ss="qwertyuiopasdfghjklzxcvbnm"
key="qwertyu"
c=""
a=0
for i in ss:
    if a>len(key)-1:  a=0
    c+=chr(ord(i)+ord(key[a]) )
    a+=1
      
print c

��������������������������

ss = u"qwertyuiopasdfghjklzxcvbnm"
key = u"qwertyu"
c = u""
a = 0

for i in ss:
    if a > len(key)-1:
        a = 0
    c += unichr(ord(i) + ord(key[a]))
    a += 1
      
print c

ss = u"qwertyuiopasdfghjklzxcvbnm"
key = u"qwertyu"
c = u""
a = 0

for i in ss:
    if a > len(key)-1:
        a = 0
    c += unichr(ord(i) + ord(key[a]))
    a += 1

print c

Traceback (most recent call last):
  File "/home/ander/NetBeansProjects/NewPythonProject/src/newpythonproject.py", line 12, in <module>
    print c
UnicodeEncodeError: 'ascii' codec can't encode characters in position 0-25: ordinal not in range(128)

p = unicode(c, 'latin-1 ')

print p