Apps are secured or security-wrapped either before they are downloaded onto a device, such as a smartphone or tablet device, or after they are downloaded but before they are allowed to access the device operating system and cause any potential damage to the device. An app provider, such as an employer or a cellphone provider, can secure its apps before consumers download an app from their app store or marketplace. The app is secured before it is allowed to access the operating system of the device, thereby preventing the app from malicious behavior. Core object code of the app is obtained and the digital signature is removed. App object code is substituted with security program object code, thereby creating a security-wrapped app. The security-wrapped app is prepared for execution on the device and is re-signed with a new key.