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Q. Is the CVV2 number related to the actual credit card number? Is it a random number? Or is there some other way that the card issuer selects the CVV2 number to put on a card? —Preceding unsigned comment added by 207.233.79.134 ( talk • contribs) 23:27, 4 August 2005
A. I don't think MC or Visa require a particular algorithm, so it can be a random number stored in a secure lookup table, or it can be a derived number based on card data using a secret issuer key. —Preceding unsigned comment added by 38.112.4.254 ( talk • contribs) 21:02, 31 March 2006
Q. I would request to provide details on how does CVV verification process work. for example when a user enters his CVV in the payment termina intertface then what verification and validation processes occur in backgroung and the user gets authorized for the transaction. such information would be most appreciated. Lavkru ( talk) 09:48, 7 May 2013 (UTC)
I do not quite understand the security model underlying the CVV2. Isn't it the case that credit card numbers are typically obtained by making the user enter them on forged websites or by sniffing network traffic? Now what additional security do I gain if all such transactions will soon require to give the CVV2 as well? The same online methods used for stealing the credit card number can also be used to steal the CVV2.
I am just dealing with a transaction that requires me to send my credit card number and CVV2 via fax. The fax machine on the other side may stand in a crowded office and even the cleaning staff may be able to reprint the received faxes in the evening. How can the CVV2 verify that someone holds the card physically if its eventually printed out on some random paper sheets in offices all over the world? -- Markus Krötzsch 07:54, 11 August 2005 (UTC)
The CVV2 is just another layer of defence against fraud. If you have generated the card number or gained the card details by skimming you won't have access to the CVV2, reducing the potential for fraud. Dkam ( talk) 07:11, 12 July 2009 (UTC)
Question: Is the use of the CVV2 actually implemented at this time? I have been entering 3 random digits for all my online transactions, and so far, they have all been accepted. ( 24.66.0.192 ( talk) 21:36, 23 November 2010 (UTC))
The value of this system of security may be disputed. Anybody who can look at the card or recive payment orders with this validation code can know its value. For this reason it can not be anymore consider that the only person who know the code is the legittate owner of the card after the card is used the first time (or even before that, if anybody can look at the card). Morover the value is also known by the credit card society. AnyFile 14:21, 19 August 2005 (UTC)
There are some cases where a possible attacker has access to the credit card number, but not the CVV2. For instance, an employee at a store that takes credit cards may be able to make copies of large numbers of receipts, and the credit card number. In this case a person could make a large number of relatively small purchases on-line in a short period of time. Without the physical credit card or the CVV2, it is difficult to do this.
Of course, an employee would be able to record the CVV2 for any card that they physically handled, but in this case sales records would be able to identify the employee.
This is a guess, but it seems reasonable. —Preceding unsigned comment added by 82.93.59.73 ( talk • contribs) 18:18, 21 August 2005
I'm not sure how to phrase this in the article, but since the CVV2 can be stored prior to the completion of a transaction, in the case of a time-delayed transaction this storage period may in fact be very lengthy. I am currently working with a client that requires up to six months between collection and charging, and for technical reasons verification of the card is not possible at time of collection. I realize this sounds stupid, but it is allowed (though discouraged) in the specs. I'm not sure if this should be listed as a "drawback," since it seems to be a problem with a particular system's business requirements rather than the number itself. But that could be arguable about most of the drawbacks, so I'm not sure.
12.205.149.45 22:54, 3 August 2007 (UTC)
There is an incorrect statement in this article: "The CVV2 is a 3- or 4-digit value printed on the card or signature strip, but not encoded on the magnetic stripe."
In this article, it is stated that the magnetic strip may include CVV:
http://en.wikipedia.org/wiki/Magnetic_stripe
Financial cards Discretionary data — may include Pin Verification Key Indicator (PVKI, 1 character), Pin Verification Value (PVV, 4 characters), Card Verification Value or Card Verification Code (CVV or CVK, 3 characters)
Jimmied999 14:19, 14 August 2007 (UTC) http://www.ded.co.uk/magnetic-stripe-card-details.html
Don't get inforamtion for wikipedia — Preceding unsigned comment added by 2601:18D:4601:2CD0:F413:6350:E36B:B11D ( talk) 18:23, 23 March 2019 (UTC)
When did this whole CSC thing get started? I think it would be nice to have a "History" section in this article. I know that 10 or 20 years ago, cards didn't have this. Westwind273 17:30, 17 September 2007 (UTC)
It seems like the article should say... —Preceding unsigned comment added by 206.168.188.130 ( talk) 19:02, 26 October 2007 (UTC)
I understand that CVV2 is designed to verify that the person making "card not present" transactions occurring over the Internet, by mail, fax or over the phone is holding the physical card at the time of transaction. However, CVV2 code is just a 3-4 digit number. Unlike a PIN code or password, the CVV2 code can never be changed.
Anyone who can copy the 16-digit credit card number and it's expiry month, can very easily copy this short code. Once the person has copied the three details, he/she can easily make an Internet transaction or a similar "card not present" transaction even though he may not be holding the physical card. This fraud can be attempted very easily using, for example, a photograph of the back side of credit card. (The photo can be mirrored to reveal the credit card number and expiry date, eliminating the need for a photo of the front side.)
Why is this limitation not acknowledged? It is the most serious of all limitations of CVV2 and it's a 'self-defying' limitation. That means, it defeats the very purpose of CVV2, rendering it useless. I think it should be mentioned in the Limitations section.
My suggestion is, the CVV2 code should be sent as a separate document from the Bank, and the user should be requested to memorize the code and destroy the document. For current cards, a strong thin black sticker can be used to cover up the CVV2 code, after the cardholder has memorized it. This will prevent shopkeepers and store cashiers from copying down the CVV2 code.
I understand my suggestion is not fool-proof as more services are starting to require CVV2 code. However, I believe the legitimate services that require CVV2 code will discard the code and destroy all records once the transaction has been made. It protects against fraud during "card present" signature-based transactions, and against friends or significant other who are taking a look at your wallet. -- ADTC ( talk) 15:02, 16 December 2008 (UTC)
I could not find a Spanish version Wikipedia page for Card Security Code. Can someone please post it here? —Preceding unsigned comment added by 209.251.128.198 ( talk) 21:50, 9 September 2009 (UTC)
Amex name for CVV2 is CID/4DBC
4DBC stands for 4 digit batch code, recognising the fact that the security number is 4 digits on the front of the card. Would be good to insert this into the main text
Reference 3 to visa rules appears to go to a chargeback information page instead of the rules. Sorry I do not have the time to go searching for it today... Skaterdad ( talk) 00:58, 28 March 2011 (UTC)
http://www.zeit.de/2011/21/Kreditkarten-Sicherheit (german) —Preceding unsigned comment added by 84.157.21.179 ( talk) 10:12, 21 May 2011 (UTC)
It has not remotely been hacked. They simply brute forced it by trying authorizations en masse at various websites. The fact that this was allowed to occur means that the card issuers simply were lacking in their fraud detection, I'm sure at this point the issuers simply look for a large amount of attempted authorizations and flag the card. Thus, the CVV is not weakened as a result. You can also brute force card numbers by generating all card numbers that have a valid Luhn check and attempt authorizations on those, but in cases like this the gateway provider would probably alert the store in question. Brute force methods are not a good way to do fraud on a large scale. 98.103.160.18 ( talk) 15:09, 7 April 2017 (UTC)
The article is correct that security codes are often used for mail transactions, but recording the code on paper is prohibited by all of the credit card companies. Does this deserve its own section in the article? If nothing else, a clarification should be made using the AmEx language: they're for real-time card-not-present transactions.
This is definitely controversial, as it's an area where common practice stands in opposition to official policy, so I'd like to see some discussion before making any changes.
Avoid CVV2 Storage. All merchants are prohibited from storing CVV2 data. When asking a cardholder for CVV2, merchants must not document this information on any kind of paper order form or store it on any database. [Rules for Visa Merchants, 2007, page 12]
Merchants ... must not store card validation code 2 (CVC 2) data in any manner for any purpose. ... At its discretion, MasterCard may impose a noncompliance assessment of up to USD 100,000 per each individual violation of this Standard, with a maximum aggregate assessment of USD 500,000 for additional or continuing violations during any consecutive 12-month period. [Security Rules and Procedures-Merchant Edition, Section 10.2, July 2009]
CID numbers must not be stored for any purpose. They are available for real time Transactions only. [American Express Merchant Reference Guide – U.S., section 5.10, 2009] — Preceding unsigned comment added by Coloradoauthor ( talk • contribs) 22:21, 16 May 2012 (UTC)
Have noticed that there is a 3 digit code at the right hand end of the signature panel on my American Express cards (those from AXP itself and those from two other independent issuers). I would imagine that this is for the benefit of procedures or hardware that only allow for a 3 digit CVV. knoodelhed ( talk) 17:38, 15 October 2013 (UTC)
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Why is this article primarily talking about magnetic stripes? Surely that is decades-out-of-date tech, replaced by smartcard chips ages ago? Is this article out of date, or are there still some countries (3rd world maybe?) that still use mag stripes? Can this article be updated to primarily refer to chips please? Andrew Oakley ( talk) 09:50, 30 July 2020 (UTC)
Why does the CVV number also compile the number text of 3 or 4, why is it that way 105.112.176.194 ( talk) 15:49, 11 August 2022 (UTC)
I’m new to this who do I ask for help 2601:152:302:59A6:3057:B73E:6C08:5946 ( talk) 17:14, 13 October 2022 (UTC)
The first sentence says "…is a series of numbers that, in addition to the bank card number, is printed (but embossed) on a credit or debit card." Shouldn't that be "NOT" embossed? 24.16.93.143 ( talk) 04:05, 19 June 2024 (UTC)
![]() | This article is rated C-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||||||||||||||||||
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Q. Is the CVV2 number related to the actual credit card number? Is it a random number? Or is there some other way that the card issuer selects the CVV2 number to put on a card? —Preceding unsigned comment added by 207.233.79.134 ( talk • contribs) 23:27, 4 August 2005
A. I don't think MC or Visa require a particular algorithm, so it can be a random number stored in a secure lookup table, or it can be a derived number based on card data using a secret issuer key. —Preceding unsigned comment added by 38.112.4.254 ( talk • contribs) 21:02, 31 March 2006
Q. I would request to provide details on how does CVV verification process work. for example when a user enters his CVV in the payment termina intertface then what verification and validation processes occur in backgroung and the user gets authorized for the transaction. such information would be most appreciated. Lavkru ( talk) 09:48, 7 May 2013 (UTC)
I do not quite understand the security model underlying the CVV2. Isn't it the case that credit card numbers are typically obtained by making the user enter them on forged websites or by sniffing network traffic? Now what additional security do I gain if all such transactions will soon require to give the CVV2 as well? The same online methods used for stealing the credit card number can also be used to steal the CVV2.
I am just dealing with a transaction that requires me to send my credit card number and CVV2 via fax. The fax machine on the other side may stand in a crowded office and even the cleaning staff may be able to reprint the received faxes in the evening. How can the CVV2 verify that someone holds the card physically if its eventually printed out on some random paper sheets in offices all over the world? -- Markus Krötzsch 07:54, 11 August 2005 (UTC)
The CVV2 is just another layer of defence against fraud. If you have generated the card number or gained the card details by skimming you won't have access to the CVV2, reducing the potential for fraud. Dkam ( talk) 07:11, 12 July 2009 (UTC)
Question: Is the use of the CVV2 actually implemented at this time? I have been entering 3 random digits for all my online transactions, and so far, they have all been accepted. ( 24.66.0.192 ( talk) 21:36, 23 November 2010 (UTC))
The value of this system of security may be disputed. Anybody who can look at the card or recive payment orders with this validation code can know its value. For this reason it can not be anymore consider that the only person who know the code is the legittate owner of the card after the card is used the first time (or even before that, if anybody can look at the card). Morover the value is also known by the credit card society. AnyFile 14:21, 19 August 2005 (UTC)
There are some cases where a possible attacker has access to the credit card number, but not the CVV2. For instance, an employee at a store that takes credit cards may be able to make copies of large numbers of receipts, and the credit card number. In this case a person could make a large number of relatively small purchases on-line in a short period of time. Without the physical credit card or the CVV2, it is difficult to do this.
Of course, an employee would be able to record the CVV2 for any card that they physically handled, but in this case sales records would be able to identify the employee.
This is a guess, but it seems reasonable. —Preceding unsigned comment added by 82.93.59.73 ( talk • contribs) 18:18, 21 August 2005
I'm not sure how to phrase this in the article, but since the CVV2 can be stored prior to the completion of a transaction, in the case of a time-delayed transaction this storage period may in fact be very lengthy. I am currently working with a client that requires up to six months between collection and charging, and for technical reasons verification of the card is not possible at time of collection. I realize this sounds stupid, but it is allowed (though discouraged) in the specs. I'm not sure if this should be listed as a "drawback," since it seems to be a problem with a particular system's business requirements rather than the number itself. But that could be arguable about most of the drawbacks, so I'm not sure.
12.205.149.45 22:54, 3 August 2007 (UTC)
There is an incorrect statement in this article: "The CVV2 is a 3- or 4-digit value printed on the card or signature strip, but not encoded on the magnetic stripe."
In this article, it is stated that the magnetic strip may include CVV:
http://en.wikipedia.org/wiki/Magnetic_stripe
Financial cards Discretionary data — may include Pin Verification Key Indicator (PVKI, 1 character), Pin Verification Value (PVV, 4 characters), Card Verification Value or Card Verification Code (CVV or CVK, 3 characters)
Jimmied999 14:19, 14 August 2007 (UTC) http://www.ded.co.uk/magnetic-stripe-card-details.html
Don't get inforamtion for wikipedia — Preceding unsigned comment added by 2601:18D:4601:2CD0:F413:6350:E36B:B11D ( talk) 18:23, 23 March 2019 (UTC)
When did this whole CSC thing get started? I think it would be nice to have a "History" section in this article. I know that 10 or 20 years ago, cards didn't have this. Westwind273 17:30, 17 September 2007 (UTC)
It seems like the article should say... —Preceding unsigned comment added by 206.168.188.130 ( talk) 19:02, 26 October 2007 (UTC)
I understand that CVV2 is designed to verify that the person making "card not present" transactions occurring over the Internet, by mail, fax or over the phone is holding the physical card at the time of transaction. However, CVV2 code is just a 3-4 digit number. Unlike a PIN code or password, the CVV2 code can never be changed.
Anyone who can copy the 16-digit credit card number and it's expiry month, can very easily copy this short code. Once the person has copied the three details, he/she can easily make an Internet transaction or a similar "card not present" transaction even though he may not be holding the physical card. This fraud can be attempted very easily using, for example, a photograph of the back side of credit card. (The photo can be mirrored to reveal the credit card number and expiry date, eliminating the need for a photo of the front side.)
Why is this limitation not acknowledged? It is the most serious of all limitations of CVV2 and it's a 'self-defying' limitation. That means, it defeats the very purpose of CVV2, rendering it useless. I think it should be mentioned in the Limitations section.
My suggestion is, the CVV2 code should be sent as a separate document from the Bank, and the user should be requested to memorize the code and destroy the document. For current cards, a strong thin black sticker can be used to cover up the CVV2 code, after the cardholder has memorized it. This will prevent shopkeepers and store cashiers from copying down the CVV2 code.
I understand my suggestion is not fool-proof as more services are starting to require CVV2 code. However, I believe the legitimate services that require CVV2 code will discard the code and destroy all records once the transaction has been made. It protects against fraud during "card present" signature-based transactions, and against friends or significant other who are taking a look at your wallet. -- ADTC ( talk) 15:02, 16 December 2008 (UTC)
I could not find a Spanish version Wikipedia page for Card Security Code. Can someone please post it here? —Preceding unsigned comment added by 209.251.128.198 ( talk) 21:50, 9 September 2009 (UTC)
Amex name for CVV2 is CID/4DBC
4DBC stands for 4 digit batch code, recognising the fact that the security number is 4 digits on the front of the card. Would be good to insert this into the main text
Reference 3 to visa rules appears to go to a chargeback information page instead of the rules. Sorry I do not have the time to go searching for it today... Skaterdad ( talk) 00:58, 28 March 2011 (UTC)
http://www.zeit.de/2011/21/Kreditkarten-Sicherheit (german) —Preceding unsigned comment added by 84.157.21.179 ( talk) 10:12, 21 May 2011 (UTC)
It has not remotely been hacked. They simply brute forced it by trying authorizations en masse at various websites. The fact that this was allowed to occur means that the card issuers simply were lacking in their fraud detection, I'm sure at this point the issuers simply look for a large amount of attempted authorizations and flag the card. Thus, the CVV is not weakened as a result. You can also brute force card numbers by generating all card numbers that have a valid Luhn check and attempt authorizations on those, but in cases like this the gateway provider would probably alert the store in question. Brute force methods are not a good way to do fraud on a large scale. 98.103.160.18 ( talk) 15:09, 7 April 2017 (UTC)
The article is correct that security codes are often used for mail transactions, but recording the code on paper is prohibited by all of the credit card companies. Does this deserve its own section in the article? If nothing else, a clarification should be made using the AmEx language: they're for real-time card-not-present transactions.
This is definitely controversial, as it's an area where common practice stands in opposition to official policy, so I'd like to see some discussion before making any changes.
Avoid CVV2 Storage. All merchants are prohibited from storing CVV2 data. When asking a cardholder for CVV2, merchants must not document this information on any kind of paper order form or store it on any database. [Rules for Visa Merchants, 2007, page 12]
Merchants ... must not store card validation code 2 (CVC 2) data in any manner for any purpose. ... At its discretion, MasterCard may impose a noncompliance assessment of up to USD 100,000 per each individual violation of this Standard, with a maximum aggregate assessment of USD 500,000 for additional or continuing violations during any consecutive 12-month period. [Security Rules and Procedures-Merchant Edition, Section 10.2, July 2009]
CID numbers must not be stored for any purpose. They are available for real time Transactions only. [American Express Merchant Reference Guide – U.S., section 5.10, 2009] — Preceding unsigned comment added by Coloradoauthor ( talk • contribs) 22:21, 16 May 2012 (UTC)
Have noticed that there is a 3 digit code at the right hand end of the signature panel on my American Express cards (those from AXP itself and those from two other independent issuers). I would imagine that this is for the benefit of procedures or hardware that only allow for a 3 digit CVV. knoodelhed ( talk) 17:38, 15 October 2013 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Card security code. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{
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).
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
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(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 01:32, 15 November 2016 (UTC)
Why is this article primarily talking about magnetic stripes? Surely that is decades-out-of-date tech, replaced by smartcard chips ages ago? Is this article out of date, or are there still some countries (3rd world maybe?) that still use mag stripes? Can this article be updated to primarily refer to chips please? Andrew Oakley ( talk) 09:50, 30 July 2020 (UTC)
Why does the CVV number also compile the number text of 3 or 4, why is it that way 105.112.176.194 ( talk) 15:49, 11 August 2022 (UTC)
I’m new to this who do I ask for help 2601:152:302:59A6:3057:B73E:6C08:5946 ( talk) 17:14, 13 October 2022 (UTC)
The first sentence says "…is a series of numbers that, in addition to the bank card number, is printed (but embossed) on a credit or debit card." Shouldn't that be "NOT" embossed? 24.16.93.143 ( talk) 04:05, 19 June 2024 (UTC)