经典ASP VBScript中的HMAC算法(SHA256) [英] HMAC Algorithm (SHA256) in Classic ASP VBScript
问题描述
我正在尝试使用SHA256作为哈希值在Classic ASP中编写HMAC函数.我以为我做对了，但是 Wikipedia上列出的示例的结果并不相同页.我已经看到了一些通过包含WSC在Classic ASP中使用HMAC SHA256的人的示例.这不是我想做的.
I'm trying to write an HMAC function in Classic ASP using SHA256 as the hash. I thought I got it right, but the results aren't the same for the examples listed on the Wikipedia page. I've seen several examples of people using HMAC SHA256 in Classic ASP by including a WSC. This is not what I want to do.
功能如下:
Public Function HMAC_SHA256(prmKey, prmData)
Dim theKey : theKey = prmKey
Dim Block_Size, O_Pad, I_Pad
Block_Size = 64
O_Pad = 92 'HEX: 5c'
I_Pad = 54 'HEX: 36'
Dim iter, iter2
If Len(theKey) < Block_Size Then
For iter = 1 to Block_Size - Len(theKey)
theKey = theKey & chr(0)
Next
ElseIf Len(theKey) > Block_Size Then
theKey = SHA256(theKey)
End If
Dim o_key_pad : o_key_pad = ""
Dim i_key_pad : i_key_pad = ""
For iter = 1 to Block_Size
o_key_pad = o_key_pad & Chr(Asc(Mid(theKey,iter,1)) xor O_Pad)
i_key_pad = i_key_pad & Chr(Asc(Mid(theKey,iter,1)) xor I_Pad)
Next
HMAC_SHA256 = SHA256(o_key_pad & SHA256(i_key_pad & prmData))
End Function
这是Wikipedia的HMAC的伪代码:
And here's the pseudocode from Wikipedia's HMAC:
function hmac (key, message)
if (length(key) > blocksize) then
key = hash(key) // keys longer than blocksize are shortened
end if
if (length(key) < blocksize) then
key = key ∥ [0x00 * (blocksize - length(key))] // keys shorter than blocksize are zero-padded (where ∥ is concatenation)
end if
o_key_pad = [0x5c * blocksize] ⊕ key // Where blocksize is that of the underlying hash function
i_key_pad = [0x36 * blocksize] ⊕ key // Where ⊕ is exclusive or (XOR)
return hash(o_key_pad ∥ hash(i_key_pad ∥ message)) // Where ∥ is concatenation
end function
我一生无法确定这里出了什么问题.我想有人会告诉我在ASP中这是不可能的，这就是为什么使用WSC的建议如此之多的原因.如果是这样，有人可以解释为什么这不可能吗?我看不到有什么可以使这一切变得不可能.
I can't for the life of me determine what's wrong here. I imagine someone's going to tell me it's impossible in ASP and that's why there are so many suggestions to use the WSC. If this is the case, can someone explain why it's impossible? I don't see anything that should make this impossible.
谢谢！
我已经确定我使用的SHA256函数给出了正确的哈希值，因此与之无关.我还尝试过UCase'ing SHA256函数的结果，并且没有骰子.
I've made sure the SHA256 function I use is giving the correct hashes, so it's nothing to do with that. I've also tried UCase'ing the results of the SHA256 function, and no dice.
从Wiki页面添加了示例.
Added example from wiki page.
推荐答案
好吧，我曾经在经典的ASP中实现TEA(微型加密算法)，但遇到了类似的问题.在我的情况下，根本原因是，ASP将您要串联的字符串再次保存为(& char)为UTF-16，因此偏移量并不总是与我期望的位置匹配.
Well, I once implemented TEA (tiny encryption algorithm) in classic ASP and had similar problems. In my case, the root cause was, that ASP saves the strings you are concatenating (& char) again as UTF-16 and so the offsets did not always match up where I expected them.
我不知道这是否适用于您的用例，因为我必须使用UTF-8特殊字符.
I don't know if this applies to your use case, since I had to work with UTF-8 special characters.
我的解决方案是使用long数组，以便可以使用二进制函数正确地定位.以下是与此数组配合使用的函数，希望它们对您有所帮助.
My solution was to work with an array of longs, that I could target properly with my binary functions. Here are the functions to work with this array, hoping they are helpful for you.
'*******************************************************************************
' getArrayFromInputString (FUNCTION)
'
' PARAMETERS:
' (In) - s_source - Source string (format is defined by n_options)
' (In) - n_blocksize - Blocksize, which is corrected by padding
' (In) - n_options - Options using follobing bits:
' 1: string is in HEX format (e.g. DFD14DAFD9C555C07FEB8F3DA90DEA27)
' RETURN VALUE:
' long array
'
' DESCRIPTION:
' allows to import strings in various formats for all input functions
'*******************************************************************************
private function getArrayFromInputString(s_source, n_blocksize, n_options)
' n_options:
dim a_out, s_padded_string
if (n_options AND 1) = 1 then
s_padded_string = padString(s_source, n_blocksize * 2, "0")
a_out = convertHexStringToArray(s_padded_string)
else
if b_unicode_ then
s_padded_string = padString(s_source, int(n_blocksize / 2), " ")
a_out = convertStringToArray_Unicode(s_padded_string)
else
s_padded_string = padString(s_source, n_blocksize, " ")
a_out = convertStringToArray(s_padded_string)
end if
end if
getArrayFromInputString = a_out
end function
'*******************************************************************************
' convertStringToArray (FUNCTION)
'
' PARAMETERS:
' (In) - s_source - Source string to build the array from
' length MUST be in multiples of 4!
'
' RETURN VALUE:
' Array of type Long - Length is 4 times smaller than the string length
'
' DESCRIPTION:
' Blocks of four characters are calculated into one Long entry of the result array
'*******************************************************************************
private function convertStringToArray(s_source) ' returns long array
dim a_out, n_index, n_length, n_temp
dim n_array_index, n_nibble
n_length = len(s_source)
redim a_out(int(n_length / 4))
for n_index=0 to n_length - 1
n_temp = asc(mid(s_source, n_index + 1, 1))
n_array_index = int(n_index / 4)
n_nibble = n_index MOD 4
a_out(n_array_index) = AddUnsigned(a_out(n_array_index), LShift(n_temp, (3 - n_nibble) * 8))
next
convertStringToArray = a_out
end function
'*******************************************************************************
' convertHexStringToArray (unicode version)
private function convertStringToArray_Unicode(s_source) ' returns long array
dim a_out, n_index, n_length, n_temp
dim n_array_index, n_nibble
n_length = len(s_source)
redim a_out(int(n_length / 2))
for n_index=0 to n_length - 1
n_temp = ascw(mid(s_source, n_index + 1, 1))
n_array_index = int(n_index / 2)
n_nibble = (n_index MOD 2)
a_out(n_array_index) = AddUnsigned(a_out(n_array_index), LShift(n_temp, (1 - n_nibble) * 16))
next
convertStringToArray_Unicode = a_out
end function
'*******************************************************************************
' convertHexStringToArray (FUNCTION)
'
' PARAMETERS:
' (In) - s_source - Source string in hex format, e.g. "EFCE016503CDDB53"
' length MUST be in multiples of 8!
'
' RETURN VALUE:
' Array of type Long - Length is 8 times smaller than the string length
'
' DESCRIPTION:
' Blocks of eight characters are calculated into one Long entry of the result array
'*******************************************************************************
private function convertHexStringToArray(s_source) ' returns long array
dim a_out, n_index, n_length, n_temp
dim n_array_index, n_nibble
n_length = len(s_source)
redim a_out(int(n_length / 8))
for n_index=0 to n_length - 1 step 2
n_temp = CInt("&H" & mid(s_source, n_index + 1, 2))
n_array_index = int(n_index / 8)
n_nibble = int((n_index MOD 8) / 2)
a_out(n_array_index) = AddUnsigned(a_out(n_array_index), LShift(n_temp, (3 - n_nibble) * 8))
next
convertHexStringToArray = a_out
end function
'*******************************************************************************
' padString (FUNCTION)
'
' PARAMETERS:
' (In) - s_source
' (In) - n_blocksize
' (In) - s_padding_char
'
' RETURN VALUE:
' String - padded source string
'
' DESCRIPTION:
' ensure, that the plaintext is multiples of n_blocksize bytes long, the needed amount of s_padding_char is applied
'*******************************************************************************
private function padString(s_source, n_blocksize, s_padding_char)
dim s_out, n_length, n_padding, n_index
s_out = s_source
n_length = len(s_source)
if n_length MOD n_blocksize>0 then
n_padding = n_blocksize - n_length MOD n_blocksize
for n_index=1 to n_padding
s_out = s_out & left(s_padding_char, 1)
next
end if
padString = s_out
end function
'*******************************************************************************
' printArray (FUNCTION)
'
' PARAMETERS:
' (In) - s_prefix - just a string to be written in front for distinction of multiple arrays
' (In) - a_data - long array to print out
'
' RETURN VALUE:
' none
'
' DESCRIPTION:
' debug output function
'*******************************************************************************
private function printArray(s_prefix, a_data)
dim n_index
for n_index=0 to UBound(a_data) - 1
Response.Write "<p>" & s_prefix & a_data(n_index) & " - " & getHex(a_data(n_index)) & "</p>" & vbNewline
next
end function
'*******************************************************************************
' Some more little helper functions
'*******************************************************************************
private function getHex(n_value)
getHex = Right("00000000" & Hex(n_value), 8)
end function
private function getStringFromLong(n_value)
getStringFromLong = _
Chr(RShift(n_value, 24) AND &HFF) & _
Chr(RShift(n_value, 16) AND &HFF) & _
Chr(RShift(n_value, 8) AND &HFF) & _
Chr(n_value AND &HFF)
end function
private function getStringFromLong_Unicode(n_value)
dim s_temp
s_temp = getHex(n_value)
getStringFromLong_Unicode = _
ChrW(int("&H" & mid(s_temp, 1, 4))) & _
ChrW(int("&H" & mid(s_temp, 5, 4)))
end function
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