用vb实现DES加解密算法(三)--解密(28) RetS(i * 4 + 1) = (S(i) And &H4) \ &H4 RetS(i * 4 + 2) = (S(i) And &H2) \ &H2 RetS(i * 4 + 3) = (S(i) And &H1) \ &H1 Next For i = 0 To 31 'P变换 CodeP(i) = RetS(P(i)) '产生L10,R10 R10(i) = L9(i) Xor CodeP(i) L10(i) = R9(i) Next '进行第11次迭代 For i = 0 To 47 CodeE(i) = R10(E(i)) '经过E变换扩充,由32位变为48位 CodeE(i) = CodeE(i) Xor K6(i) '与K6按位作不进位加法运算 Next '分8组 For i = 0 To 5 CodeS1(i) = CodeE(i) CodeS2(i) = CodeE(i + 6) CodeS3(i) = CodeE(i + 12) CodeS4(i) = CodeE(i + 18) CodeS5(i) = CodeE(i + 24) CodeS6(i) = CodeE(i + 30) CodeS7(i) = CodeE(i + 36) CodeS8(i) = CodeE(i + 42) Next 'S盒运算,得到8个数