What is the best way to encrypt information after login on the website?

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PHP

HTML5

I want to encrypt password, email, username and other information after the user logins on the site, encrypt them in the cookies. I new to php

This my php for password encryption and decryption.

I m a newbie to php. If you have better way than mine please tell me where to improve.

function encryptionKey($password) {
    $password = strtolower($password);
    return array(hash("sha256", $password));
	}
	function encrypt($enpassword) {
		
			return  trim( base64_encode( mcrypt_encrypt( MCRYPT_RIJNDAEL_256, substr($enpassword[0],0,32),$enpassword, MCRYPT_MODE_CBC, substr($enpassword[1],0,32) )));
    }
	function decrypt($depassword) {
            return mcrypt_decrypt(MCRYPT_RIJNDAEL_256, substr($depassword[0],0,32), base64_decode($depassword),MCRYPT_MODE_CBC, substr($depassword[1],0,32)
        );
	} 	
	
public function hashPassword($password) {
	$saltpassword = $password . "5138hyh8g0ghg3g5h"; 		
	$encpassword = hash('sha256', $saltpassword);
		return $encpassword;
}