Complex sentence: During the design phase of the ARPANET and the early Internet, the security aspects and needs of a public, international network could not be adequately anticipated, and consequently many Internet protocols exhibited vulnerabilities highlighted by network attacks and later security assessments.
Split into simpler sentences: During the design phase of the ARPANET and the early Internet, the security aspects and needs of a public, international network could not be adequately anticipated. Consequently, many Internet protocols exhibited vulnerabilities highlighted by network attacks and later security assessments.