[Level 3] How to implement unix password encryption with sha512 in Ubuntu.

#!/usr/bin/env python
import crypt
import re

class shadowPassword:
    def __init__(self, shadow_file = '/etc/shadow'):
        self.shadowFile = shadow_file

    def getPasswordField(self, user):
        fd = open(self.shadowFile, 'r')
        for line in fd.readlines():
            line = line.rstrip()
            match = re.match('^%s:([^:]*):.*$' % user, line)
            if match:
                return match.group(1)
        fd.close()
        return ''

    def setPasswordField(self, user):
        self.password_field = self.getPasswordField(user)
    
    def getPasswordEncryptType(self, password_field=''):
        if self.password_field: password_field = self.password_field
        return password_field.split('$')[1]
    
    def getPasswordSalt(self, password_field=''):
        if self.password_field: password_field = self.password_field
        return password_field.split('$')[2]
    
    def getEncryptPassword(self, password_field=''):
        if self.password_field: password_field = self.password_field
        return password_field.split('$')[3]

class unixPasswordEncryptor:
    def __init__(self, password, type, salt):
        self.password = password
        self.type = type
        self.salt = salt
        pass

    def getPasswordField(self):
        return '$'.join(['', self.getPasswordEncryptType(), self.getPasswordSalt(), self.getEncryptPassword()])

    def getPasswordEncryptType(self):
        return self.type
    
    def getPasswordSalt(self):
        return self.salt   
    
    def getEncryptPassword(self):
        return crypt.crypt(self.password, '$%s$%s' % (self.type, self.salt)).split('$')[3]

if __name__ == '__main__':
        sp = shadowPassword()
        user = 'root'
        password = 'pass'
        sp.setPasswordField(user)
        print 'sp='+sp.getPasswordField(user)
        up = unixPasswordEncryptor(password, sp.getPasswordEncryptType(), sp.getPasswordSalt())
        print 'up='+up.getPasswordField()

output:

sp=$6$.VxhMQ3h$IEjv8jCdueUBLdlz5GPKFSR9YnkYHd2lTSlA5c3ydtN4VeAjFnI0u7jkjtjAk7kPnwKME/skMkELXC35n5Acr0
up=$6$.VxhMQ3h$IEjv8jCdueUBLdlz5GPKFSR9YnkYHd2lTSlA5c3ydtN4VeAjFnI0u7jkjtjAk7kPnwKME/skMkELXC35n5Acr0

Wish this helps.
regards,
Stanley Huang