This document focuses on the security-relevant features of the Flash Player client runtime, including those introduced in earlier versions of the product. While not attempting to distinguish between versions, some references are included where changes in the security model or potential operation of applications designed and implemented in earlier versions of Flash Player may significantly differ from the target Flash Player environment described here. Unless otherwise noted, however, this document assumes that the target platform for your development is Flash Player 9,0,124,0 running content that uses ActionScript 3.0.

If you have already implemented applications or web sites for an earlier version of Flash Player, the table at the end of this section lists documents that can provide information on potential implementation differences between your current Flash Player implementations and Flash Player 9,0,124,0 implementations. That is, applications you published for an earlier version of Flash Player may not run as expected if the end user is running Flash Player 9,0,124,0; refer to the additional resources listed to learn how to address these potential issues (see “Other sources of information” on page 3).

As you may know, Flash Player 9 introduced an entirely new ActionScript Virtual Machine, AVM2. AVM2 runs a much faster, ECMAScript standards-compliant language: ActionScript 3.0. AVM2 itself introduced some new architecture to this environment due to its enhanced byte code interpretation model. AVM1 remains available to run ActionScript 1.0 and 2.0 content, but this document doesn’t address implementation features specific to AVM1, ActionScript 1.0, or ActionScript 2.0.

There are no distinctions in the runtime security model between applications created using different development tools, such as Adobe AIR™, Adobe Flex™ Builder, the Adobe Flex SDK, or Adobe Flash.

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