VB.NET实现的MD5加密算法示例【32位】

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 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,z),BigAND(y,BigNOT(z)))
    'tempstr = BigXOR(y,BigAND(z,BigXOR(X,y)))
    w = MD5F(tempstr,rots)
  End Sub
  Sub MD5F3(ByRef w As String,ByVal rots As Integer)
    Dim tempstr As String
    tempstr = BigXOR(BigXOR(X,z)
    'tempstr = BigXOR(X,BigXOR(y,rots)
  End Sub
  Sub MD5F4(ByRef w As String,ByVal rots As Integer)
    Dim tempstr As String
    tempstr = BigXOR(y,BigOR(X,BigNOT(z)))
    w = MD5F(tempstr,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,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,Xin(1),"e8c7b756",12)
      MD5F1(c,Xin(2),"242070db",17)
      MD5F1(b,Xin(3),"c1bdceee",22)
      MD5F1(a,Xin(4),"f57c0faf",Xin(5),"4787c62a",Xin(6),"a8304613",Xin(7),"fd469501",Xin(8),"698098d8",Xin(9),"8b44f7af",Xin(10),"ffff5bb1",Xin(11),"895cd7be",Xin(12),"6b901122",Xin(13),"fd987193",Xin(14),"a679438e",Xin(15),"49b40821",22)
      ' 第二轮循环
      MD5F2(a,"f61e2562",5)
      MD5F2(d,"c040b340",9)
      MD5F2(c,"265e5a51",14)
      MD5F2(b,"e9b6c7aa",20)
      MD5F2(a,"d62f105d","02441453","d8a1e681","e7d3fbc8","21e1cde6","c33707d6","f4d50d87","455a14ed","a9e3e905","fcefa3f8","676f02d9","8d2a4c8a",20)
      ' 第三轮循环
      MD5F3(a,"fffa3942",4)
      MD5F3(d,"8771f681",11)
      MD5F3(c,"6d9d6122",16)
      MD5F3(b,"fde5380c",23)
      MD5F3(a,"a4beea44","4bdecfa9","f6bb4b60","bebfbc70","289b7ec6","eaa127fa","d4ef3085","04881d05","d9d4d039","e6db99e5","1fa27cf8","c4ac5665",23)
      ' 第四轮循环
      MD5F4(a,"f4292244",6)
      MD5F4(d,"432aff97",10)
      MD5F4(c,"ab9423a7",15)
      MD5F4(b,"fc93a039",21)
      MD5F4(a,"655b59c3","8f0ccc92","ffeff47d","85845dd1","6fa87e4f","fe2ce6e0","a3014314","4e0811a1","f7537e82","bd3af235","2ad7d2bb","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$(value2,1))
      valueans = Hex$(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,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,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$(Val("&H" + Mid$(value1,1)) And Val("&H" + Mid$(value2,1)))
    Next loopit
    BigAND = valueans
  End Function
  Function BigNOT(ByVal value1 As String) As String
    Dim valueans As String
    Dim loopit As Integer
    Dim tempstr As String
    value1 = Right$(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$(value1,1)))
    Next loopit
    BigNOT = valueans
  End Function
  Function BigOR(ByVal value1 As String,tempnum As Integer
    tempnum = Len(value1) - Len(value2)
    If tempnum < 0 Then
      valueans = Left$(value2,Math.Abs(tempnum))
      value2 = Mid$(value2,Math.Abs(tempnum) + 1)
    ElseIf tempnum > 0 Then
      valueans = Left$(value1,Math.Abs(tempnum))
      value1 = Mid$(value1,1)) Or Val("&H" + Mid$(value2,1)))
    Next loopit
    BigOR = valueans
  End Function
  Function BigXOR(ByVal value1 As String,1)) Xor Val("&H" + Mid$(value2,1)))
    Next loopit
    BigXOR = Right(valueans,8)
  End Function