PHP script to hash email addresses

emailHasher.php

<?php
$emails = $_POST['emails'];
if($emails) {
  $lines = split("\n", $emails);
  $output = array();
  foreach($lines as $line) {
    $normalized = trim(strtolower($line));
    $crypto = $_POST['crypto'];
    if(!$crypto || $crypto == "md5") {
      $hash = md5($normalized);
    } else if ($crypto == "sha1") {
      $hash = sha1($normalized);
    } else if ($crypto == "sha256") {
      $hash = hash('sha256',$normalized);
    }
    if(strlen($normalized) > 0) {
      $output[] = array("input" => trim($line), "normalized" => $normalized, "modified" => trim($line) !== $normalized , "output" => $hash);
    }
  }
}

if($output && $_POST["format"] === "json") {
  header('Content-Type: text/json');
  print_r(json_encode($output));
  exit;
} else if ($output && $_POST["format"] === "txt") {
  header('Content-Type: text/plain');
  foreach($output as $line) {
    echo $line["output"] . "\n";
  }
  exit;
} else if ($output && $_POST["format"] === "tsv") {
  header('Content-Type: text/plain');
  echo "Input\tNormalized\tHash\n";
  foreach($output as $line) {
    echo $line["input"] . "\t" . $line["normalized"] . "\t" . $line["output"] . "\n";
  }
  exit;
}
?>
<form method="POST">
  <fieldset>
    <legend>Input</legend>
      <textarea name="emails" rows="5"><?php echo $_POST['emails']?></textarea><br/>
  </fieldset>
  <fieldset>
    <legend>Hash type</legend>
    <label><input type="radio" name="crypto" value="md5"> MD5 (default)</label>
    <label><input type="radio" name="crypto" value="sha1"> SHA1</label>
    <label><input type="radio" name="crypto" value="sha256"> SHA256</label>
  </fieldset>
  <fieldset>
    <legend>Output format</legend>
    <label><input type="radio" name="format" value="html" /> HTML Table (default)</label><br/>
    <label><input type="radio" name="format" value="json" /> JSON</label><br/>
    <label><input type="radio" name="format" value="tsv" /> TSV</label><br/>
    <label><input type="radio" name="format" value="txt" /> Plain text (hashes only)</label><br/>
  </fieldset>
  <button type="submit">Submit</button>
</form>
</fieldset>


<?php if($output) { ?>
  <hr/>
<table>
  <thead>
    <tr>
      <td>Input</td>
      <td>Normalized</td>
      <td>Hash</td>
    </tr>
  </thead>
  <tbody>
    <?php foreach($output as $line) { ?>
      <tr>
        <td><?php echo $line["input"]; ?></td>
        <td><?php if($line["modified"]) { echo $line["normalized"]; } ?></td>
        <td><?php echo $line["output"]; ?></td>
      </tr>
    <?php } ?>
  </tbody>
</table>
<?php } ?>