This paper proposes a chaotic filter bank based computer cryptographic system for wireless applications. The signal is first decomposed via an analysis filter bank. Second, a pair of chaotic modulators is employed for performing the encryption on the subband signals. Third, the encrypted signals are upsampled and filtered so as to obtain the oversampled signals. Fourth, the oversampled signals are quantized via a multi-dimensional sigma delta modulator. Fifth, the quantized signals are encoded via a low density parity check code scheme. The encoded signals are transmitted via a wireless channel. At the receiver side, first the encoded signals are decoded via a low density parity check decoder. Then, a multi-dimensional filter is employed for separating the signals and the quantization noises. Next, the filtered signals are downsampled to obtain the same number of samples. After that, a pair of chaotic demodulators is employed for performing the decryption. Finally, a synthesis filter bank is used to reconstruct the original signal. In this paper, the filters in both the filter bank system and the multidimensional sigma delta modulator are designed. Computer numerical simulation results show that the proposed system outperforms the existing computer cryptographic systems.