Method for protecting installed software on Android platform

The invention discloses a method for protecting installed software on an Android platform. The method comprises the following steps: when an application program is installed, first, encrypting a digest value of an optimized executable code file by utilizing a private key, and finally, storing the encrypted digest value of the file; when the application program is installed, first, performing one-way hash operation on the optimized executable file to generate the digest value of the file, then, encrypting the generated digest value by utilizing a key, and finally, performing the one-way hash operation on the encrypted digest value again to obtain the digest value which serves as a root file for authentication. According to the method, the deficiency of an existing protecting scheme can be overcome, and the potential security hazard of an Android authentication mechanism can be eliminated; the Android system structure is not modified; any module is not required to be added; a developer of the application program is not affected.