# リスク評価

ダッシュボードと API で Stripe Radar リスク評価にアクセスします。

Stripe Radar は、支払いを監視し不審請求の申請からビジネスを保護する優れた能力を提供します。しかし、後から不審請求が申請されたり、不正利用であることが判明する支払いが存在するため、支払いを受け付けるかどうかを選択する[最終責任](https://stripe.com/us/legal#processing-transactions-disputes)はお客様にあります。

Stripe Radar includes an adaptive [AI model](https://stripe.com/radar/guide) that uses a risk score to evaluate the risk level for each payment in real time. The model uses hundreds of signals about each payment and data across our network of businesses to predict whether a payment is likely to be fraudulent. It learns from new customer purchase patterns and transaction features, and incorporates feedback from you whenever payments are marked as fraudulent.

Risk settings and the risk controls for fraudulent disputes and early fraud warnings don’t use this AI model. They use more specialized models that can balance the tradeoffs between authorization and fraud.

> Stripe を利用しているビジネスが、カード、SEPA Direct Debit アカウント、または ACH アカウントを確認した場合、Stripe は過去にその決済手段の支払いを処理した可能性があります。
> 
> - カードを確認したことがある確率は 92%
- SEPA アカウントを確認したことがある確率は 82%
- ACH アカウントを確認したことがある確率は 71%

## Radar を使用する状況

Radar evaluates risk and runs rules for three Stripe API objects: [Charges](https://docs.stripe.com/api/charges.md), [PaymentIntents](https://docs.stripe.com/api/payment_intents.md) and [SetupIntents](https://docs.stripe.com/api/setup_intents.md). Stripe designed the Radar rules to take four actions:

- 3DS 認証をリクエストする
- オブジェクトの作成を許可する
- オブジェクトの作成をブロックする
- Review the creation of a charge

以下のテーブルは、各タイプの API オブジェクトに対して Radar がどのルールを実行するかを示したものです。

| 取引タイプ         | 3DS のリクエスト    | Allow and Block | 審査            |
| ------------- | ------------- | --------------- | ------------- |
| Charge        | - Unsupported | ✓ Supported     | ✓ Supported   |
| PaymentIntent | ✓ Supported   | ✓ Supported     | ✓ Supported   |
| SetupIntent   | ✓ Supported   | ✓ Supported     | - Unsupported |

If you use card payments, you can enable Radar for SetupIntents in your [Radar settings](https://dashboard.stripe.com/test/radar/settings).

### Use Radar with Stripe Checkout or Stripe Billing

This information also applies to payments created using Stripe Checkout and Stripe Billing. To provide a seamless flow for your *subscription* (A Subscription represents the product details associated with the plan that your customer subscribes to. Allows you to charge the customer on a recurring basis) customers, the Radar fraud models only score the initial payment of a recurring Stripe Billing subscription, but evaluate rules for all payments.

## リスクの結果

With Stripe Radar for Fraud Teams, each payment also includes a risk score that ranges from 0–99 to indicate the risk level on a more granular level. By default, a score of 65 or above indicates elevated risk, while a score of 75 or above indicates high risk.

The Stripe AI model evaluates the likelihood that a payment is fraudulent, and provides an assessment of one of the following values:

- [高リスク](https://docs.stripe.com/radar/risk-evaluation.md#high-risk)
- [比較的高いリスク](https://docs.stripe.com/radar/risk-evaluation.md#elevated-risk)
- [通常リスク](https://docs.stripe.com/radar/risk-evaluation.md#normal-risk)
- [未評価](https://docs.stripe.com/radar/risk-evaluation.md#not-evaluated)
- [不明なリスク](https://docs.stripe.com/radar/risk-evaluation.md#unknown-risk)

各支払いには、リスク評価の「結果」が含まれます。

Radar for Fraud Teams lets you see a [risk insights](https://docs.stripe.com/radar/reviews/risk-insights.md) section on the payment page that provides more details about why we assigned a payment a particular risk level and score.

If a financial institution (such as a card issuer or bank) [declines](https://docs.stripe.com/declines.md) a payment, Stripe also includes any information we receive from them as part of the outcome. You can see the outcome for each payment in the [Dashboard](https://dashboard.stripe.com/), or through the API in the [Outcome](https://docs.stripe.com/api.md#charge_object-outcome) attribute of the [Charge](https://docs.stripe.com/api.md#charge_object) object.

### 高リスクの支払い

Stripe は、不正利用である可能性が高いと判断した場合、支払いを高リスクとして報告します。このリスクレベルの支払いは、デフォルトで[ブロック](https://docs.stripe.com/radar/rules.md#built-in-rules)されます。

高リスクの支払いの `Charge` オブジェクトでは、`risk_level` は `highest` に設定されます。

```json
...
"outcome":
{
  "network_status": "not_sent_to_network",
  "reason": "highest_risk_level",
  "risk_level": "highest",
  "risk_score": 92, // Provided only with Stripe Radar for Fraud Teams
  "seller_message": "Stripe blocked this charge as too risky.",
  "type": "blocked",
}
...
```

If Stripe Radar blocks a payment that you know is legitimate, you can remove the block by viewing the payment in the Dashboard and clicking **Add to allow list**. Adding a payment to the allow list doesn’t retry the payment, but it does prevent Stripe Radar from blocking future payment attempts with that payment method or email address.

> If you don’t see **Add to allow list**, you can [contact us](https://support.stripe.com/email) to add this feature to your Radar account.

### 比較的高いリスクの支払い

Elevated risk payments have an increased chance of being fraudulent. Stripe Radar allows payments of this risk level by default. Stripe Radar for Fraud Teams automatically places elevated risk payments into your [review](https://docs.stripe.com/radar/reviews.md) queue so you can look at them more closely.

比較的高いリスクの支払いの `Charge` オブジェクトでは、`risk_level` は `elevated` に設定されます。

```json
...
"outcome": {
  "network_status": "approved_by_network",
  "reason": "elevated_risk_level",
  "risk_level": "elevated",
  "risk_score": 56, // Provided only with Stripe Radar for Fraud Teams
  "seller_message": "Stripe evaluated this charge as having elevated risk, and placed it in your manual review queue.",
  "type": "manual_review"
}
...
```

### 通常リスクの支払い

Payments with a normal risk evaluation have fewer characteristics that indicate fraud than payments with elevated or high risk levels. However, we recommend that you continue to be vigilant when fulfilling these orders. Payments that have normal risk can still turn out to be fraudulent, and there are other possible [types of fraud](https://docs.stripe.com/disputes/prevention/identifying-fraud.md) that can occur later in the order process.

通常リスクで支払いに成功した `Charge` オブジェクトでは、`risk_level` は `normal` に設定されます。

```json
...
"outcome":
{
  "network_status": "approved_by_network",
  "reason": null,
  "seller_message": "The charge was authorized.",
  "risk_level": "normal",
  "risk_score": 23, // Provided only with Stripe Radar for Fraud Teams
  "type": "authorized",
}
...
```

### 未評価

Radar assesses the risk level for card, ACH, and SEPA Direct Debit payments, and sets the risk level to `not_assessed` for:

- All other non-card payments
- Card-based payments predating the public assignment of risk levels
- Payments where the business opts out of Radar fraud risk assessment

リスク未評価の支払いの `Charge` オブジェクトでは、`risk_level` は `not_assessed` に設定されます。

```json
...
"outcome": {
  "network_status": "approved_by_network",
  "reason": "not_assessed_risk_level",
  "risk_level": "not_assessed",
  "seller_message": "Your business has opted out of Radar fraud risk assessments.",
  "type": "authorized"
}
...
```

### 不明なリスクの支払い

In unusual cases, an error might cause risk evaluation to fail. If this happens, Stripe reports the payment as having unknown risk.

リスクが不明な支払いの `Charge` オブジェクトでは、`risk_level` は `unknown` に設定されます。

```json
...
"outcome": {
  "network_status": "approved_by_network",
  "reason": "unknown_risk_level",
  "risk_level": "unknown",
  "seller_message": "Something went wrong while evaluating this payment. Our engineers have been notified and we’ll look into this as soon as possible.",
  "type": "authorized"
}
...
```

## Search for a specific risk level in the Dashboard 

You can search for payments with a specific risk level using the **risk\_level** search term and the desired risk level. For example, a search for [risk_level:highest](https://dashboard.stripe.com/test/search?query=risk_level%3Ahighest) returns a list of all payments with a high risk level. A search for [risk_level:elevated](https://dashboard.stripe.com/test/search?query=risk_level%3Aelevated) returns a list of all payments with an elevated risk level.

## Provide feedback on risk evaluations 

While we use information across our network to evaluate a payment, you might have additional information about a payment as a result of a customer interaction. Our AI model responds to feedback you share with us, and you can help improve our fraud detection algorithms and the accuracy of our risk evaluations by [refunding](https://docs.stripe.com/refunds.md) and reporting payments that you believe are fraudulent.

To refund a payment and mark it as fraudulent, do the following:

1. View the payment in the Dashboard.
1. **返金**をクリックします。
1. **理由** として **不正** を選択します。
1. 短い説明を入力します

または、API を使用して[返金を作成](https://docs.stripe.com/api.md#create_refund)する際に、`reason` の値に `fraudulent` を使用して支払いが不正利用であることを示すこともできます。これにより、その支払いに関連付けられたメールアドレスとカードフィンガープリントが、デフォルトのメールアドレスとカードフィンガープリント[ブロックリスト](https://docs.stripe.com/radar/lists.md#default-lists)に追加されます。

#### Ruby

```ruby

# Don't put any keys in code. See https://docs.stripe.com/keys-best-practices.
# Find your keys at https://dashboard.stripe.com/apikeys.
Stripe.api_key = '<<YOUR_SECRET_KEY>>'

# If you haven't refunded the charge, you can do so and let Stripe
# know it was fraudulent in one step.
Stripe::Refund.create({
  charge: '{{CHARGE_ID}}',
  reason: 'fraudulent',
})

# If you already refunded the charge (without specifying the
# 'fraudulent' reason), you can still let us know it was fraudulent.
Stripe::Charge.update(
  '{{CHARGE_ID}}',
  {
    fraud_details: {
      user_report: 'fraudulent',
    },
  }
)
```

For a small subset of payments, Stripe modifies the reported risk score so we can measure the performance of our models and obtain data for subsequent model development. This allows us to make sure key metrics, such as false positive rate and recall, remain within desirable ranges, and that model performance continues to improve.

You can opt out of using the Stripe Radar API model by [contacting support](https://stripe.com/contact).