Instead of calling the same function twice - php

Question

I'm first checking if a function returns a valid result, and then, if the result is valid, I need to use that in my script. But instead of checking once, and then coming back again to the function for its result, is there a way to do it all in one go? Here, $strVal is the variable I need to use in an querystring later.
$conn = connect();
encrypt('HIs#$%.-','x');
decrypt('6507A27EB0521AFA0776F1A4F8033041','x');
//If the function returns a valid result,
if (encrypt('Tom','x'))
{
echo 'Success'.$strVal;//I'll use this in a querystring later.
}
else
{
echo 'An error occurred';
}
//Encrypt string
function encrypt($strToEncrypt,$salt)
{
global $conn;
$elements = $conn->prepare("select hex(aes_encrypt(:what,:salt)) as encValue");
$elements->bindParam(':what', $strToEncrypt);
$elements->bindParam(':salt', $salt);
$elements->execute();
$row = $elements->fetch();
$strVal = $row['encValue'];
if(is_null($strVal)){return false;}else{return $strVal;}
}
//Decrypt string
function decrypt($strToDecrypt,$salt)
{
global $conn;
$elements = $conn->prepare("select aes_decrypt(unhex(:what),:salt) as decValue");
$elements->bindParam(':what', $strToDecrypt);
$elements->bindParam(':salt', $salt);
$elements->execute();
$row = $elements->fetch();
if(is_null($row['decValue']))
{echo "Null";}else{echo $row['decValue'];}
}

Answer 1

Yes, you could do the variable assignment inside the condition:
/* single 'equal' operator intended */
if( $strVal = encrypt( 'Tom', 'x' ) )
{
echo 'Success' . $strVal;
}