Encryption in code igniter

Encryption

 </pre>  
 this->load->library('encrypt');  
 $enc_username=$this->encrypt->encode($username);  
 $enc_username=str_replace(array('+', '/', '='), array('-', '_', '~'), $enc_username);  
 <pre>  

Decryption

 </pre>  
 $this->load->library('encrypt');  
 $dec_username=str_replace(array('-', '_', '~'), array('+', '/', '='), $enc_username);  
 $dec_username=$this->encrypt->decode($dec_username);  
 <pre>  

For further info
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