<p>Can <a href="http://en.wikipedia.org/wiki/Unicode" rel="noreferrer">Unicode</a> characters be encoded and decoded with <a href="http://en.wikipedia.org/wiki/Base64" rel="noreferrer">Base64</a>?</p>

<p>I have attempted to encode the string 'الله', but when I decoded it all I got was '????'.</p>

Of course they can. It depends on how your language or Base64 routine handles Unicode input. For example, Python's
```
b64
```
routines expect an encoded string (as Base64 encodes binary to text, not Unicode codepoints to text).
```
```
Python 2.5.1 (r251:54863, Jul 31 2008, 22:53:39)
[GCC 4.1.2 (Ubuntu 4.1.2-0ubuntu4)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> a = 'ûñö'
>>> import base64
>>> base64.b64encode(a)
'w7vDscO2'
>>> base64.b64decode('w7vDscO2')
'\xc3\xbb\xc3\xb1\xc3\xb6'
>>> print '\xc3\xbb\xc3\xb1\xc3\xb6'
ûñö
>>>     
>>> u'üñô'
u'\xfc\xf1\xf4'
>>> base64.b64encode(u'\xfc\xf1\xf4')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.5/base64.py", line 53, in b64encode
    encoded = binascii.b2a_base64(s)[:-1]
UnicodeEncodeError: 'ascii' codec can't encode characters in position
0-2: ordinal not in range(128)
>>> base64.b64encode(u'\xfc\xf1\xf4'.encode('utf-8'))
'w7zDscO0'
>>> base64.b64decode('w7zDscO0')
'\xc3\xbc\xc3\xb1\xc3\xb4'
>>> print base64.b64decode('w7zDscO0')
üñô
>>> a = 'الله'
>>> a
'\xd8\xa7\xd9\x84\xd9\x84\xd9\x87'
>>> base64.b64encode(a)
'2KfZhNmE2Yc='
>>> b = base64.b64encode(a)
>>> print base64.b64decode(b)
الله
```
```