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用asp写个加密和解密的类(2)
*************************begin
for icount=1 to lenstring step 3
tempbinary = mid(paramstring, icount, 3)
response.write tempbinary
tempbyteone= asc(mid(tempbinary, 1, 1)): tempsavebitsone=tempbyteone and 3
tempbytetwo = asc(mid(tempbinary, 2, 1)): tempsavebitstwo=tempbytetwo and 15
tempchar = asc(mid(tempbinary, 3, 1))
tempbyteone = mid(sbase_64_characters, ((tempbyteone and 252) 4)+ 1, 1)
tempbytetwo = mid(sbase_64_characters, (((tempbytetwo and 240)16) or (tempsavebitsone * 16) and &hff) + 1, 1)
tempbytethree = mid(sbase_64_characters, (((tempchar and 192)64) or (tempsavebitstwo * 4) and &hff) + 1, 1)
tempbytefour = mid(sbase_64_characters, (tempchar and 63) +1,1)
tempstring = tempbyteone & tempbytetwo &tempbytethree& tempbytefour returnvalue=returnvalue &tempstringnext
*************************end
*************************begin处理最后剩余的几个字符
if mod3string>0 then
tempbinary = mid(paramstring, icount, mod3string)
if mod3string=1 then
tempstring = tempbinary & chr(64) & chr(64) &chr(64)用@号补足位数
else tempstring = tempbinary & chr(64) &chr(64)用@号补足位数
end if
returnvalue=returnvalue & tempstring
end if
*************************end处理最后剩余的几个字符
encode=returnvalue end if end function
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end将ansi编码的字符串进行base64编码
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end将base64编码字符串转换成ansi编码的字符串
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public function decode(paramstring)
tempstring=
returnvalue=
lenstring=len(paramstring)
if lenstring<1 then
decode=returnvalue
else
mod4string=lenstring mod 4
if mod4string >0 then 字符串长度应当是4的倍数
decode=returnvalue
else begin判断是不是@号
if mid(paramstring, lenstring-1, 1) = @ then
mod4string=2
end if
if mid(paramstring, lenstring-2, 1) = @ then
mod4string=1
end if
end判断是不是@号
if mod4string>0 then
lenstring=lenstring-4
******************************begin
for icount=1 to lenstring step 4
tempstring = mid(paramstring, icount, 4)
tempbyteone = instr(sbase_64_characters, mid(tempstring, 1, 1))-1
tempbytetwo = instr(sbase_64_characters, mid(tempstring, 2, 1))-1
tempbytethree = instr(sbase_64_characters, mid(tempstring, 3,1))- 1
tempbytefour = instr(sbase_64_characters, mid(tempstring, 4, 1))-1
tempbyteone = chr(((tempbytetwo and 48) 16) or (tempbyteone *4)and &hff) tempbytetwo = & chr(((tempbytethree and 60)4) or (tempbytetwo * 16) and &hff)
tempbytethree = chr((((tempbytethree and 3) * 64) and &hff)or(tempbytefour and 63))
tempstring=tempbyteone & tempbytetwo & tempbytethree
returnvalue=returnvalue & tempstring
next
******************************end
处理最后剩余的几个字符
if mod4string > 0 then
tempstring=center(center(paramstring,4),mod4string)
returnvalue = returnvalue & tempstring
end if
decode=returnvalue
end if
end if
end function
********************************************
end将base64编码字符串转换成ansi编码的字符串
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作者：csdn pxjianke
