The invention discloses digital steganography and digital extraction methods with compressed audio as a masking carrier. In a digital steganography method, the window shape of audio particle data is selected to be used as a steganography object and is switched to realize hiding of bits of secret information, and the code stream length of the compressed audio containing the secret information and the code stream length of the compressed audio containing no secret information are constant, thus the problems of code bit rate increment, document length variation and the like of the whole compressed audio due to steganography operation are avoided, and the safety of the secret information is effectively ensured; and in a digital extraction method, the window shape of the audio particle data corresponding to frame information obtained through decoding is determined, then the bits of the secret information are directly obtained according to the window shape, and because the window shape can be obtained through extraction from the frame information when the frame information of the audio particle data is decoded, the audio particle data does not require to be decoded, thus the real-time property of a secret information extraction process is effectively improved.