byte shuffle used by VAG tool (self-inverse: W = W^-1)\n \/\/ Only applied when a[0] == 0x00 (determined empirically from reference vectors)\n const W_PERM = [14, 15, 12, 13, 10, 11, 8, 9, 6, 7, 4, 5, 2, 3, 0, 1];\n\n function applyW(block) {\n const result = new Uint8Array(16);\n for (let i = 0; i \u003c 16; i++) {\n result[i] = block[W_PERM[i]];\n }\n return result;\n }\n\n function aesEncrypt(keyBytes, blockBytes) {\n const key = CryptoJS.lib.WordArray.create(keyBytes);\n const plaintext = CryptoJS.lib.WordArray.create(blockBytes);\n const encrypted = CryptoJS.AES.encrypt(plaintext, key, { mode: CryptoJS.mode.ECB, padding: CryptoJS.pad.NoPadding });\n const cipherWords = encrypted.ciphertext;\n const result = new Uint8Array(16);\n for (let i = 0; i \u003c 16; i++) {\n result[i] = cipherWords.words[Math.floor(i \/ 4)] \u003e\u003e ((3 - (i % 4)) * 8) \u0026 0xFF;\n }\n return result;\n }\n\n function aesDecrypt(keyBytes, blockBytes) {\n const key = CryptoJS.lib.WordArray.create(keyBytes);\n const ciphertext = CryptoJS.lib.WordArray.create(blockBytes);\n const decrypted = CryptoJS.AES.decrypt({ ciphertext: ciphertext }, key, { mode: CryptoJS.mode.ECB, padding: CryptoJS.pad.NoPadding });\n const words = decrypted.words;\n const result = new Uint8Array(16);\n for (let i = 0; i \u003c 16; i++) {\n result[i] = words[Math.floor(i \/ 4)] \u003e\u003e ((3 - (i % 4)) * 8) \u0026 0xFF;\n }\n return result;\n }\n\n function calculateSync(immoHex, ecuHex, tcuHex, elvHex, tcuActive, elvActive) {\n const a = hexToBytes(immoHex);\n const b = hexToBytes(ecuHex);\n const c = tcuActive ? hexToBytes(tcuHex) : null;\n const d = elvActive ? hexToBytes(elvHex) : null;\n const X = crypto.getRandomValues(new Uint8Array(4));\n let P1, P2;\n\n if (elvActive \u0026\u0026 tcuActive) {\n P1 = aesEncrypt(a, d);\n P2 = new Uint8Array(16);\n P2.set(c.slice(0, 4), 0);\n P2.set(b.slice(4, 8), 4);\n P2.set(b.slice(8, 12), 8);\n P2.set(X, 12);\n P2 = aesEncrypt(a, P2);\n } else if (tcuActive) {\n \/\/ ELV not active: P1 = ECU (b), same as ECU-only case\n \/\/ P1 carries b's structure so reverse recovery works\n P1 = b.slice();\n P1 = aesEncrypt(a, P1);\n P2 = new Uint8Array(16);\n P2.set(c.slice(0, 4), 0);\n P2.set(b.slice(4, 8), 4);\n P2.set(b.slice(8, 12), 8);\n P2.set(X, 12);\n P2 = aesEncrypt(a, P2);\n } else if (elvActive) {\n P1 = aesEncrypt(a, d);\n P2 = new Uint8Array(16);\n P2.set(new Uint8Array(4), 0);\n P2.set(b.slice(4, 8), 4);\n P2.set(b.slice(8, 12), 8);\n P2.set(X, 12);\n P2 = aesEncrypt(a, P2);\n } else {\n P1 = b.slice(); \/\/ b is the ECU value, used as P1 when d is not active\n P1 = aesEncrypt(a, P1);\n P2 = new Uint8Array(16);\n P2.set(new Uint8Array(4), 0);\n P2.set(b.slice(4, 8), 4);\n P2.set(b.slice(8, 12), 8);\n P2.set(X, 12);\n P2 = aesEncrypt(a, P2);\n }\n\n const block1 = (a[0] === 0) ? applyW(P1) : P1;\n const block2 = (a[0] === 0) ? applyW(P2) : P2;\n const output = new Uint8Array(32);\n output.set(block1, 0);\n output.set(block2, 16);\n return bytesToHex(output);\n }\n\n \/\/ Overlap validation for forward mode\n \/\/ Validates that overlapping bytes between modules are consistent\n function checkOverlapWarnings(ecu, tcu, elv, tcuActive, elvActive) {\n const issues = [];\n \n \/\/ ECU and ELV overlap: ECU[0:4] === ELV[0:4] AND ECU[12:16] === ELV[12:16]\n if (elvActive \u0026\u0026 elv) {\n const ecu0_4 = ecu.substring(0, 8); \/\/ 4 bytes = 8 hex chars\n const elv0_4 = elv.substring(0, 8);\n const ecu12_16 = ecu.substring(24, 32); \/\/ 4 bytes = 8 hex chars\n const elv12_16 = elv.substring(24, 32);\n \n if (ecu0_4 !== elv0_4) {\n issues.push('ECU[0:4] !== ELV[0:4]');\n }\n if (ecu12_16 !== elv12_16) {\n issues.push('ECU[12:16] !== ELV[12:16]');\n }\n }\n \n \/\/ ECU and TCU overlap: ECU[8:12] === TCU[8:12]\n if (tcuActive \u0026\u0026 tcu) {\n const ecu8_12 = ecu.substring(16, 24); \/\/ 4 bytes = 8 hex chars\n const tcu8_12 = tcu.substring(16, 24);\n if (ecu8_12 !== tcu8_12) {\n issues.push('ECU[8:12] !== TCU[8:12]');\n }\n }\n \n \/\/ TCU and ELV overlap: TCU[0:4] === ELV[0:4] AND TCU[4:8] === ELV[4:8]\n if (tcuActive \u0026\u0026 elvActive \u0026\u0026 tcu \u0026\u0026 elv) {\n const tcu0_4 = tcu.substring(0, 8);\n const elv0_4 = elv.substring(0, 8);\n const tcu4_8 = tcu.substring(8, 16);\n const elv4_8 = elv.substring(8, 16);\n \n if (tcu0_4 !== elv0_4) {\n issues.push('TCU[0:4] !== ELV[0:4]');\n }\n if (tcu4_8 !== elv4_8) {\n issues.push('TCU[4:8] !== ELV[4:8]');\n }\n }\n \n if (issues.length \u003e 0) {\n return 'Warning: modules don\\'t appear aligned — computing anyway';\n }\n return null;\n }\n\n function reverseCalculate(syncHex, immoHex, tcuActive, elvActive) {\n const a = hexToBytes(immoHex);\n const output = hexToBytes(syncHex);\n const block1 = output.slice(0, 16);\n const block2 = output.slice(16, 32);\n const p1 = aesDecrypt(a, (a[0] === 0) ? applyW(block1) : block1);\n const p2 = aesDecrypt(a, (a[0] === 0) ? applyW(block2) : block2);\n\n \/\/ b formula is always the same\n const b = new Uint8Array(16);\n b.set(p1.slice(0, 4), 0);\n b.set(p2.slice(4, 8), 4);\n b.set(p2.slice(8, 12), 8);\n b.set(p1.slice(12, 16), 12);\n\n \/\/ c formula — universal (same formula regardless of tcuActive)\n const c = new Uint8Array(16);\n c.set(p2.slice(0, 4), 0);\n c.set(p1.slice(4, 8), 4);\n c.set(p2.slice(8, 12), 8);\n c.set(p1.slice(12, 16), 12);\n\n \/\/ c[7] fix when nibbles differ\n if ((p1[4] \u003e\u003e 4) !== (p2[4] \u003e\u003e 4)) {\n c[7] = p1[7] ^ p1[4] ^ p2[4];\n }\n\n \/\/ elv (d) is only valid when elvActive\n const elv = elvActive ? bytesToHex(p1) : '(inferred - ELV not active)';\n\n return {\n ecu: bytesToHex(b),\n tcu: bytesToHex(c),\n elv: elv,\n p1: bytesToHex(p1),\n p2: bytesToHex(p2)\n };\n }\n\n document.getElementById('fwdTCUActive').addEventListener('change', (e) =\u003e {\n document.getElementById('fwdTCUField').classList.toggle('hidden', !e.target.checked);\n });\n\n document.getElementById('fwdELVActive').addEventListener('change', (e) =\u003e {\n document.getElementById('fwdELVField').classList.toggle('hidden', !e.target.checked);\n });\n\n document.getElementById('btnForward').addEventListener('click', () =\u003e {\n document.getElementById('btnForward').classList.add('active');\n document.getElementById('btnReverse').classList.remove('active');\n document.getElementById('forwardMode').classList.remove('hidden');\n document.getElementById('reverseMode').classList.add('hidden');\n document.getElementById('result').classList.add('hidden');\n document.getElementById('syncDownloadSection').classList.add('hidden');\n });\n\n document.getElementById('btnReverse').addEventListener('click', () =\u003e {\n document.getElementById('btnReverse').classList.add('active');\n document.getElementById('btnForward').classList.remove('active');\n document.getElementById('reverseMode').classList.remove('hidden');\n document.getElementById('forwardMode').classList.add('hidden');\n document.getElementById('result').classList.add('hidden');\n document.getElementById('syncDownloadSection').classList.add('hidden');\n });\n\n document.getElementById('btnCalcSync').addEventListener('click', () =\u003e {\n const immo = document.getElementById('fwdImmo').value.trim();\n const ecu = document.getElementById('fwdECU').value.trim();\n const tcu = document.getElementById('fwdTCU').value.trim();\n const elv = document.getElementById('fwdELV').value.trim();\n const tcuActive = document.getElementById('fwdTCUActive').checked;\n const elvActive = document.getElementById('fwdELVActive').checked;\n \n const resultDiv = document.getElementById('result');\n\n if (!immo || !ecu) {\n resultDiv.innerHTML = '\u003cdiv class=\"result-title\"\u003eError\u003c\/div\u003eIMMO and ECU are required';\n resultDiv.classList.add('result-error');\n resultDiv.classList.remove('hidden');\n return;\n }\n\n if (immo.length !== 32 || ecu.length !== 32) {\n resultDiv.innerHTML = '\u003cdiv class=\"result-title\"\u003eError\u003c\/div\u003eIMMO and ECU must be 32 hex characters (16 bytes)';\n resultDiv.classList.add('result-error');\n resultDiv.classList.remove('hidden');\n return;\n }\n\n if (tcuActive \u0026\u0026 (!tcu || tcu.length !== 32)) {\n resultDiv.innerHTML = '\u003cdiv class=\"result-title\"\u003eError\u003c\/div\u003eTCU is active but TCU value is missing or invalid';\n resultDiv.classList.add('result-error');\n resultDiv.classList.remove('hidden');\n return;\n }\n\n if (elvActive \u0026\u0026 (!elv || elv.length !== 32)) {\n resultDiv.innerHTML = '\u003cdiv class=\"result-title\"\u003eError\u003c\/div\u003eELV is active but ELV value is missing or invalid';\n resultDiv.classList.add('result-error');\n resultDiv.classList.remove('hidden');\n return;\n }\n\n \/\/ Check overlap warnings in forward mode\n const overlapWarning = checkOverlapWarnings(ecu, tcu, elv, tcuActive, elvActive);\n if (overlapWarning) {\n alert(overlapWarning);\n }\n\n try {\n const sync = calculateSync(immo, ecu, tcu, elv, tcuActive, elvActive);\n document.getElementById('syncDisplay').textContent = sync;\n document.getElementById('syncDownloadSection').classList.remove('hidden');\n document.getElementById('result').classList.add('hidden');\n window.lastSyncBytes = hexToBytes(sync);\n } catch (e) {\n resultDiv.innerHTML = '\u003cdiv class=\"result-title\"\u003eError\u003c\/div\u003e' + e.message;\n resultDiv.classList.add('result-error');\n resultDiv.classList.remove('hidden');\n }\n });\n\n document.getElementById('btnDownloadSync').addEventListener('click', () =\u003e {\n if (window.lastSyncBytes) {\n const blob = new Blob([window.lastSyncBytes], { type: 'application\/octet-stream' });\n const url = URL.createObjectURL(blob);\n const a = document.createElement('a');\n a.href = url;\n a.download = 'sync.bin';\n a.click();\n URL.revokeObjectURL(url);\n }\n });\n\n document.getElementById('btnLoadSync').addEventListener('click', () =\u003e {\n document.getElementById('fileSync').click();\n });\n\n function loadImmoFile(inputId, buttonId, immoFieldId, vinFieldId) {\n const fileInput = document.getElementById(inputId);\n fileInput.click();\n fileInput.onchange = (e) =\u003e {\n const file = e.target.files[0];\n if (!file) return;\n if (file.size !== 189) {\n alert('Invalid file: must be exactly 189 bytes, got ' + file.size + ' bytes');\n fileInput.value = '';\n return;\n }\n const reader = new FileReader();\n reader.onload = (event) =\u003e {\n const bytes = new Uint8Array(event.target.result);\n \/\/ Parse VIN at offset 0x17-0x27 (17 bytes)\n const vinBytes = bytes.slice(0x17, 0x28);\n const vin = String.fromCharCode.apply(null, vinBytes);\n \/\/ Validate VIN is alphanumeric\n if (!\/^[A-Za-z0-9]+$\/.test(vin)) {\n alert('Invalid VIN: contains non-alphanumeric characters');\n document.getElementById(vinFieldId).closest('.field').classList.add('hidden');\n return;\n }\n \/\/ Parse IMMO key at offset 0x28-0x37 (16 bytes = 32 hex chars)\n const immoBytes = bytes.slice(0x28, 0x38);\n const immoHex = Array.from(immoBytes).map(b =\u003e b.toString(16).padStart(2, '0')).join('').toUpperCase();\n \/\/ Fill IMMO field\n document.getElementById(immoFieldId).value = immoHex;\n \/\/ Show VIN field\n const vinField = document.getElementById(vinFieldId);\n vinField.value = vin;\n vinField.closest('.field').classList.remove('hidden');\n };\n reader.readAsArrayBuffer(file);\n };\n }\n\n document.getElementById('btnLoadFwdImmo').addEventListener('click', () =\u003e {\n loadImmoFile('fileFwdImmo', 'btnLoadFwdImmo', 'fwdImmo', 'fwdVIN');\n });\n\n document.getElementById('btnLoadRevImmo').addEventListener('click', () =\u003e {\n loadImmoFile('fileRevImmo', 'btnLoadRevImmo', 'revImmo', 'revVIN');\n });\n\n document.getElementById('fileSync').addEventListener('change', (e) =\u003e {\n const file = e.target.files[0];\n if (file) {\n const reader = new FileReader();\n reader.onload = (event) =\u003e {\n const bytes = new Uint8Array(event.target.result);\n document.getElementById('revSync').value = bytesToHex(bytes);\n };\n reader.readAsArrayBuffer(file);\n }\n });\n\n document.getElementById('btnReverseCalc').addEventListener('click', () =\u003e {\n const sync = document.getElementById('revSync').value.trim();\n const immo = document.getElementById('revImmo').value.trim();\n const tcuActive = document.getElementById('revTCUActive').checked;\n const elvActive = document.getElementById('revELVActive').checked;\n const resultDiv = document.getElementById('result');\n\n if (!sync || !immo) {\n resultDiv.innerHTML = '\u003cdiv class=\"result-title\"\u003eError\u003c\/div\u003eSync and IMMO are required';\n resultDiv.classList.add('result-error');\n resultDiv.classList.remove('hidden');\n return;\n }\n\n if (sync.length !== 64) {\n resultDiv.innerHTML = '\u003cdiv class=\"result-title\"\u003eError\u003c\/div\u003eSync must be 64 hex characters (32 bytes)';\n resultDiv.classList.add('result-error');\n resultDiv.classList.remove('hidden');\n return;\n }\n\n if (immo.length !== 32) {\n resultDiv.innerHTML = '\u003cdiv class=\"result-title\"\u003eError\u003c\/div\u003eIMMO must be 32 hex characters (16 bytes)';\n resultDiv.classList.add('result-error');\n resultDiv.classList.remove('hidden');\n return;\n }\n\n try {\n const result = reverseCalculate(sync, immo, tcuActive, elvActive);\n resultDiv.innerHTML = `\n \u003cdiv class=\"result-title\"\u003eRecovered Values\u003c\/div\u003e\n \u003cdiv class=\"result-item\"\u003e\n \u003cdiv class=\"result-label\"\u003eECU\u003c\/div\u003e\n \u003cdiv class=\"result-value\"\u003e${result.ecu}\u003c\/div\u003e\n \u003c\/div\u003e\n \u003cdiv class=\"result-item\"\u003e\n \u003cdiv class=\"result-label\"\u003eTCU\u003c\/div\u003e\n \u003cdiv class=\"result-value\"\u003e${result.tcu}\u003c\/div\u003e\n \u003c\/div\u003e\n \u003cdiv class=\"result-item\"\u003e\n \u003cdiv class=\"result-label\"\u003eELV\u003c\/div\u003e\n \u003cdiv class=\"result-value\"\u003e${result.elv}\u003c\/div\u003e\n \u003c\/div\u003e\n `;\n resultDiv.classList.remove('result-error');\n resultDiv.classList.remove('hidden');\n } catch (e) {\n resultDiv.innerHTML = '\u003cdiv class=\"result-title\"\u003eError\u003c\/div\u003e' + e.message;\n resultDiv.classList.add('result-error');\n resultDiv.classList.remove('hidden');\n }\n });\n \u003c\/script\u003e\u003c\/p\u003e","brand":"KEY LIBRARY","offers":[{"title":"Default Title","offer_id":57216311492990,"sku":null,"price":0.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0569\/2751\/8813\/files\/VAGSYNCCALCULATOR_1.jpg?v=1775519596","url":"https:\/\/www.keylibrary.co.uk\/products\/vag-sync-calculator","provider":"Key Library","version":"1.0","type":"link"}