Read Data from Excel in C#

Question

I have an excel file with data as follows
ID     Name     Contact No    Address  
1      ABC        XXXXXXX     ABCNM
2      XYZ        xxxxxxx       ASDFG


Now my requirement is read data from this excel sheet and den encrypt Contact No field for each row and den save data in database,how should it will be done I have to use some ready made available encryption algo for that. Inserting the whole data from excel to database is done bt how to encrypt only Contact No part is a problem. So plz help regarding that.