Abstract: This disclosure provides methods for verifying the integrity of an additive manufacturing process during or after a three-dimensional (3D) print job. The methods include at least one of three validation layers: an acoustic layer, a spatial sensing layer, and a material verification layer. For the acoustic layer, the method includes determining the presence of a signature audio signal. For the spatial sensing layer, the method includes comparing a recorded trajectory with a reference trajectory. The method also includes determining the presence of a signature trajectory. For the material verification layer, the method includes determining the location of a special material in a 3D printed object based on a predetermined pattern in which the special material embedded in a filament. The methods allow for detecting alteration in the additive manufacturing process.