分享 ASP的Base64加密解密函数

建议做成一个include包含文件，包含核心代码：

<%

OPTION EXPLICIT
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

%>

asp版本base64加密解密调用：

' 初始化
call initCodecs
' 测试代码
dim inp, encode
inp = "yizuotu.net"
encode = base64Encode(inp)
response.write "加密前为:" & inp & newline
response.write "加密后为:" & encode & newline
response.write "解密后为:" & base64Decode(encode) & newline