3DS 回退
即使 3D Secure 2. 0 不可用或遇到問題，也能確保交易連續性。
Cardflo 的 3DS 回退機制會自動切換到 3DS 1. 0，防止原本會發生的拒絕交易。
這維持了交易流程並確保了商戶的收入。
- 類別
- 安全
- 功能數
- 10
- 適用於
- 所有方案
概覽
3DS fallback is a contingency logic used within the payment gateway or orchestration layer to manage authentication failures during the 3D Secure 2. 0 (3DS2) handshake.
While the industry has prioritised the adoption of 3DS2 to meet SCA requirements under PSD2, certain regional issuers or older banking infrastructures may not yet support the latest protocols.
If an initial 3DS2 request is met with a technical error, a timeout, or a response indicating the issuer is not enrolled, a fallback mechanism attempts to initiate 3DS1 (Legacy 3D Secure).
This process ensures that the transaction remains eligible for authentication rather than defaulting to a hard decline. By attempting the older protocol, merchants can still satisfy regulatory mandates and secure a liability shift, provided the issuer still maintains a legacy Access Control Server (ACS).
This secondary routing logic sits between the initial authentication request and the final authorisation call to the acquirer.
運作方式
Initial 3DS2 versioning attempt
The merchant initiates a transaction through the gateway, which first attempts to identify the appropriate 3DS2 version supported by the issuer. The system analyses the BIN and the Directory Server response to determine if the newer, frictionless protocol is available for the specific cardholder.
Error or non-participation detection
If the Directory Server returns a status indicating that the issuer has not implemented 3DS2, or if a technical error occurs during the versioning exchange, the system identifies this as a potential failure point that would lead to a transaction refusal if left unaddressed.
Automatic 3DS1 message construction
The fallback engine immediately reformats the authentication request into a 3DS1-compliant message. This includes generating the necessary redirect URLs for the legacy browser-based challenge, ensuring the customer is transitioned to the issuer authentication page without a hard abandonment of the payment session.
Fallback authentication execution
The cardholder completes the legacy authentication process, typically involving a static password or an SMS-based code. Once the issuer verifies the identity, they provide an authentication value, such as a CAVV or AAV, which is necessary for the subsequent authorisation request to the acquirer.
Authorisation with legacy proof
The transaction proceeds to the acquirer with the 3DS1 authentication data. If validated, the merchant usually retains the benefit of the liability shift, protecting the business from fraud-related chargebacks despite the transaction not being processed via the primary 3DS2 protocol.
為何重要
Prevention of technical declines
Relying solely on 3DS2 can lead to unnecessary payment failures when interacting with issuers in developing markets or those with delayed infrastructure updates.
Fallback logic ensures that a lack of modern protocol support does not automatically translate into a lost sale, maintaining the merchant's conversion rate across diverse cardholder bases.
Regulatory compliance and security
In jurisdictions governed by PSD2, authentication is a legal requirement for most remote transactions.
Falling back to 3DS1 allows merchants to remain compliant with Strong Customer Authentication (SCA) rules when the preferred 3DS2 path is unavailable, avoiding the risk of regulator-enforced transaction blocks or fines for non-compliance.
Protection against fraud liability
A primary advantage of 3D Secure is the shift of liability from the merchant to the issuer for fraudulent disputes.
Without a fallback mechanism, a merchant might be forced to process a transaction without any authentication, exposing themselves to financial loss if the transaction is later disputed as unauthorised.
應用案例
Cross-border trade
Merchants selling to customers in regions where 3DS2 adoption lags behind Europe or North America use fallback to maintain successful authentication rates.
Legacy issuer support
Retailers with a high volume of transactions from small regional banks or credit unions that still operate on legacy 3DS1 infrastructure.
High-risk transaction security
Businesses in high-risk sectors use fallback to ensure every possible authentication path is tried, maximising the chances of securing a liability shift.
Platform and marketplace stability
Marketplaces with diverse sub-merchants use fallback to ensure that varied card types and issuer responses do not disrupt the aggregate checkout experience.
數據概覽
Typical authentication success rates when fallback is enabled, as it captures transactions from issuers lacking modern protocol support.
The estimated decrease in technical declines observed by merchants when implementing automated versioning and fallback logic.
The standard processing overhead for the gateway to switch protocols, excluding the time taken for the cardholder to interact with the challenge.
相關術語
Talk to our team about a live rollout on your acquiring stack.
What you get with 3DS 回退
- 自動檢測 3DS2 故障或不支持的環境
- 無縫重定向到 3DS1 以實現不間斷的身份驗證
- 在不同場景下保持符合 SCA 要求
- 減少因 3DS 版本不兼容引起的技術拒絕
- 確保與各種發卡行和收單方系統的廣泛兼容性
- 防止支付失敗，最大限度地減少客戶挫敗感
- Analyses Directory Server responses to determine the highest available protocol version.
- Reduces the volume of hard declines caused by issuer non-participation in 3DS2.
- Assists in global expansion by supporting older bank technology in emerging markets.
- Minimises cart abandonment by providing an alternative authentication route during system outages.
A short scoping call, then a written plan for your MIDs.
Questions about 3DS 回退
什麼是 3DS 回退？
3DS 回退是一種機制，如果交易無法使用 3D Secure 2. 0 處理，系統會自動恢復使用 3D Secure 1.
0。 這確保了交易仍然可以進行身份驗證和完成，防止交易被拒絕。
為什麼 3DS 回退很重要？
3DS 回退對於保持高授權率至關重要，尤其是在過渡到 3DS2 期間。 它能緩解發卡行或客戶設備可能無法完全支持 3DS2 的問題，確保交易仍能安全合規地處理。
3DS 回退會影響安全性嗎？
雖然 3DS1 提供了不同的用戶體驗，但它仍然提供了一層安全性並有助於滿足強客戶身份驗證 (SCA) 的監管要求。 回退機制確保在需要時始終應用安全身份驗證方法。
How does the system decide when to trigger a fallback?
The fallback is triggered based on the response from the Scheme Directory Server or the Issuer Access Control Server.
Common triggers include a 'Status N' (Not Enrolled) response for 3DS2, a technical error code indicating the server is down, or a timeout where the 3DS2 versioning request fails to receive a response within a set timeframe (often 2-5 seconds).
Can I disable 3DS fallback for specific regions or MCCs?
Yes, payment orchestration settings usually allow for granular control.
A merchant might choose to disable fallback for regions where 3DS1 is fully decommissioned or for specific Merchant Category Codes (MCCs) where the friction of a legacy redirect is deemed too high relative to the transaction value.
However, for most European merchants, keeping it enabled is standard practice to maximise authorisation success.
What happens if both 3DS2 and 3DS1 fail?
If both protocols fail, the transaction will typically be sent to the issuer as 'unauthenticated'.
Depending on the merchant's risk settings and the regional regulations (like SCA), the transaction may be declined by the gateway before reaching the acquirer, or it may be passed through to the issuer who will likely decline it with a 'soft decline' code, requesting authentication.
Are there additional scheme fees associated with 3DS fallback?
Scheme fees for 3D Secure are generally applied per authentication attempt. While there is usually no specific 'fallback fee', the merchant will remain responsible for the standard 3DS inquiry fees.
Some acquirers may have different pricing tiers for 3DS2 versus 3DS1, so it is advisable to check the interchange-plus or blended pricing schedule for any variations in processing costs.