本文实例讲述了VB.NET实现的MD5加密算法。分享给大家供大家参考，具体如下：
Function MD5F(ByVal tempstr As String, ByVal w As String, ByVal X As String, ByVal y As String, ByVal z As String, ByVal Xin As String, ByVal qdata As String, ByVal rots As Integer)
MD5F = BigMod32Add(RotLeft(BigMod32Add(BigMod32Add(w, tempstr), BigMod32Add(Xin, qdata)), rots), X)
End Function
Sub MD5F1(ByRef w As String, ByVal X As String, ByVal y As String, ByVal z As String, ByVal Xin As String, ByVal qdata As String, ByVal rots As Integer)
Dim tempstr As String
tempstr = BigOR(BigAND(X, y), BigAND(BigNOT(X), z))
w = MD5F(tempstr, w, X, y, z, Xin, qdata, rots)
End Sub
Sub MD5F2(ByRef w As String, ByVal X As String, ByVal y As String, ByVal z As String, ByVal Xin As String, ByVal qdata As String, ByVal rots As Integer)
Dim tempstr As String
tempstr = BigOR(BigAND(X, z), BigAND(y, BigNOT(z)))
'tempstr = BigXOR(y, BigAND(z, BigXOR(X, y)))
w = MD5F(tempstr, w, X, y, z, Xin, qdata, rots)
End Sub
Sub MD5F3(ByRef w As String, ByVal X As String, ByVal y As String, ByVal z As String, ByVal Xin As String, ByVal qdata As String, ByVal rots As Integer)
Dim tempstr As String
tempstr = BigXOR(BigXOR(X, y), z)
'tempstr = BigXOR(X, BigXOR(y, z))
w = MD5F(tempstr, w, X, y, z, Xin, qdata, rots)
End Sub
Sub MD5F4(ByRef w As String, ByVal X As String, ByVal y As String, ByVal z As String, ByVal Xin As String, ByVal qdata As String, ByVal rots As Integer)
Dim tempstr As String
tempstr = BigXOR(y, BigOR(X, BigNOT(z)))
w = MD5F(tempstr, w, X, y, z, Xin, qdata, rots)
End Sub
Function MD5_Calc(ByVal hashthis As String) As String
Dim buf(4) As String
Dim Xin(16) As String
Dim tempnum As Integer, tempnum2 As Integer, loopit As Integer, loopouter As Integer, loopinner As Integer
Dim a As String, b As String, c As String, d As String, tempstr99 As String
tempnum = 8 * Len(hashthis)
hashthis = hashthis + Chr(128) 'Add binary 10000000
tempnum2 = 56 - Len(hashthis) Mod 64
If tempnum2 < 0 Then
tempnum2 = 64 + tempnum2
End If
'hashthis = hashthis + String(tempnum2, Chr(0))
For loopit = 1 To tempnum2
hashthis = hashthis + Chr(0)
Next loopit
For loopit = 1 To 8
hashthis = hashthis + Chr(tempnum Mod 256)
tempnum = tempnum - tempnum Mod 256
tempnum = tempnum / 256
Next loopit
buf(0) = "67452301"
buf(1) = "efcdab89"
buf(2) = "98badcfe"
buf(3) = "10325476"
For loopouter = 0 To (Len(hashthis) / 64 - 1)
a = buf(0)
b = buf(1)
c = buf(2)
d = buf(3)
' Get the 512 bits
For loopit = 0 To 15
Xin(loopit) = ""
For loopinner = 1 To 4
'tempstr99 = Hex$(Asc(Mid$(hashthis, 64 * loopouter + 4 * loopit + loopinner, 1)))
'If Len(tempstr99) < 2 Then tempstr99 = "0" + tempstr99
'Xin(loopit) = Xin(loopit) + tempstr99
Xin(loopit) = Hex$(Asc(Mid$(hashthis, 64 * loopouter + 4 * loopit + loopinner, 1))) + Xin(loopit)
If Len(Xin(loopit)) Mod 2 Then Xin(loopit) = "0" + Xin(loopit)
Next loopinner
Next loopit
' 第一轮循环
MD5F1(a, b, c, d, Xin(0), "d76aa478", 7)
MD5F1(d, a, b, c, Xin(1), "e8c7b756", 12)
MD5F1(c, d, a, b, Xin(2), "242070db", 17)
MD5F1(b, c, d, a, Xin(3), "c1bdceee", 22)
MD5F1(a, b, c, d, Xin(4), "f57c0faf", 7)
MD5F1(d, a, b, c, Xin(5), "4787c62a", 12)
MD5F1(c, d, a, b, Xin(6), "a8304613", 17)
MD5F1(b, c, d, a, Xin(7), "fd469501", 22)
MD5F1(a, b, c, d, Xin(8), "698098d8", 7)
MD5F1(d, a, b, c, Xin(9), "8b44f7af", 12)
MD5F1(c, d, a, b, Xin(10), "ffff5bb1", 17)
MD5F1(b, c, d, a, Xin(11), "895cd7be", 22)
MD5F1(a, b, c, d, Xin(12), "6b901122", 7)
MD5F1(d, a, b, c, Xin(13), "fd987193", 12)
MD5F1(c, d, a, b, Xin(14), "a679438e", 17)
MD5F1(b, c, d, a, Xin(15), "49b40821", 22)
' 第二轮循环
MD5F2(a, b, c, d, Xin(1), "f61e2562", 5)
MD5F2(d, a, b, c, Xin(6), "c040b340", 9)
MD5F2(c, d, a, b, Xin(11), "265e5a51", 14)
MD5F2(b, c, d, a, Xin(0), "e9b6c7aa", 20)
MD5F2(a, b, c, d, Xin(5), "d62f105d", 5)
MD5F2(d, a, b, c, Xin(10), "02441453", 9)
MD5F2(c, d, a, b, Xin(15), "d8a1e681", 14)
MD5F2(b, c, d, a, Xin(4), "e7d3fbc8", 20)
MD5F2(a, b, c, d, Xin(9), "21e1cde6", 5)
MD5F2(d, a, b, c, Xin(14), "c33707d6", 9)
MD5F2(c, d, a, b, Xin(3), "f4d50d87", 14)
MD5F2(b, c, d, a, Xin(8), "455a14ed", 20)
MD5F2(a, b, c, d, Xin(13), "a9e3e905", 5)
MD5F2(d, a, b, c, Xin(2), "fcefa3f8", 9)
MD5F2(c, d, a, b, Xin(7), "676f02d9", 14)
MD5F2(b, c, d, a, Xin(12), "8d2a4c8a", 20)
' 第三轮循环
MD5F3(a, b, c, d, Xin(5), "fffa3942", 4)
MD5F3(d, a, b, c, Xin(8), "8771f681", 11)
MD5F3(c, d, a, b, Xin(11), "6d9d6122", 16)
MD5F3(b, c, d, a, Xin(14), "fde5380c", 23)
MD5F3(a, b, c, d, Xin(1), "a4beea44", 4)
MD5F3(d, a, b, c, Xin(4), "4bdecfa9", 11)
MD5F3(c, d, a, b, Xin(7), "f6bb4b60", 16)
MD5F3(b, c, d, a, Xin(10), "bebfbc70", 23)
MD5F3(a, b, c, d, Xin(13), "289b7ec6", 4)
MD5F3(d, a, b, c, Xin(0), "eaa127fa", 11)
MD5F3(c, d, a, b, Xin(3), "d4ef3085", 16)
MD5F3(b, c, d, a, Xin(6), "04881d05", 23)
MD5F3(a, b, c, d, Xin(9), "d9d4d039", 4)
MD5F3(d, a, b, c, Xin(12), "e6db99e5", 11)
MD5F3(c, d, a, b, Xin(15), "1fa27cf8", 16)
MD5F3(b, c, d, a, Xin(2), "c4ac5665", 23)
' 第四轮循环
MD5F4(a, b, c, d, Xin(0), "f4292244", 6)
MD5F4(d, a, b, c, Xin(7), "432aff97", 10)
MD5F4(c, d, a, b, Xin(14), "ab9423a7", 15)
MD5F4(b, c, d, a, Xin(5), "fc93a039", 21)
MD5F4(a, b, c, d, Xin(12), "655b59c3", 6)
MD5F4(d, a, b, c, Xin(3), "8f0ccc92", 10)
MD5F4(c, d, a, b, Xin(10), "ffeff47d", 15)
MD5F4(b, c, d, a, Xin(1), "85845dd1", 21)
MD5F4(a, b, c, d, Xin(8), "6fa87e4f", 6)
MD5F4(d, a, b, c, Xin(15), "fe2ce6e0", 10)
MD5F4(c, d, a, b, Xin(6), "a3014314", 15)
MD5F4(b, c, d, a, Xin(13), "4e0811a1", 21)
MD5F4(a, b, c, d, Xin(4), "f7537e82", 6)
MD5F4(d, a, b, c, Xin(11), "bd3af235", 10)
MD5F4(c, d, a, b, Xin(2), "2ad7d2bb", 15)
MD5F4(b, c, d, a, Xin(9), "eb86d391", 21)
buf(0) = BigAdd(buf(0), a)
buf(1) = BigAdd(buf(1), b)
buf(2) = BigAdd(buf(2), c)
buf(3) = BigAdd(buf(3), d)
Next loopouter
hashthis = ""
For loopit = 0 To 3
For loopinner = 3 To 0 Step -1
hashthis = hashthis + Mid(buf(loopit), 1 + 2 * loopinner, 2)
Next loopinner
Next loopit
MD5_Calc = hashthis
End Function
Function BigMod32Add(ByVal value1 As String, ByVal value2 As String) As String
BigMod32Add = Right$(BigAdd(value1, value2), 8)
End Function
Public Function BigAdd(ByVal value1 As String, ByVal value2 As String) As String
Dim valueans As String
Dim loopit As Integer, tempnum As Integer
tempnum = Len(value1) - Len(value2)
If tempnum < 0 Then
value1 = Space$(Math.Abs(tempnum)) + value1
ElseIf tempnum > 0 Then
value2 = Space$(Math.Abs(tempnum)) + value2
End If
tempnum = 0
For loopit = Len(value1) To 1 Step -1
tempnum = tempnum + Val("&H" + Mid$(value1, loopit, 1)) + Val("&H" + Mid$(value2, loopit, 1))
valueans = Hex$(tempnum Mod 16) + valueans
tempnum = Int(tempnum / 16)
Next loopit
If tempnum <> 0 Then
valueans = Hex$(tempnum) + valueans
End If
BigAdd = Right(valueans, 8)
End Function
Public Function RotLeft(ByVal value1 As String, ByVal rots As Integer) As String
Dim tempstr As String
Dim loopit As Integer, loopinner As Integer
Dim tempnum As Integer
rots = rots Mod 32
If rots = 0 Then
RotLeft = value1
Exit Function
End If
value1 = Right$(value1, 8)
'tempstr = String$(8 - Len(value1), "0") + value1
For loopit = 1 To 8 - Len(value1)
tempstr = tempstr + "0"
Next loopit
tempstr = tempstr + value1
value1 = ""
' 转换成二进制形式
For loopit = 1 To 8
tempnum = Val("&H" + Mid$(tempstr, loopit, 1))
For loopinner = 3 To 0 Step -1
If tempnum And 2 ^ loopinner Then
value1 = value1 + "1"
Else
value1 = value1 + "0"
End If
Next loopinner
Next loopit
tempstr = Mid$(value1, rots + 1) + Left$(value1, rots)
' 转换为十六进制
value1 = ""
For loopit = 0 To 7
tempnum = 0
For loopinner = 0 To 3
If Val(Mid$(tempstr, 4 * loopit + loopinner + 1, 1)) Then
tempnum = tempnum + 2 ^ (3 - loopinner)
End If
Next loopinner
value1 = value1 + Hex$(tempnum)
Next loopit
RotLeft = Right(value1, 8)
End Function
Function BigAND(ByVal value1 As String, ByVal value2 As String) As String
Dim valueans As String
Dim loopit As Integer, tempnum As Integer
tempnum = Len(value1) - Len(value2)
If tempnum < 0 Then
value2 = Mid$(value2, Math.Abs(tempnum) + 1)
ElseIf tempnum > 0 Then
value1 = Mid$(value1, tempnum + 1)
End If
For loopit = 1 To Len(value1)
valueans = valueans + Hex$(Val("&H" + Mid$(value1, loopit, 1)) And Val("&H" + Mid$(value2, loopit, 1)))
Next loopit
BigAND = valueans
End Function
Function BigNOT(ByVal value1 As String) As String
Dim valueans As String
Dim loopit As Integer
Dim tempstr As String
value1 = Right$(value1, 8)
'value1 = String$(8 - Len(value1), "0") + value1
For loopit = 1 To 8 - Len(value1)
tempstr = tempstr + "0"
Next loopit
tempstr = tempstr + value1
value1 = tempstr
For loopit = 1 To 8
valueans = valueans + Hex$(15 Xor Val("&H" + Mid$(value1, loopit, 1)))
Next loopit
BigNOT = valueans
End Function
Function BigOR(ByVal value1 As String, ByVal value2 As String) As String
Dim valueans As String
Dim loopit As Integer, tempnum As Integer
tempnum = Len(value1) - Len(value2)
If tempnum < 0 Then
valueans = Left$(value2, Math.Abs(tempnum))
value2 = Mid$(value2, Math.Abs(tempnum) + 1)
ElseIf tempnum > 0 Then
valueans = Left$(value1, Math.Abs(tempnum))
value1 = Mid$(value1, tempnum + 1)
End If
For loopit = 1 To Len(value1)
valueans = valueans + Hex$(Val("&H" + Mid$(value1, loopit, 1)) Or Val("&H" + Mid$(value2, loopit, 1)))
Next loopit
BigOR = valueans
End Function
Function BigXOR(ByVal value1 As String, ByVal value2 As String) As String
Dim valueans As String
Dim loopit As Integer, tempnum As Integer
tempnum = Len(value1) - Len(value2)
If tempnum < 0 Then
valueans = Left$(value2, Math.Abs(tempnum))
value2 = Mid$(value2, Math.Abs(tempnum) + 1)
ElseIf tempnum > 0 Then
valueans = Left$(value1, Math.Abs(tempnum))
value1 = Mid$(value1, tempnum + 1)
End If
For loopit = 1 To Len(value1)
valueans = valueans + Hex$(Val("&H" + Mid$(value1, loopit, 1)) Xor Val("&H" + Mid$(value2, loopit, 1)))
Next loopit
BigXOR = Right(valueans, 8)
End Function
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