Show A card security code (CSC; also known as CVC, CVV, or several other names) is a series of numbers that, in addition to the bank card number, is printed (not embossed) on a card. The CSC is used as a security feature for card not present transactions, where a personal identification number (PIN) cannot be manually entered by the cardholder (as they would during point-of-sale or card present transactions). It was instituted to reduce the incidence of credit card fraud. These codes are in slightly different places for different card issuers. The CSC for Visa, Mastercard, and Discover credit cards is a three-digit number on the back of the card, to the right of the signature box. The CSC for American Express is a four-digit code on the front of the card above the account number. See the figures to the right for examples. CSC was originally developed in the UK as an eleven-character alphanumeric code by Equifax employee Michael Stone in 1995. After testing with the Littlewoods Home Shopping group and NatWest bank, the concept was adopted by the UK Association for Payment Clearing Services (APACS) and streamlined to the three-digit code known today. Mastercard started issuing CVC2 numbers in 1997 and Visa in the United States issued them by 2001. American Express started to use the CSC in 1999, in response to growing Internet transactions and card member complaints of spending interruptions when the security of a card has been brought into question. Contactless card and chip cards may electronically generate their own code, such as iCVV or a dynamic CVV. NamingThe codes have different names:
TypesThere are several types of security codes and PVV (all generated from DES key in the bank in HSM modules using PAN, expiration date and service code):
LocationThe card security code is typically the last three or four digits printed, not embossed like the card number, on the signature strip on the back of the card. On American Express cards, however, the card security code is the four digits printed (not embossed) on the front towards the right. The card security code is not encoded on the magnetic stripe but is printed flat.
GenerationThe CSC for each card (form 1 and 2) is generated by the card issuer when the card is issued. It is calculated by encrypting the bank card number and expiration date (two fields printed on the card) with encryption keys known only to the card issuer, and decimalising the result (in a similar manner to a hash function).[8][9][10] Benefits and limitations
As a security measure, merchants who require the CVV2 for "card not present" transactions are required by the card issuer not to store the CVV2 once the individual transaction is authorized.[11] This way, if a database of transactions is compromised, the CVV2 is not present and the stolen card numbers are less useful. Virtual terminals and payment gateways do not store the CVV2 code; therefore, employees and customer service representatives with access to these web-based payment interfaces, who otherwise have access to complete card numbers, expiration dates, and other information, still lack the CVV2 code. The Payment Card Industry Data Security Standard (PCI DSS) also prohibits the storage of CSC (and other sensitive authorisation data) post transaction authorisation. This applies globally to anyone who stores, processes or transmits card holder data.[12] Since the CSC is not contained on the magnetic stripe of the card, it is not typically included in the transaction when the card is used face to face at a merchant. However, some merchants in North America, such as Sears and Staples, require the code. For American Express cards, this has been an invariable practice (for "card not present" transactions) in European Union (EU) countries like Ireland and the United Kingdom since the start of 2005. This provides a level of protection to the bank/cardholder, in that a fraudulent merchant or employee cannot simply capture the magnetic stripe details of a card and use them later for "card not present" purchases over the phone, mail order or Internet. To do this, a merchant or its employee would also have to note the CVV2 visually and record it, which is more likely to arouse the cardholder's suspicion. Supplying the CSC code in a transaction is intended to verify that the customer has the card in their possession. Knowledge of the code proves that the customer has seen the card, or has seen a record made by somebody who saw the card. Limitations include:
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Page 23-D Secure is a protocol designed to be an additional security layer for online credit and debit card transactions. The name refers to the "three domains" which interact using the protocol: the merchant/acquirer domain, the issuer domain, and the interoperability domain.[1] Originally developed in the autumn of 1999 by Celo Communications AB (later Gemplus, Gemalto and now Thales Group) for Visa Inc. in a project named "p42" ("p" from Pole vault as the project was a big challenge and "42" as the answer from the book The Hitchhiker's Guide to the Galaxy). A new updated version was developed by Gemplus between 2000-2001. In 2001 Arcot Systems (now CA Technologies) and Visa Inc.[2] with the intention of improving the security of Internet payments, and offered to customers under the Verified by Visa brand (later rebranded as Visa Secure). Services based on the protocol have also been adopted by Mastercard as SecureCode, by Discover as ProtectBuy,[3] by JCB International as J/Secure, and by American Express as American Express SafeKey.[4] Later revisions of the protocol have been produced by EMVCo under the name EMV 3-D Secure. Version 2 of the protocol was published in 2016 with the aim of complying with new EU authentication requirements and resolving some of the short-comings of the original protocol.[5] Analysis of the first version of the protocol by academia has shown it to have many security issues that affect the consumer, including a greater surface area for phishing and a shift of liability in the case of fraudulent payments.[6] Description and basic aspectsThe basic concept of the protocol is to tie the financial authorization process with online authentication. This additional security authentication is based on a three-domain model (hence the "3-D" in the name). The three domains are:
The protocol uses XML messages sent over SSL connections with client authentication[7] (this ensures the authenticity of both peers, the server and the client, using digital certificates). A transaction using Verified-by-Visa or SecureCode will initiate a redirection to the website of the card issuer to authorize the transaction. Each issuer could use any kind of authentication method (the protocol does not cover this) but typically, a password tied to the card is entered when making online purchases. The Verified-by-Visa protocol recommends the card issuer's verification page to load in an inline frame session. In this way, the card issuer's systems can be held responsible for most security breaches. Today it is easy to send a one-time password as part of an SMS text message to users' mobile phones and emails for authentication, at least during enrollment and for forgotten passwords. The main difference between Visa and Mastercard implementations lies in the method to generate the UCAF (Universal Cardholder Authentication Field): Mastercard uses AAV (Accountholder Authentication Value) and Visa uses CAVV (Cardholder Authentication Verification Value).[clarification needed] 3-D Secure FlowACS providersIn the 3-D Secure protocol, the ACS (access control server) is on the card issuer side. Currently, most card issuers outsource ACS to a third party. Commonly, the buyer's web browser shows the domain name of the ACS provider, rather than the card issuer's domain name; however, this is not required by the protocol. Dependent on the ACS provider, it is possible to specify a card issuer-owned domain name for use by the ACS. MPI providersEach 3-D Secure version 1 transaction involves two Internet request/response pairs: VEReq/VERes and PAReq/PARes.[7] Visa and Mastercard do not permit merchants to send requests directly to their servers. Merchants must instead use MPI (merchant plug-in) providers. MerchantsThe advantage for merchants is the reduction of "unauthorized transaction" chargebacks. One disadvantage for merchants is that they have to purchase a merchant plug-in (MPI) to connect to the Visa or Mastercard directory server. This is expensive[clarification needed] (setup fee, monthly fee, and per-transaction fee); at the same time, it represents additional revenue for MPI providers. Supporting 3-D Secure is complicated and, at times, creates transaction failures. Perhaps the biggest disadvantage for merchants is that many users view the additional authentication step as a nuisance or obstacle, which results in a substantial increase in transaction abandonment and lost revenue.[8] Buyers and credit card holdersIn most current implementations of 3-D Secure, the card issuer or its ACS provider prompts the buyer for a password that is known only to the card issuer or ACS provider and the buyer. Since the merchant does not know this password and is not responsible for capturing it, it can be used by the card issuer as evidence that the purchaser is indeed their cardholder. This is intended to help decrease risk in two ways:
3-D Secure does not strictly require the use of password authentication. It is said to be possible[9] to use it in conjunction with smart card readers, security tokens and the like. These types of devices might provide a better user experience for customers as they free the purchaser from having to use a secure password. Some issuers are now using such devices as part of the Chip Authentication Program or Dynamic Passcode Authentication schemes.[10] One significant disadvantage is that cardholders are likely to see their browser connect to unfamiliar domain names as a result of vendors' MPI implementations and the use of outsourced ACS implementations by card issuers, which might make it easier to perform phishing attacks on cardholders. General criticismVerifiability of site identityThe system involves a pop-up window or inline frame appearing during the online transaction process, requiring the cardholder to enter a password which, if the transaction is legitimate, their card issuer will be able to authenticate. The problem for the cardholder is determining if the pop-up window or frame is really from their card issuer when it could be from a fraudulent website attempting to harvest the cardholder's details. Such pop-up windows or script-based frames lack any access to any security certificate, eliminating any way to confirm the credentials of the implementation of 3-DS. The Verified-by-Visa system has drawn some criticism,[11][12][13][6] since it is hard for users to differentiate between the legitimate Verified-by-Visa pop-up window or inline frame, and a fraudulent phishing site. This is because the pop-up window is served from a domain which is:
In some cases, the Verified-by-Visa system has been mistaken by users for a phishing scam[14] and has itself become the target of some phishing scams.[15] The newer recommendation to use an inline frame (iframe) instead of a pop-up has reduced user confusion, at the cost of making it harder, if not impossible, for the user to verify that the page is genuine in the first place. As of 2022[update], web browsers do not provide a way to check the security certificate for the contents of an iframe. Some of these concerns in site validity for Verified-by-Visa are mitigated, however, as its current implementation of the enrollment process requires entering a personal message which is displayed in later Verified-by-Visa pop-ups to provide some assurance to the user the pop-ups are genuine.[16] Some card issuers also use activation-during-shopping (ADS),[17] in which cardholders who are not registered with the scheme are offered the opportunity of signing up (or forced into signing up) during the purchase process. This will typically take them to a form in which they are expected to confirm their identity by answering security questions which should be known to their card issuer. Again, this is done within the iframe where they cannot easily verify the site they are providing this information to—a cracked site or illegitimate merchant could in this way gather all the details they need to pose as the customer. Implementation of 3-D Secure sign-up will often not allow a user to proceed with a purchase until they have agreed to sign up to 3-D Secure and its terms and conditions, not offering any alternative way of navigating away from the page than closing it, thus suspending the transaction. Cardholders who are unwilling to take the risk of registering their card during a purchase, with the commerce site controlling the browser to some extent, can in some cases go to their card issuer's website in a separate browser window and register from there. When they return to the commerce site and start over they should see that their card is registered. The presence on the password page of the personal assurance message (PAM) that they chose when registering is their confirmation that the page is coming from the card issuer. This still leaves some possibility of a man-in-the-middle attack if the cardholder cannot verify the SSL server certificate for the password page. Some commerce sites will devote the full browser page to the authentication rather than using a frame (not necessarily an iFrame), which is a less secure object. In this case, the lock icon in the browser should show the identity of either the card issuer or the operator of the verification site. The cardholder can confirm that this is in the same domain that they visited when registering their card if it is not the domain of their card issuer. Mobile browsers present particular problems for 3-D Secure, due to the common lack of certain features such as frames and pop-ups. Even if the merchant has a mobile website, unless the issuer is also mobile-aware, the authentication pages may fail to render properly, or even at all. In the end, many[vague] analysts have concluded that the activation-during-shopping (ADS) protocols invite more risk than they remove and furthermore transfer this increased risk to the consumer. In some cases, 3-D Secure ends up providing little security to the cardholder, and can act as a device to pass liability for fraudulent transactions from the card issuer or retailer to the cardholder. Legal conditions applied to the 3-D Secure service are sometimes worded in a way that makes it difficult for the cardholder to escape liability from fraudulent "cardholder not present" transactions.[6] Geographic discriminationCard issuers and merchants may use 3-D Secure systems unevenly with regard to card issuers that issue cards in several geographic locations, creating differentiation, for example, between the domestic US- and non-US-issued cards. For example, since Visa and Mastercard treat the unincorporated US territory of Puerto Rico as a non-US international, rather than a domestic US location, cardholders there may confront a greater incidence of 3-D Secure queries than cardholders in the fifty states. Complaints to that effect have been received by Puerto Rico Department of Consumer Affairs "equal treatment" economic discrimination site.[18] 3-D Secure as strong customer authenticationVersion 2 of 3-D Secure, which incorporates one-time passcodes, is a form of software-based strong customer authentication as defined by the EU's Revised Directive on Payment Services (PSD2); earlier variants used static passwords, which are not sufficient to meet the directive's requirements. 3-D Secure relies upon the issuer actively being involved and ensuring that any card issued becomes enrolled by the cardholder; as such, acquirers must either accept unenrolled cards without performing strong customer authentication or reject such transactions, including those from smaller card schemes which do not have 3-D Secure implementations. Alternative approaches perform authentication on the acquiring side, without requiring prior enrolment with the issuer. For instance, PayPal's patented 'verification'[19] uses one or more dummy transactions are directed towards a credit card, and the cardholder must confirm the value of these transactions, although the resulting authentication can't be directly related to a specific transaction between merchant and cardholder. A patented[20] system called iSignthis splits the agreed transaction amount into two (or more) random amounts, with the cardholder then proving that they are the owner of the account by confirming the amounts on their statement.[21] ACCC blocks 3-D Secure proposalA proposal to make 3-D Secure mandatory in Australia was blocked by the Australian Competition & Consumer Commission (ACCC) after numerous objections and flaw-related submissions were received.[22] IndiaSome countries like India made use of not only CVV2, but 3-D Secure mandatory, a SMS code sent from a card issuer and typed in the browser when you are redirected when you click "purchase" to the payment system or card issuer system site where you type that code and only then the operation is accepted. Nevertheless, Amazon can still do transactions from other countries with turned-on 3-D Secure.[23] 3-D Secure 2.0In October 2016, EMVCo published the specification for 3-D Secure 2.0; it is designed to be less intrusive than the first version of the specification, allowing more contextual data to be sent to the customer's card issuer (including mailing addresses and transaction history) to verify and assess the risk of the transaction. The customer would only be required to pass an authentication challenge if their transaction is determined to be of a high risk. In addition, the workflow for authentication is designed so that it no longer requires redirects to a separate page, and can also activate out-of-band authentication via an institution's mobile app (which, in turn, can also be used with biometric authentication). 3-D Secure 2.0 is compliant with EU "strong customer authentication" mandates.[5][24][25] See also
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