纯代码实现md5算法

小陈 2007-04-05

展开全文

网上已经有C,C++,VB6,java的MD5算法源代码了，甚至已经有了C#的MD5算法代码，唯独VB.NET的MD5算法代码是在是少而又少，因此贴出下列代码供大家雅正。

有人说了，.NET自带MD5算法，何必多此一举呢？如下所示：

    ‘MD5
    Public Shared Function MD5(ByVal strKey As String) As String
        Dim sPwd As String
        Dim bytPwd As [Byte]() = ConStrArr(strKey)
        Dim hashPwd As Byte() = CType(System.Security.Cryptography.CryptoConfig.CreateFromName("MD5"), _
         System.Security.Cryptography.HashAlgorithm).ComputeHash(bytPwd)
        sPwd = BitConverter.ToString(hashPwd)
        sPwd = LCase(sPwd.Replace("-", ""))    ‘去掉中间的"-"符号并转换为小写字母
        Return sPwd
    End Function

    Public Shared Function MD5(ByVal Key As Byte()) As Byte()
        Return CType(System.Security.Cryptography.CryptoConfig.CreateFromName("MD5"), _
         System.Security.Cryptography.HashAlgorithm).ComputeHash(Key)
    End Function

当初写这代码是为了将用了.NET的MD5验证的程序能够用于没有MD5算法的Windows 2000 SP4以下版本，另外也可以更好的了解MD5算法的原理和步骤。

代码如下：

Public Class MD5

Private Const AA As Integer = &H67452301

Private Const BB As Integer = &HEFCDAB89

Private Const CC As Integer = &H98BADCFE

Private Const DD As Integer = &H10325476

Private Const Ts As Long = &H100000000

Private Const S11 As Integer = 7

Private Const S12 As Integer = 12

Private Const S13 As Integer = 17

Private Const S14 As Integer = 22

Private Const S21 As Integer = 5

Private Const S22 As Integer = 9

Private Const S23 As Integer = 14

Private Const S24 As Integer = 20

Private Const S31 As Integer = 4

Private Const S32 As Integer = 11

Private Const S33 As Integer = 16

Private Const S34 As Integer = 23

Private Const S41 As Integer = 6

Private Const S42 As Integer = 10

Private Const S43 As Integer = 15

Private Const S44 As Integer = 21

Private Si As Integer() = New Integer() {}

字节函数

Private Function InitByte(ByRef Data As Byte()) As Byte()

Dim kl As ArrayList = New ArrayList(Data)

Dim dbLength As Int64 = Data.GetLongLength(0)

If dbLength Mod 56 <> 0 OrElse dbLength = 0 Then

Dim i As Integer = 56 - (kl.Count Mod 56) - 1

kl.Add(CByte(&H80)) ‘补1

If i > 0 Then

kl.AddRange(New Byte(i - 1) {}) ‘补0

End If

kl.AddRange(Int64ToBytes(dbLength << 3)) ‘添加长度

Dim buffout As Byte() = kl.ToArray(GetType(Byte))

kl.Clear()

Return buffout

End Function

Private Function InitT() As Int32()

Dim T As Int32() = New Int32(63) {}

For i As Integer = 0 To 63

T(i) = BytesToInt32(Int64ToBytes(CLng(Ts * Math.Abs(Math.Sin(i + 1))) And &HFFFFFFFF&))

Return T

End Function

Private Function InitM(ByRef Data As Byte(), ByVal StartIndex As Long) As Int32()

Dim M As Int32() = New Int32(15) {}

For i As Integer = 0 To 15

M(i) = BytesToInt32(Data, i << 2)

Return M

End Function

Private Function LongAdd(ByVal lngVal1 As Integer, ByVal lngVal2 As Integer) As Integer

Dim lngHighWord As Integer

Dim lngLowWord As Integer

Dim lngOverflow As Integer

lngLowWord = (lngVal1 And &HFFFF&) + (lngVal2 And &HFFFF&)

lngOverflow = lngLowWord 65536

lngHighWord = (((lngVal1 And &HFFFF0000) 65536) + ((lngVal2 And &HFFFF0000) 65536) + lngOverflow) And &HFFFF&

Return lngHighWord << 16 Or (lngLowWord And &HFFFF) ‘LongConversion((lngHighWord * 65536.0#) + (lngLowWord And &HFFFF&))

End Function

Private Function LongAdd4(ByVal lngVal1 As Integer, ByVal lngVal2 As Integer, ByVal lngVal3 As Integer, ByVal lngVal4 As Integer) As Integer

Dim lngHighWord As Integer

Dim lngLowWord As Integer

Dim lngOverflow As Integer

lngLowWord = (lngVal1 And &HFFFF&) + (lngVal2 And &HFFFF&) + (lngVal3 And &HFFFF&) + (lngVal4 And &HFFFF&)

lngOverflow = lngLowWord 65536

lngHighWord = (((lngVal1 And &HFFFF0000) 65536) + ((lngVal2 And &HFFFF0000) 65536) + ((lngVal3 And &HFFFF0000) 65536) + ((lngVal4 And &HFFFF0000) 65536) + lngOverflow) And &HFFFF&

Return lngHighWord << 16 Or (lngLowWord And &HFFFF) ‘LongConversion((lngHighWord * 65536.0#) + (lngLowWord And &HFFFF&))

End Function

‘‘‘ -----------------------------------------------------------------------------

‘‘‘ <summary>

‘‘‘ 循环左移位指令

‘‘‘ </summary>

‘‘‘ <param name="Value"></param>

‘‘‘ <param name="Shift"></param>

‘‘‘ <returns></returns>

‘‘‘ <remarks>

‘‘‘ </remarks>

‘‘‘ <history>

‘‘‘ [malingxian] 2007-1-8 Created

‘‘‘ </history>

‘‘‘ -----------------------------------------------------------------------------

Private Function RoundLeftShift(ByVal Value As Integer, ByVal Shift As Integer) As Integer

Return (Value << Shift) Or ((Value >> (32 - Shift)) And ((2 << (Shift - 1)) - 1))

End Function

‘‘‘ -----------------------------------------------------------------------------

‘‘‘ <summary>

‘‘‘ 循环右移位指令

‘‘‘ </summary>

‘‘‘ <param name="Value"></param>

‘‘‘ <param name="Shift"></param>

‘‘‘ <returns></returns>

‘‘‘ <remarks>

‘‘‘ </remarks>

‘‘‘ <history>

‘‘‘ [malingxian] 2007-1-8 Created

‘‘‘ </history>

‘‘‘ -----------------------------------------------------------------------------

Private Function RoundRightShift(ByVal Value As Integer, ByVal Shift As Integer) As Integer

‘Return (Value << Shift) Or ((Value >> (32 - Shift)) And ((2 << Shift) - 1))

End Function

Private Function F(ByVal x As Integer, ByVal y As Integer, ByVal z As Integer) As Integer

Return (x And y) Or (Not (x) And z)

End Function

Private Function G(ByVal x As Integer, ByVal y As Integer, ByVal z As Integer) As Integer

Return (x And z) Or (y And Not (z))

End Function

Private Function H(ByVal x As Integer, ByVal y As Integer, ByVal z As Integer) As Integer

Return x Xor y Xor z

End Function

Private Function I(ByVal x As Integer, ByVal y As Integer, ByVal z As Integer) As Integer

Return y Xor (x Or Not (z))

End Function

Private Function FF(ByVal a As Integer, ByVal b As Integer, ByVal c As Integer, ByVal d As Integer, ByVal Mj As Integer, ByVal s As Integer, ByVal Ti As Integer) As Integer

Dim pa As Integer = F(b, c, d)

pa = LongAdd4(a, pa, Mj, Ti)

pa = RoundLeftShift(pa, s) ‘注意：此处不是循环移位，故出错

pa = LongAdd(b, pa)

Return pa

Return LongAdd(b, RoundLeftShift(LongAdd4(a, F(b, c, d), Mj, Ti), s))

End Function

Private Function GG(ByVal a As Integer, ByVal b As Integer, ByVal c As Integer, ByVal d As Integer, ByVal Mj As Integer, ByVal s As Integer, ByVal Ti As Integer) As Integer

‘a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s)

‘Return b + ((a + G(b, c, d) + Mj + Ti) << s)

Return LongAdd(b, RoundLeftShift(LongAdd4(a, G(b, c, d), Mj, Ti), s))

End Function

Private Function HH(ByVal a As Integer, ByVal b As Integer, ByVal c As Integer, ByVal d As Integer, ByVal Mj As Integer, ByVal s As Integer, ByVal Ti As Integer) As Integer

‘Return b + ((a + H(b, c, d) + Mj + Ti) << s)

Return LongAdd(b, RoundLeftShift(LongAdd4(a, H(b, c, d), Mj, Ti), s))

End Function

Private Function II(ByVal a As Integer, ByVal b As Integer, ByVal c As Integer, ByVal d As Integer, ByVal Mj As Integer, ByVal s As Integer, ByVal Ti As Integer) As Integer

‘Return b + ((a + (I(b, c, d) + Mj + Ti) << s))

Return LongAdd(b, RoundLeftShift(LongAdd4(a, I(b, c, d), Mj, Ti), s))

End Function

Public Function MD5Conversion(ByVal Data As Byte()) As Byte()

Dim buff As Byte() = Me.InitByte(Data)

‘Dim T As Integer() = InitT()

Dim A As Integer = AA

Dim B As Integer = BB

Dim C As Integer = CC

Dim D As Integer = DD

For i As Integer = 0 To buff.Length - 63 Step 64

Dim M As Integer() = InitM(buff, i)

A = FF(A, B, C, D, M(&H0), S11, &HD76AA478)

D = FF(D, A, B, C, M(&H1), S12, &HE8C7B756)

C = FF(C, D, A, B, M(&H2), S13, &H242070DB)

B = FF(B, C, D, A, M(&H3), S14, &HC1BDCEEE)