OAuth 2.0 is an open standard for access delegation and authorization without the need to explicitly share password information. OAuth 2.0 allows providers of services to share a “valet key” with a third party, that allows limited access to services, possibly with an attached time constraint. In other words, OAuth 2.0 provides the mechanism for clients to access resources on behalf of the user or owner of those resources. The end user can select or authorize third-party access to resources, without ever sharing any secret credentials such as the username and password. – See more at: http://forgerock.com/oauth2/#sthash.DXYNvpRU.dpuf

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