Fonction SHA1 en ASP

Le SHA1 : http://www.itl.nist.gov/fipspubs/fip180-1.htm

Original : http://p2p.wrox.com/archive/proasp_howto/2002-02/27.asp

<%
function tohex(value)
value = clng(value)
tohex = lcase(hex(value))
do while len(tohex) < 8
tohex = "0" & tohex
loop
end function

function tobin(value)
dim hexstr
hexstr = tohex(value)
tobin = ""
for i = 1 to len(hexstr)
select case mid(hexstr, i, 1)
case "f", "F"
tobin = tobin & "1111"
case "e", "E"
tobin = tobin & "1110"
case "d", "D"
tobin = tobin & "1101"
case "c", "C"
tobin = tobin & "1100"
case "b", "B"
tobin = tobin & "1011"
case "a", "A"
tobin = tobin & "1010"
case "9"
tobin = tobin & "1001"
case "8"
tobin = tobin & "1000"
case "7"
tobin = tobin & "0111"
case "6"
tobin = tobin & "0110"
case "5"
tobin = tobin & "0101"
case "4"
tobin = tobin & "0100"
case "3"
tobin = tobin & "0011"
case "2"
tobin = tobin & "0010"
case "1"
tobin = tobin & "0001"
case else
tobin = tobin & "0000"
end select
next
end function

function bin2dec(binstr)
dim flip
flip = false
bin2dec = clng(0)
if left(binstr,1) = "0" then
for i = 1 to len(binstr)
if mid(binstr,33-i,1)="1" then
bin2dec = bin2dec + (2^(i-1))
end if
next
else
for i = 1 to len(binstr)
if flip then
if mid(binstr,33-i,1)="0" then
bin2dec = bin2dec - (2^(i-1))
end if
else
if mid(binstr,33-i,1)="1" then
bin2dec = bin2dec - (2^(i-1))
flip = true
end if
end if
next
end if
end function

function rshift(value,count)
dim binstr
if count >= 32 then
binstr = ""
elseif count > 0 then
binstr = left(tobin(value), 32-count)
else
binstr = tobin(value)
end if
do while len(binstr) < 32
binstr = "0" + binstr
loop
rshift = bin2dec(binstr)
end function

function lshift(value,count)
dim binstr
if count >= 32 then
binstr = ""
elseif count > 0 then
binstr = right(tobin(value), 32-count)
else
binstr = tobin(value)
end if
do while len(binstr) < 32
binstr = binstr + "0"
loop
lshift = bin2dec(binstr)
end function

function rol(value,count)
rol = lshift(value,count) or rshift(value,32-count)
end function

function add32(a, b)
dim bina, binb, total, result, carry
bina = tobin(a)
binb = tobin(b)
result = ""
carry = "0"
for i = 1 to 32
total = 0
if mid(bina,33-i,1)="1" then total = total + 1
if mid(binb,33-i,1)="1" then total = total + 1
if carry="1" then total = total + 1
select case total
case 3
carry = "1"
result = "1" + result
case 2
carry = "1"
result = "0" + result
case 1
carry = "0"
result = "1" + result
case else
carry = "0"
result = "0" + result
end select
next
add32 = bin2dec(result)
end function

function f(b,c,d,t)
if t < 20 then
f = (b and c) or ((not b) and d)
elseif t < 40 then
f = b xor c xor d
elseif t < 60 then
f = (b and c) or (b and d) or (c and d)
else
f = b xor c xor d
end if
end function

function k(t)
if t < 20 then
k = clng(1518500249)
elseif t < 40 then
k = clng(1859775393)
elseif t < 60 then
k = clng(-1894007588)
else
k = clng(-899497514)
end if
end function

function pad(message)
dim l, n
l = len(message)
n = (((l+8) \ 64) + 1)*16
redim m(n-1)
for i = 0 to n-1
m(i) = clng(0)
next
for i = 0 to l-1
m(i\4) = m(i\4) or lshift(asc(mid(message,i+1,1)),(24-(i mod 4)*8))
next
m(l\4) = m(l\4) or lshift(clng(128),(24-(l mod 4)*8))
m(n-1) = l*8
pad = m
end function

function sha1(message)
dim h0, h1, h2, h3, h4
dim a, b, c, d, e, temp
dim l, n
dim w(79)

l = len(message)
n = (((l+8) \ 64) + 1)*16
m = pad(message)

h0 = clng(1732584193)
h1 = clng(-271733879)
h2 = clng(-1732584194)
h3 = clng(271733878)
h4 = clng(-1009589776)

for block = 0 to n-1 step 16
a = h0
b = h1
c = h2
d = h3
e = h4
for t = 0 to 79
if t < 16 then
w(t) = m(block + t)
else
w(t) = rol(w(t-3) xor w(t-8) xor w(t-14) xor w(t-16),1)
end if
temp = add32(rol(a,5),add32(f(b,c,d,t),add32(e,add32(w(t),k(t)))))
e = d
d = c
c = rol(b,30)
b = a
a = temp
next
h0 = add32(h0, a)
h1 = add32(h1, b)
h2 = add32(h2, c)
h3 = add32(h3, d)
h4 = add32(h4, e)
next
sha1 = tohex(h0)+tohex(h1)+tohex(h2)+tohex(h3)+tohex(h4)
end function
%>

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