So security and safeguarding of information on computer networks has become one of the most import problems , because of the diversity of network ' s connection , the asymmetry of terminal ' s distribution , the interconnection of computer and the attack of hacker , cracker and vicious software . it is more important for military ' s automation commanding network and banks whose network communicates sensitive data . thus we should apply sufficient safeguarding to these networks , otherwise the computer network will be useless , even jeopard the national security 但由于計算機網(wǎng)絡(luò)具有連接形式多樣性、終端分布不均勻性和網(wǎng)絡(luò)的開放性、互連性等特征,致使網(wǎng)絡(luò)易受黑客、駭客、惡意軟件和其它不軌的攻擊,所以網(wǎng)上信息的安全和保密是一個至關(guān)重要的問題。對于軍用的自動化指揮網(wǎng)絡(luò)和銀行等傳輸敏感數(shù)據(jù)的計算機網(wǎng)絡(luò)系統(tǒng)而言,其網(wǎng)上信息的安全和保密尤為重要。因此,上述的網(wǎng)絡(luò)必須有足夠強的安全措施,否則該網(wǎng)絡(luò)將是個無用、甚至會危及國家安全的網(wǎng)絡(luò)。