A new optical encryption(OE) scheme based on multiple wavelength light source for computational ghost imaging(CGI) is proposed. In the scheme, using red-green-blue three color light to generate multiple random speckles, the phase mask matrix of speckles sequence is modulated into a random Toeplitz matrix. The corresponding wavelengths of speckles are random three color light wavelengths. The phase mask and wavelength are simultaneously used as two keys for optical encryption. After all speckles arrive at an object at the same axial distance, the compressed sensing technology is used to restore the object image. Numerical simulation shows that the scheme can completely restore the object image under all known conditions of the dual key, and the key stealing rate is less than 60%, which can not get the image information of the object. To get the same quality image, the number of measurement and transmission key is only 1/3 based on the double key optical encryption scheme of ghost imaging.