一个ASP中的Base64加密 解密函数代码

<% 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,1)) ret = ret & Base64EncMap( (first \ 4) AND 63 ) if (len(plain) MOD 3 ) = 2 then second = asc(mid(plain,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,by4,third,fourth ret = "" by4 = (realLen \ 4) * 4 ndx = 1 do while ndx <= by4 first = Base64DecMap(asc(mid(scrambled,1))) second = Base64DecMap(asc(mid(scrambled,1))) third = Base64DecMap(asc(mid(scrambled,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,1))) ret = ret & chr( ((first * 4) AND 255) + ((second \ 16) AND 3)) if realLen MOD 4 = 3 then third = Base64DecMap(asc(mid(scrambled,1))) ret = ret & chr( ((second * 16) AND 255) + ((third \ 4) AND 15)) end if end if base64Decode = ret END FUNCTION‘ 初始化 call initCodecs‘ 测试代码 dim inp,encode inp = "1234567890" 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%>