(1)将该字符的ASCII码转换成对应的8位二进制;
(2)将对应的8位二进制数进行按位取反(1变0,0变1);
(3)将产生的8位二进制数循环左移2次;
图a
(4)将最后产生的8位二进制数转换成对应的十六进制数。
例如,密文小写字母“d”通过上述解密算法解密后生成的明文是“6E”,信息加密过程如图b所示。
图b
实现上述功能的VB程序如下:在文本框Text1中输入密文,单击“解密”按钮Command1,程序对密文数据依次进行解密处理,在文本框Text2中显示解密后生成的明文。程序运行界面如图c所示。
图c
实现上述功能的VB程序如下,请问答下列问题:
(1)如果输入密文为小写字母“a”,则解密后得到的明文是 ______________。
(2)请在划线处填入合适代码。
Function jiemi(m As String) As String '将4位二进制数转换成相应的十六进制数
Dim k As Integer, i As Integer
Dim str As String
str = "0123456789ABCDEF"
k = 0
For i = 1 To 4
k = k * 2 + Val(Mid(m, i, 1))
Next i①_______
End Function
Private Sub Command1_Click()
Dim ans As String, s As String, ch As String, ret As String
Dim s1 As String, s2 As String
Dim i As Integer, m As Integer, asc1 As Integer, n As Integer
s = Text1.Text
ans = ""
For i = 1 To Len(s)
ch = Mid(s, i, 1) '取出第i个字符存入变量ch
asc1 = Asc(ch)
ret = ""
For m = 1 To 8 '完成解密步骤(1)和步骤(2)
②______
ret = n & ret
asc1 = asc1 \ 2
Next m
ret = Mid(ret, 3, 6) + Mid(ret, 1, 2) '完成解密步骤(3)
s1 = jiemi(Mid(ret, 1, 4))
③_________
ans = ans& s1 & s2 '将第i个解密后的字符添加到变量ans的末尾
Next i
Text2.Text = ans
End Sub
同类型试题
y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2