.asec is the

filename extension A filename extension, file name extension or file extension is a suffix to the name of a computer file (for example, .txt, .mp3, .exe) that indicates a characteristic of the file contents or its intended use. A filename extension is typically d ...

of an ''Android secure encrypted'' (''ASEC'') file. This file extension is specifically associated with

Google Google LLC (, ) is an American multinational corporation and technology company focusing on online advertising, search engine technology, cloud computing, computer software, quantum computing, e-commerce, consumer electronics, and artificial ...

Android operating system Android is an operating system based on a modified version of the Linux kernel and other open-source software, designed primarily for touchscreen-based mobile devices such as smartphones and tablets. Android has historically been developed by ...

. It was first introduced with Android 2.2 (codenamed Froyo) in May 2010. The purpose of ASEC is to prevent existing applications from being modified or corrupted by other programs. Applications moved to an

SD card Secure Digital (SD) is a proprietary, non-volatile, flash memory card format developed by the SD Association (SDA). Owing to their compact size, SD cards have been widely adopted in a variety of portable consumer electronics, including dig ...

are

encrypted In cryptography, encryption (more specifically, encoding) is the process of transforming information in a way that, ideally, only authorized parties can decode. This process converts the original representation of the information, known as plain ...

and stored there in an ASEC file. These files can then be found under the folder on the SD card. If an application is moved back to its device's local storage, the file is decrypted from the ASEC file format to a basic APK (Android Package) file format.

References

{{Reflist Android (operating system) Computer file formats Android (operating system) software