Based on the embedded system and cipher technology, a digital speech scrambler is designed and realized in this thesis which can security transmit speech, video, fax and data.

• 本文利用嵌入式系统技术和密码学技术，利用现有的PSTN或ISDN，采用先进的分组加密算法，设计实现了基于EPSON 33209 体系的数字语音保密电话，实现语音、视频、传真及数据的安全传输。