{
  "name": "Validate a TOTP Code",
  "nodes": [
    {
      "id": "validate-a-totp-code-0",
      "name": "When clicking ‘Test workflow’",
      "type": "n8n-nodes-base.manualTrigger",
      "position": [
        480,
        680
      ],
      "parameters": {},
      "typeVersion": 1
    },
    {
      "id": "validate-a-totp-code-1",
      "name": "TOTP VALIDATION",
      "type": "n8n-nodes-base.code",
      "position": [
        920,
        680
      ],
      "parameters": {
        "language": "python",
        "pythonCode": "import hmac\nimport hashlib\nimport time\nimport base64\n\ndef base32_decode(key):\n    \"\"\"Decodes a base32 key into bytes\"\"\"\n    key += '=' * (-len(key) % 8)  # Add necessary '=' for valid length\n    return base64.b32decode(key.upper(), casefold=True)\n\ndef generate_totp(secret, interval=30, digits=6):\n    \"\"\"Generates a TOTP code based on a secret key\"\"\"\n    interval_count = int(time.time() // interval)\n    interval_bytes = interval_count.to_bytes(8, byteorder='big')\n\n    hmac_hash = hmac.new(secret, interval_bytes, hashlib.sha1).digest()\n    \n    offset = hmac_hash[-1] & 0x0F\n    binary_code = ((hmac_hash[offset] & 0x7F) << 24 |\n                   (hmac_hash[offset + 1] & 0xFF) << 16 |\n                   (hmac_hash[offset + 2] & 0xFF) << 8 |\n                   (hmac_hash[offset + 3] & 0xFF))\n    \n    otp_code = binary_code % (10 ** digits)\n    \n    # Format with leading zeros if necessary\n    otp_code_str = str(otp_code).zfill(digits)\n    \n    return otp_code_str\n\ndef verify_totp(secret, code, interval=30, digits=6):\n    \"\"\"Checks whether the TOTP code is valid\"\"\"\n    secret_bytes = base32_decode(secret)\n    generated_code = generate_totp(secret_bytes, interval, digits)\n    \n    return generated_code == code\n\n# Example of use\nsecret = _input.item.json.totp_secret_example  # Secret key base32 (example)\ncode =  _input.item.json.code_to_verify_example # Code to check (example)\n\n# Return 1 if code is valid. Return 0 if invalid\nif verify_totp(secret, code):\n    return [{\"status\": 1}]\nelse:\n    return [{\"status\": 0}]"
      },
      "typeVersion": 2
    },
    {
      "id": "validate-a-totp-code-2",
      "name": "IF CODE IS VALID",
      "type": "n8n-nodes-base.if",
      "position": [
        1140,
        680
      ],
      "parameters": {
        "options": {},
        "conditions": {
          "options": {
            "leftValue": "",
            "caseSensitive": true,
            "typeValidation": "strict"
          },
          "combinator": "and",
          "conditions": [
            {
              "id": "470cf368-daee-4136-b907-a3539765871d",
              "operator": {
                "type": "number",
                "operation": "equals"
              },
              "leftValue": "={{ $json.status }}",
              "rightValue": 1
            }
          ]
        }
      },
      "typeVersion": 2.1
    },
    {
      "id": "validate-a-totp-code-3",
      "name": "EXAMPLE FIELDS",
      "type": "n8n-nodes-base.set",
      "position": [
        700,
        680
      ],
      "parameters": {
        "options": {},
        "assignments": {
          "assignments": [
            {
              "id": "03a66bf9-1bf4-44c0-92e0-edd45929e467",
              "name": "code_to_verify_example",
              "type": "string",
              "value": "000000"
            },
            {
              "id": "7bb18b0a-1851-4f27-a91f-5f93b663cfd0",
              "name": "totp_secret_example",
              "type": "string",
              "value": "YOUR_BASE32_SECRET"
            }
          ]
        }
      },
      "typeVersion": 3.4
    }
  ],
  "active": false,
  "pinData": {},
  "settings": {
    "executionOrder": "v1"
  },
  "connections": {
    "EXAMPLE FIELDS": {
      "main": [
        [
          {
            "node": "TOTP VALIDATION",
            "type": "main",
            "index": 0
          }
        ]
      ]
    },
    "TOTP VALIDATION": {
      "main": [
        [
          {
            "node": "IF CODE IS VALID",
            "type": "main",
            "index": 0
          }
        ]
      ]
    },
    "When clicking ‘Test workflow’": {
      "main": [
        [
          {
            "node": "EXAMPLE FIELDS",
            "type": "main",
            "index": 0
          }
        ]
      ]
    }
  }
}