MLE Decryption Failing

[coleyb]

I'll first start by saying I am not sure if this on the CyberSource Test API side or this gem. I reached out to their support but it's getting no where. We recently ran into an issue where MLE decryption stopped working when no changes or deployments were made on our side. We are on version 0.0.82 of this gem. We are hitting apitest.cybersource.com and attempting to call.

      payment_instance = CyberSource::PaymentsApi.new(api_client, config)

      response, status_code = payment_instance.create_payment(request_obj)

The error returned is CyberSource::ApiError Exception: Failure when receiving data from the peer. It works fine when enableResponseMleGlobally is set to false. We already tried swapping out our certs to no avail.

Any help would be appreciated! Below is our log output as well:

[2026-03-11 11:11:57] INFO   (MerchantConfig): START> =======================================
[2026-03-11 11:11:57] INFO   (MerchantConfig): Entered value for Key File Path : /path/to/resource/StagingCybersourceRequestMLE.p12
[2026-03-11 11:11:57] INFO   (MerchantConfig): Merchant Configuration:
{
  "runEnvironment"                           => "apitest.cybersource.com",
  "timeout"                                  => 10000,
  "authenticationType"                       => "JWT",
  "jsonFilePath"                             => "/path/to/resource/request.json",
  "keysDirectory"                            => "/path/to/resource",
  "keyFilename"                              => "StagingCybersourceRequestMLE",
  "logConfiguration"                         => {
    "enableLog"     => true,
    "loggingLevel"  => "DEBUG",
    "logDirectory"  => "log",
    "logFilename"   => "cybs",
    "maxLogSize"    => 10485760,
    "maxLogFiles"   => 5,
    "enableMasking" => true
  },
  "enableRequestMLEForOptionalApisGlobally"  => true,
  "requestMleKeyAlias"                       => "CyberSource_SJC_US",
  "enableResponseMleGlobally"                => true,
  "responseMlePrivateKeyFilePath"            => "/path/to/resource/StagingCybersourceResponseMLE.p12",
  "responseMlePrivateKeyFilePassword"        => "[REDACTED]",
  "responseMleKID"                           => "[REDACTED]"
}

[2026-03-11 11:12:04] INFO   (MLEUtility): Encrypting request payload
[2026-03-11 11:12:04] DEBUG  (MLEUtility): LOG_REQUEST_BEFORE_MLE:
{
  "clientReferenceInformation": {
    "code": "[REDACTED]",
    "partner": { "developerId": "[REDACTED]" }
  },
  "processingInformation": {
    "capture": true,
    "commerceIndicator": "internet"
  },
  "paymentInformation": {
    "customer": { "id": "[REDACTED]" }
  },
  "orderInformation": {
    "amountDetails": {
      "totalAmount": "5.17",
      "currency": "USD"
    }
  }
}
[2026-03-11 11:12:04] DEBUG  (MLEUtility): LOG_REQUEST_AFTER_MLE: { "encryptedRequest": "[ENCRYPTED_PAYLOAD]" }
[2026-03-11 11:12:04] INFO   (Authorization): Authentication Type: JWT
[2026-03-11 11:12:04] DEBUG  (MLEUtility): Validating responseMleKID for JWT token generation
[2026-03-11 11:12:04] DEBUG  (MLEUtility): P12/PFX file detected, checking if it is a CyberSource certificate
[2026-03-11 11:12:04] DEBUG  (MLEUtility): Successfully auto-extracted responseMleKID from CyberSource P12 certificate

[2026-03-11 11:16:05] INFO   (MLEUtility): Encrypting request payload
[2026-03-11 11:16:05] DEBUG  (MLEUtility): LOG_REQUEST_BEFORE_MLE:
{
  "clientReferenceInformation": {
    "code": "[REDACTED]",
    "partner": { "developerId": "[REDACTED]" }
  },
  "processingInformation": {
    "capture": true,
    "commerceIndicator": "internet"
  },
  "paymentInformation": {
    "customer": { "id": "[REDACTED]" }
  },
  "orderInformation": {
    "amountDetails": {
      "totalAmount": "5.17",
      "currency": "USD"
    }
  }
}
[2026-03-11 11:16:05] DEBUG  (MLEUtility): LOG_REQUEST_AFTER_MLE: { "encryptedRequest": "[ENCRYPTED_PAYLOAD]" }
[2026-03-11 11:16:05] INFO   (Authorization): Authentication Type: JWT
[2026-03-11 11:16:05] DEBUG  (MLEUtility): Validating responseMleKID for JWT token generation
[2026-03-11 11:16:05] DEBUG  (MLEUtility): P12/PFX file detected, checking if it is a CyberSource certificate
[2026-03-11 11:16:05] DEBUG  (MLEUtility): Successfully auto-extracted responseMleKID from CyberSource P12 certificate

[gaubansa]

Hi @coleyb

Thank you for reporting this issue.

This is a known bug with the enableResponseMleGlobally configuration flag with the Payments API, and our team is actively working on a fix.

Workaround: In the meantime, please use the mapToControlMLEonAPI flag to enable Response MLE on a per-API basis instead of the global flag. This allows you to configure MLE at the individual API level and is unaffected by the current issue.

For detailed configuration instructions and usage examples, please refer to the MLE.md documentation in the repository.

We will update this issue once the fix has been deployed. We apologize for the inconvenience and appreciate your patience.