加密解密字符串的asp函数，如用于ASP链接地址栏参数的加密，看代码就明白。

比如：

show.asp?id=DB26538FA54C70E1E31608CA769087A407E92CF1

Base64解密函数 base64Decode(scrambled)

Base64加密函数 base64Encode(plain)

使用方法：

加密ID：

<a href="show.asp?id=<%=base64Encode(rs("id"))%>" ><%=rs("name")%></a>
解密ID：

id=base64Decode(request("id"))
函数代码：

<%
const BASE_64_MAP_INIT = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
dim newline
dim Base64EncMap(63)
dim Base64DecMap(127)
'初始化函数
PUBLIC SUB initCodecs()
' 初始化变量
newline = "<P>" & chr(13) & chr(10)
dim max, idx
max = len(BASE_64_MAP_INIT)
for idx = 0 to max - 1
Base64EncMap(idx) = mid(BASE_64_MAP_INIT, idx + 1, 1)
next
for idx = 0 to max - 1
Base64DecMap(ASC(Base64EncMap(idx))) = idx
next
END SUB

'Base64加密函数
PUBLIC FUNCTION base64Encode(plain)
if len(plain) = 0 then
base64Encode = ""
exit function
end if
dim ret, ndx, by3, first, second, third
by3 = (len(plain) \ 3) * 3
ndx = 1
do while ndx <= by3
first = asc(mid(plain, ndx+0, 1))
second = asc(mid(plain, ndx+1, 1))
third = asc(mid(plain, ndx+2, 1))
ret = ret & Base64EncMap( (first \ 4) AND 63 )
ret = ret & Base64EncMap( ((first * 16) AND 48) + ((second \ 16) AND 15 ) )
ret = ret & Base64EncMap( ((second * 4) AND 60) + ((third \ 64) AND 3 ) )
ret = ret & Base64EncMap( third AND 63)
ndx = ndx + 3
loop
if by3 < len(plain) then
first = asc(mid(plain, ndx+0, 1))
ret = ret & Base64EncMap( (first \ 4) AND 63 )
if (len(plain) MOD 3 ) = 2 then
second = asc(mid(plain, ndx+1, 1))
ret = ret & Base64EncMap( ((first * 16) AND 48) + ((second \ 16) AND 15 ) )
ret = ret & Base64EncMap( ((second * 4) AND 60) )
else
ret = ret & Base64EncMap( (first * 16) AND 48)
ret = ret '& "="
end if
ret = ret '& "="
end if
base64Encode = ret
END FUNCTION

'Base64解密函数
PUBLIC FUNCTION base64Decode(scrambled)
if len(scrambled) = 0 then
base64Decode = ""
exit function
end if
dim realLen
realLen = len(scrambled)
do while mid(scrambled, realLen, 1) = "="
realLen = realLen - 1
loop
dim ret, ndx, by4, first, second, third, fourth
ret = ""
by4 = (realLen \ 4) * 4
ndx = 1
do while ndx <= by4
first = Base64DecMap(asc(mid(scrambled, ndx+0, 1)))
second = Base64DecMap(asc(mid(scrambled, ndx+1, 1)))
third = Base64DecMap(asc(mid(scrambled, ndx+2, 1)))
fourth = Base64DecMap(asc(mid(scrambled, ndx+3, 1)))
ret = ret & chr( ((first * 4) AND 255) + ((second \ 16) AND 3))
ret = ret & chr( ((second * 16) AND 255) + ((third \ 4) AND 15))
ret = ret & chr( ((third * 64) AND 255) + (fourth AND 63))
ndx = ndx + 4
loop
if ndx < realLen then
first = Base64DecMap(asc(mid(scrambled, ndx+0, 1)))
second = Base64DecMap(asc(mid(scrambled, ndx+1, 1)))
ret = ret & chr( ((first * 4) AND 255) + ((second \ 16) AND 3))
if realLen MOD 4 = 3 then
third = Base64DecMap(asc(mid(scrambled,ndx+2,1)))
ret = ret & chr( ((second * 16) AND 255) + ((third \ 4) AND 15))
end if
end if
base64Decode=ret
END FUNCTION
call initCodecs
'abc="aspxhome.com"
'response.write(base64Encode(abc))'加密字符串abc
'解密加密的字符串
'response.Write(base64Decode(base64Encode(abc)))
%>