VB VBA ASP 可通用的基于Base64进行加密和解密的函数

可用于Access VBA 以及 Excel VBA对字符串 数据甚至文本文件进行加密和解密，以保证您数据的安全。

先创建一个模块，在模块中添加如下代码

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 =vbCrlf ' 如果是ASP就改成这个 "

" & 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

' 初始化

call initCodecs

' 测试代码

dim inp, encode

inp = "1234567890"

encode = base64Encode(inp)

Debug.Print "加密前为:" & inp & vbCrlf

Debug.Print "加密后为:" & encode & vbCrlf

Debug.Print "解密后为:" & base64Decode(encode) & vbCrlf