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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