Microsoft Technology Licensing, LLC

Philip Joseph Hallin

David Benson Cross

Thomas C Jones

Matthew W Thomlinson

Xiaohong Su

Kelvin Sjek Yiu

Haitao Li

Nelly L Porter

Anthony Paul Penta

Keith R Vogel

Muhammad Umar Janjua

Kelvin Shek Yiu

Anooshiravan Saboori

Charlie D Chase

Louis K Thomas

Kirt A Debique

Oludare Victor Obasanjo

Jonathan D Schwartz

Klaus U Schutz

Vishal Agarwal

Magnus Bo Gustaf Nyström

John J Lambert

Yogesh A Mehta

Stephen R Gordon

Bryston Mitsuo Nitta

Hao Zhuang

Violet Anna Barhudarian

Sunil Pai

Sarath Madakasira

Ryan M Hurst

Yu Lin Sie

Aleksandr Radutskiy

Jeremy Dominic Viegas

Vassil Dimitrov Bakalov

Anooshiravan Saboor

Atanas D Oskov

Daniel C Kitchener

Jeremy D Viegas

Establishing secure connections from a computing device to secure servers when the computing device starts with an incorrect system clock time that would ordinarily prohibit connection to the secure servers. A method includes attempting to access a plurality of secure servers. The method further includes, from each of the servers in the plurality of secure servers, receiving one or more certificates from the secure servers and metadata which includes a specification of time. The method further includes preventing secure applications from sending sensitive data to the plurality of secure servers until a system time has been approximated. The method further includes, from the secure specifications of time, approximating a current system time. The method further includes accessing another secure server using the approximated current system time and using the approximated current system time to validate a certificate from the other server.

Determine approximate current time on a client using secure protocol metadata

In many information security scenarios, a certificate issued by a certificate authority may be presented to a client in order to assert a trust level of a certificated item, such as a message or a web page. However, due to a decentralized structure and incomplete coordination among certificate authorities, the presence and exploitation of security vulnerabilities to issue untrustworthy certificates may be difficult to determine, particularly for an individual client. Presented herein are techniques for advising clients of the reputations of respective certificate authorities by evaluating the certificates issued by such certificate authorities, such as the number and types of domains certified by the certificate; the number and pattern of certificates issued for the domain; and the certification techniques used to issue the certificates. Such evaluation enables a determination of a certificate authority trust level that may be distributed to the clients in a certificate authority trust set.

Advising clients about certificate authority trust

In many information security scenarios, a certificate issued by a certificate authority on behalf of a domain is presented to a client in order to verify the identity of the domain. However, due to a decentralized structure and incomplete coordination among certificate authorities, the presence and exploitation of security vulnerabilities to issue untrustworthy certificates may be difficult for an individual client to determine. Presented herein are techniques for advising clients of the trustworthiness of respective certificate authorities by evaluating the certificates issued by such certificate authorities for suspicious indicators, such as hashcode collisions with other certificates and public key re-use. A trust level may be identified of respective certificate authorities according to the presence or absence of suspicious indicators in the certificates issued by the certificate authority, and a certificate authority trust set may be distributed to advise clients of the trustworthiness of certificates issued by the respective certificate authorities.

Certificate evaluation for certificate authority reputation advising

In many information security scenarios, a certificate issued by a certificating authority may be presented to a client in order to assert a trust level of a certificated item, such as a message or a web page. However, due to a decentralized structure and incomplete coordination among certificating authorities, the presence and exploitation of security vulnerabilities to issue untrustworthy certificates may be difficult to determine, particularly for an individual client. Presented herein are techniques for providing a certificating authority trust service that collects and evaluates certificates submitted to clients by certificating authorities, and advises the clients of a certificating authority trust level for respective certificating authorities (e.g., determined as a consensus of the evaluated certificates issued by the certificating authority). The clients may use a certificating authority trust set distributed by the certificating authority trust service to determine whether to trust a certificate issued from a particular certificating authority.

Certificating authority trust evaluation

One aspect relates to a process and associated device for managing digital ID lifecycles for application programs, and abstracting application programs for multiple types of credentials through a common Digital Identity Management System (DIMS) and Application Programming Interface (API) layer.

Digital identity management

Techniques for providing revocation information for revocable items are described. In implementations, a revocation service is employed to manage revocation information for various revocable items. For example, the revocation service can maintain a revoked list that includes revoked revocable items, such as revoked digital certificates, revoked files (e.g., files that are considered to the unsafe), unsafe network resources (e.g., a website that is determined to be unsafe), and so on. In implementations, the revocation service can communicate a revoked list to a client device to enable the client device to maintain an updated list of revocation information.

Revocation information for revocable items

Techniques for resource access authorization are described. In one or more implementations, an application identifier is used to control access to user resources by an application. A determination is made whether to allow the application to access the user resources by comparing an application identifier received from an authorization service with a system application identifier for the application obtained from a computing device on which the application is executing.

Resource access authorization

An exemplary system enabling credential roaming among a plurality of different computing devices may include an event handler to receive event notifications such as, e.g., a client logon. The event handler may invoke a management service in response to receiving an event notification. The management service may include a synchronizing module to synchronize a user's credentials with a remote directory service, such as, e.g., Active Directory, so that the user's credentials are available from any of a number of different computing devices.

Credential roaming in electronic computing systems

An efficient protocol for retrieving cryptographic evidence may be selected by evaluating a local policy and a number of relevant factors. Furthermore, updated cryptographic evidence may be prefetched during a time period in which there is a low volume of requests for cryptographic evidence. This low volume time period may be defined, approximately, as an overlapping window in which both a first cryptographic evidence publication and a second cryptographic evidence publication are valid.

Efficient retrieval of cryptographic evidence

Systems and methods for validating integrity of an executable file are described. In one aspect, multiple partial image hashes are generated, the combination of which represent a digest of an entire executable file. Subsequent to loading the executable file on a computing device, a request to page a portion of the executable file into memory for execution is intercepted. Responsive to intercepting the request, and prior to paging the portion into memory for execution, a validation hash of the portion is computed. The validation hash is compared to a partial hash of the multiple partial image hashes to determine code integrity of the portion. The partial hash represents a same code segment as the portion.

Systems and methods for validating executable file integrity using partial image hashes

Systems and methods are described for distributing and updating trusted certification authorities to computer systems and users. When a digital certificate is encountered during a secured electronic transaction, the root authority of the certificate is determined. It is then determined whether the root authority is a trusted authority by attempting to locate the root authority in a trusted root list. If the root authority is not included in the trusted root list, a remote site is accessed and an updated version of the trusted root list is downloaded. The new trusted root list is checked for the presence of the encountered certificate and, if found, the transaction is allowed to proceed. In one implementation, the entire trusted root list is not downloaded. Instead, if an appropriate digital certificate is located, then the certificate is downloaded and added to the trusted root list of the computer system. The transaction may then proceed.

Systems and methods for distributing trusted certification authorities

An update process is used to update root certificates in a root certificate store of a client computer, maintaining the integrity of the existing root certificates as well as any new root certificates. In accordance with certain aspects, the integrity of a certificate trust list identifying one or more root certificates is verified. The root certificate store of the client computer is modified in accordance with the certificate trust list if the integrity of the certificate trust list is verified.

Updating trusted root certificates on a client computer

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Townsend, WA, United States of America

Philip Joseph Hallin