# Generate or verify a iCVV for a specific card
<a name="use-cases-issuers.generalfunctions.icvv"></a>

[iCVV](terminology.md#terms.icvv) uses the same algorithm as CVV/CVV2 but iCVV is embedded inside a chip card. Its service code is 999.

## Create the key
<a name="use-cases-issuers.generalfunctions.icvv.setup"></a>

```
$ aws payment-cryptography create-key --exportable --key-attributes KeyAlgorithm=TDES_2KEY,KeyUsage=TR31_C0_CARD_VERIFICATION_KEY,KeyClass=SYMMETRIC_KEY,KeyModesOfUse='{Generate=true,Verify=true}' --tags='[{"Key":"KEY_PURPOSE","Value":"ICVV"},{"Key":"CARD_BIN","Value":"12345678"}]'
```

The response echoes back the request parameters, including an ARN for subsequent calls as well as a Key Check Value (KCV).

```
{
               "Key": {
                   "KeyArn": "arn:aws:payment-cryptography:us-east-2:111122223333:key/c7dsi763r6s7lfp3",
                   "KeyAttributes": {
                       "KeyUsage": "TR31_C0_CARD_VERIFICATION_KEY",
                       "KeyClass": "SYMMETRIC_KEY",
                       "KeyAlgorithm": "TDES_2KEY",
                       "KeyModesOfUse": {
                           "Encrypt": false,
                           "Decrypt": false,
                           "Wrap": false,
                           "Unwrap": false,
                           "Generate": true,
                           "Sign": false,
                           "Verify": true,
                           "DeriveKey": false,
                           "NoRestrictions": false
                       }
                   },
                   "KeyCheckValue": "1201FB",
                   "KeyCheckValueAlgorithm": "ANSI_X9_24",
                   "Enabled": true,
                   "Exportable": true,
                   "KeyState": "CREATE_COMPLETE",
                   "KeyOrigin": "AWS_PAYMENT_CRYPTOGRAPHY",
                   "CreateTimestamp": "2023-06-05T06:41:46.648000-07:00",
                   "UsageStartTimestamp": "2023-06-05T06:41:46.626000-07:00"
               }
           }
```

Take note of the `KeyArn` that represents the key, for example *arn:aws:payment-cryptography:us-east-2:111122223333:key/c7dsi763r6s7lfp3*. You need that in the next step.

## Generate a iCVV
<a name="use-cases-issuers.generalfunctions.icvv.generate"></a>

**Example**  
In this example, we will generate a [iCVV](terminology.md#terms.icvv) for a given PAN with inputs of `PAN`,a service code(as defined by ISO/IEC 7813) of 999 and card expiration date.   
For all available parameters see [CardVerificationValue1](https://docs.aws.amazon.com/payment-cryptography/latest/DataAPIReference/API_CardVerificationValue1.html) in the API reference guide.   

```
$ aws payment-cryptography-data generate-card-validation-data --key-identifier arn:aws:payment-cryptography:us-east-2:111122223333:key/c7dsi763r6s7lfp3 --primary-account-number=171234567890123 --generation-attributes CardVerificationValue1='{CardExpiryDate=1127,ServiceCode=999}'
```

```
                     {
                         "KeyArn": "arn:aws:payment-cryptography:us-east-2:111122223333:key/c7dsi763r6s7lfp3",
                         "KeyCheckValue": "1201FB",
                         "ValidationData": "532"
                     }
```

## Validate iCVV
<a name="use-cases-issuers.generalfunctions.icvv.verify"></a>

**Example**  
For validation, the inputs are CVK, `PAN`, a service code of 999, card expiration date and the iCVV provided during the transaction to validate.   
For all available parameters see, [CardVerificationValue1](https://docs.aws.amazon.com/payment-cryptography/latest/DataAPIReference/API_CardVerificationValue1.html) in the API reference guide.   
iCVV is not a user entered value (like CVV2) but is typically embedded on an EMV/chip card. Consideration should be given to whether it should always validate when provided.

```
$ aws payment-cryptography-data verify-card-validation-data --key-identifier arn:aws:payment-cryptography:us-east-2:111122223333:key/c7dsi763r6s7lfp3 --primary-account-number=171234567890123 --verification-attributes CardVerificationValue1='{CardExpiryDate=1127,ServiceCode=999} --validation-data 532
```

```
{
                       "KeyArn": "arn:aws:payment-cryptography:us-east-2:111122223333:key/c7dsi763r6s7lfp3",
                       "KeyCheckValue": "1201FB",
                       "ValidationData": "532"
   }
```