Extended Validation Certificate
An Extended Validation Certificate (EV) is an X.509 public key certificate issued according to a specific set of identity verification criteria. These criteria require extensive verification of the requesting entity's identity by the certificate authority (CA) before a certificate is issued. Certificates issued by a CA under the EV guidelines are not structurally different from other certificates (and hence provide no stronger cryptography than other, cheaper certificates), but are designated with a CA-specific policy identifier so that EV-aware software can recognize them.
The criteria for issuing EV certificates are defined by the Guidelines for Extended Validation Certificates, currently (as of May 2012) at version 1.4. The guidelines are produced by the CA/Browser Forum, a voluntary organization whose members include leading CAs and vendors of Internet software, as well as representatives from the legal and audit professions.
In 2005 Melih Abdulhayoglu, CEO of the Comodo Group, convened the first meeting of the organization that became the CA/Browser Forum, hoping to improve standards for issuing SSL certificates. On June 12, 2007, the CA/Browser Forum officially ratified the first version of the Extended Validation (EV) SSL Guidelines, which took effect immediately. The formal approval successfully brought to a close more than two years of effort, and provided the infrastructure for trusted Web site identity on the Internet. Then, in April 2008, the Forum announced version 1.1 of the Guidelines, building on the practical experience of its member CAs and Relying-Party Application Software Suppliers gained in the months since the first version was approved for use.
An important motivation for using digital certificates with SSL was to add trust to online transactions by requiring website operators to undergo vetting with a certificate authority (CA) in order to get an SSL certificate. However, commercial pressures have led some CAs to introduce "domain validation only" SSL certificates for which minimal verification is performed of the details in the certificate.
Most browsers' user interfaces did not clearly differentiate between low-validation certificates and those that have undergone more rigorous vetting. Since any successful SSL connection causes the padlock icon to appear, users are not likely to be aware of whether the website owner has been validated or not. As a result, fraudsters (including phishing websites) have started to use SSL to add perceived credibility to their websites.
By establishing stricter issuing criteria and requiring consistent application of those criteria by all participating CAs, EV SSL certificates are intended to restore confidence among users that a website operator is a legally established business or organization with a verifiable identity.
That said, there is still the concern that the same lack of accountability that led to the loss of public confidence in ordinary certificates, will lead to lax certification practices that will erode the value of EV certificates as well.
Issuing criteria 
Only CAs who pass an independent audit as part of their WebTrust (or equivalent) review may offer EV, and all CAs globally must follow the same detailed issuance requirements which aim to:
- Establish the legal identity as well as the operational and physical presence of website owner;
- Establish that the applicant is the domain name owner or has exclusive control over the domain name; and
- Confirm the identity and authority of the individuals acting for the website owner, and that documents pertaining to legal obligations are signed by an authorised officer.
User interface 
Browsers with EV support display more information for EV certificates than for previous SSL certificates. Microsoft Internet Explorer 7, Mozilla Firefox 3, Safari 3.2, Opera 9.5, and Google Chrome all provide EV support.
The Extended Validation guidelines require participating Certificate Authorities to assign a specific EV identifier, which is registered with the browser vendors who support EV once the Certificate Authority has completed an independent audit and met other criteria. The browser matches the EV identifier in the SSL certificate with the one it has registered for the CA in question: if they match, and the certificate is verified as current, the SSL certificate receives the enhanced EV display in the browser's user interface. In most implementations, the enhanced display includes:
- The name of the company or entity that owns the certificate.
- The name of the SSL Certificate Authority (CA) that issued the EV certificate.
- A distinctive color, usually green, shown in the address bar to indicate that a valid EV certificate was received.
Most of the Extended Validation SSL Certificates are compatible with the following browsers:
- Google Chrome
- IE 7.0+
- Mozilla 3+
- Safari 3.2+
- Opera 9.5+
Supported Mobile Device Browsers 
- Microsoft Pocket Internet Explorer
- Palm / Handspring Blazer 2.0+
- Netfront 3.0+
- Safari for iOS (iPhone 3GS and later)
Extended Validation supports all current releases of commercial and freeware web servers supporting SSL v.3. Supported servers include:
|Apache + mod_ssl||Lotus Domino Go 18.104.22.168 and higher|
|Apache + Raven||Lotus Domino 4.6 and higher|
|Apache + Raven 1.5x||Microsoft Internet Information Server 4.0|
|Apache + SSLeay||Microsoft Internet Information Server 5.0|
|BEA WebLogic||Netscape Enterprise/Fast Track|
|C2Net Stronghold||O'Reilly WebSite Professional 2.X|
|Cobalt RaQ3/RaQ4 "Main Site"||Stronghold 3|
|Cobalt RaQ3 "Virtual Site"||WebSTAR 4|
|Cobalt RaQ4 "Virtual Site"||WebSTAR V|
|IBM HTTP||Zeus Web Server v3|
|iPlanet Enterprise Server 4.1|
Extended Validation certificate identification 
EV certificates are standard x.509 digital certificates. The primary way to identify an EV certificate is by referencing the Certificate Policies extension field. Each issuer uses a different object identifier (OID) in this field to identify their EV certificates, and each OID is documented in the issuer's Certification Practice Statement. As with root certificate authorities in general, browsers may not recognize all issuers.
|Issuer||OID||Certification Practice Statement|
||AffirmTrust CPS v1.1, p. 4|
||a.sign SSL EV CPS v1.3.4|
||Buypass Class 3 EV CPS, p. 10|
||Camerfirma CPS v3.2.3|
||Comodo EV CPS, p. 28|
||DigiCert EV CPS v. 1.0.3, p. 56|
||DigiNotar CPS v 3.5, p. 2|
||Entrust EV CPS, p. 37|
||GeoTrust EV CPS v. 2.6, p. 28|
||GlobalSign EV CPS v. 6.5, p. 24|
||Go Daddy EV CPS v. 2.0, p. 42|
||DOCUMENTACIÓN ESPECÍFICA PARA EL CERTIFICADO DE SERVIDOR SEGURO SSL EV, p. 5
DOCUMENTACIÓN ESPECÍFICA PARA EL CERTIFICADO DE SEDE ELECTRÓNICA EV, p. 5
||KEYNECTIS EV CA CPS v 0.3, p. 10|
||Network Solutions EV CPS v. 1.1, 2.4.1|
||QuoVadis Root CA2 CP/CPS, p. 34|
|SECOM Trust Systems||
||SECOM Trust Systems EV CPS (in Japanese), p. 2|
||Starfield EV CPS v. 2.0, p. 42|
|StartCom Certification Authority||
||StartCom CPS, no. 4|
||SwissSign Gold CA-G2 CP/CPS, p. 7|
||Thawte EV CPS v. 3.3, p. 95|
||SecureTrust EV CPS v1.1.1, p. 5|
||VeriSign EV CPS v. 3.3, p. 87|
|Verizon Business (formerly Cybertrust)||
||Cybertrust CPS v.5.2, p. 20|
Online Certificate Status Protocol 
The criteria for issuing Extended Validation certificates do not require issuing Certificate Authorities to immediately support Online Certificate Status Protocol for revocation checking. However, the requirement for a timely response to revocation checks by the browser has prompted most Certificate Authorities that had not previously done so to implement OCSP support. Section 26-A of the issuing criteria requires CAs to support OCSP checking for all certificates issued after Dec. 31, 2010.
Availability to small businesses 
Since EV certificates are being promoted and reported as a mark of a trustworthy website, some small business owners have voiced concerns that EV certificates give undue advantage to large businesses. The published drafts of the EV Guidelines excluded unincorporated business entities, and early media reports focused on that issue. Version 1.0 of the EV Guidelines was revised to embrace unincorporated associations as long as they were registered with a recognized agency, greatly expanding the number of organizations that qualified for an Extended Validation Certificate.
Effectiveness against phishing attacks 
In 2006, researchers at Stanford University and Microsoft Research conducted a usability study of the EV display in Internet Explorer 7. Their paper concluded that "participants who received no training in browser security features did not notice the extended validation indicator and did not outperform the control group", whereas "participants who were asked to read the Internet Explorer help file were more likely to classify both real and fake sites as legitimate".
While proponents of EV Certificates claim they help against phishing attacks, security expert Peter Gutmann states the new class of certificates restore a CA's profits which were eroded due to the race to the bottom that occurred among issuers in the industry. Gutmann calls this phenomenon "PKI-Me-Harder".
The introduction ... of so-called high-assurance or extended validation (EV) certificates that allow CAs to charge more for them than standard ones, is simply a case of rounding up twice the usual number of suspects - presumably somebody’s going to be impressed by it, but the effect on phishing is minimal since it’s not fixing any problem that the phishers are exploiting. Indeed, cynics would say that this was exactly the problem that certificates and CAs were supposed to solve in the first place, and that “high-assurance” certificates are just a way of charging a second time for an existing service. A few years ago certificates still cost several hundred dollars, but now that the shifting baseline of certificate prices and quality has moved to the point where you can get them for $9.95 (or even for nothing at all) the big commercial CAs have had to reinvent themselves by defining a new standard and convincing the market to go back to the prices paid in the good old days.
This deja-vu-all-over-again approach can be seen by examining Verisign’s certificate practice statement (CPS), the document that governs its certificate issuance. The security requirements in the EV-certificate 2008 CPS are (except for minor differences in the legalese used to express them) practically identical to the requirements for Class 3 certificates listed in Verisign’s version 1.0 CPS from 1996. EV certificates simply roll back the clock to the approach that had already failed the first time it was tried in 1996, resetting the shifting baseline and charging 1996 prices as a side-effect. There have even been proposals for a kind of slidingwindow approach to certificate value in which, as the inevitable race to the bottom cheapens the effective value of established classes of certificates, they’re regarded as less and less effective by the software that uses them...
See also 
- Transport Layer Security (TLS)
- Certificate authority (CA)
- Comparison of SSL certificates for web servers
- Guidelines for Extended Validation Certificates
- CA/Browser Forum Members
- Hagai Bar-El. "The Inevitable Collapse of the Certificate Model". Hagai Bar-El on Security.
- "Why can’t I get a Wildcard Extended Validation (EV) SSL Certificate?". Network Solutions. Retrieved 2013-04-16.
- Evers, Joris (February 2, 2007). "IE 7 gives secure Web sites the green light". CNet. Retrieved 2010-02-27. "The colored address bar, a new weapon in the fight against phishing scams, is meant as a sign that a site can be trusted, giving Web surfers the green light to carry out transactions there."
- Richmond, Riva (December 19, 2006). "Software to Spot 'Phishers' Irks Small Concerns". The Wall Street Journal. Retrieved 2010-02-27.
- Jackson, Collin; Daniel R. Simon, Desney S. Tan, Adam Barth. "An Evaluation of Extended Validation and Picture-in-Picture Phishing Attacks" (PDF). Usable Security 2007.
- "Common Questions About Extended Validation EV SSL". DigiCert, Inc. Retrieved 15 May 2013.
- Gutmann, Peter (2013). Engineering Security. pp. 63–64. Retrieved 15 May 2013.
- CA/Browser Forum Web site
- CA/Browser Extended Validation Guidelines
- Microsoft information on EV in IE7
- CAs approved for EV in Microsoft IE7