ULTRA-WIDEBAND (UWB) is a new technology that provides high data rate and low power consumption. In this work, first, a comparison is proposed between each of UWB system and other UWB system after adding Code division multiple access (CDMA) technology, DS/CDMA UWB system is found as the best that can scale the data rate to Giga bit/second. This system has increase speed and security based on CDMA technology and AWGN channel. Secondly, single channel wireless network with Variable Processing Gain (VPG) CDMA scheme is proposed with CDMA spreading code (Walsh code & m-sequence code) in the LB and HB of the XtremeSpectrum company proposal instead of using one or multi piconets channels with ternary code. Third, DS/CDMA UWB is modified to enable increase security with all proposed security methods. Fourth, a comparison is proposed among AES and RC5/RC6 encryption algorithms to choose the best encryption algorithm to achieve the high data confidentiality in the system. Finally, multiple CDMA security methods with its enhancements and other proposed security methods are proposed to increase built-in information confidentiality in the DS/CDMA UWB system against attackers. The results show, with VPG CDMA scheme in single channel of DS/CDMA UWB system, high and different data rates are achieved in the system with; built in security, encrypt spreading code, secure scrambling at chip rate, secure scrambling at user data & interleaver methods up to 684 Mb/s in LB and 1368 Mb/s in HB using Walsh code, 456 Mb/s in LB and 912 in HB using m-sequence spreading code. DS/CDMA UWB system with; joint code method and hybrid methods#1,#2 achieve data rate up to 342 Mb/s in LB, 684 Mb/s in HB using Walsh code, 228 Mb/s in LB and 456 Mb/s in HB using m-sequence code. Large numbers of users is achieved in the system up to 128 users using Walsh code and 127 users using m-sequence code where the building is the assumption in this thesis. The system is hard to attack with all proposed scenarios of security methods. The proposed secure scrambling at user data method is very efficient due to achieving secure system with very small BER & moderate complexity load. Three hybrid methods#1,#2 provide very secure system with more than one security levels in case of break the 128 AES key. Also, joint code method, hybrid method #2 are very efficient due to achieving secure system with multiple security levels, less complexity load & reasonable BER and this error is decrease with increasing code length. In addition, encrypt spreading code, secure scrambling at chip rate &hybrid method#1 are not efficient due to high BER and high complexity load in secure scrambling at chip rate method &hybrid method#1.