Sample credentials generation using NodeJS   

/**
 * Get the SkylinkConnectionString
 * @param roomName [Required] Name of the room
 * @param apiKey [Required] API Key
 * @param secret [Required] API secret
 * @param startTime [Required] Room Start Time
 * @param duration [Required] Duration of the room in Hours
 * @returns SkylinkConnectionString to use with the SDK
 */
function getSkylinkConnectionString(roomName, apiKey, secret, startTime, duration) {
    // Get ISO Timestamp of the date
    var dateString = startTime.toISOString();
    // Generate Hmac and URI encode
    var credentials = encodeURIComponent(generateHmac(roomName + "_" + duration + "_" + dateString, secret));
    // Form the connection string
    return apiKey + "/" + roomName + "/" + dateString + "/" + duration + "?cred=" + credentials;
}
/**
 * Get the signature/digest of a supplied input string
 * @param data [Required] The String to encode
 * @param secret [Required] API Secret
 * @returns Str with encoded digest of the input string
 */
function generateHmac(data, secret) {
    var crypto = require("crypto");
    return crypto.createHmac("sha1", secret).update(data).digest("base64");
}

Sample credentials generation using Java

 private static final String TAG = Utils.class.getName();
  private static final String HMAC_SHA1_ALGORITHM = "HmacSHA1";
 
  public static final String TIME_ZONE_UTC = "UTC";
  public static final String ISO_TIME_FORMAT = "yyyy-MM-dd'T'HH:mm:ss.SSSZZZ";
/**
 * Returns the SkylinkConnectionString
 *
 * @param roomName  Name of the room
 * @param apiKey    API Key
 * @param secret    API secret
 * @param startTime Room Start Time
 * @param duration  Duration of the room in Hours
 * @return
 */
public static String getSkylinkConnectionString(String roomName, String apiKey,
                                                String secret,
                                                Date startTime, int duration) {
    Log.d(TAG, "Room name " + roomName);
    Log.d(TAG, "API Key " + apiKey);
    Log.d(TAG, "startTime " + startTime);
    Log.d(TAG, "duration " + duration);
 
    // Convert the date in to ISO format
    String dateString = Utils.getISOTimeStamp(startTime);
    // Compute RFC 2104-compliant HMAC signature
    String cred = calculateRFC2104HMAC(roomName + "_" + duration + "_"
            + dateString, secret);
    try {
        cred = URLEncoder.encode(cred, "UTF-8");
    } catch (UnsupportedEncodingException e) {
        Log.e(TAG, e.getMessage(), e);
    }
    return apiKey + "/"
            + roomName + "/" + dateString + "/" + duration + "?cred="
            + cred;
}
/**
 * Computes RFC 2104-compliant HMAC signature.
 *
 * @param data data The data to be signed.
 * @param key  The signing key.
 * @return The Base64-encoded RFC 2104-compliant HMAC signature.
 */
public static String calculateRFC2104HMAC(String data, String key) {
    String result = null;
    try {
        // Get an hmac_sha1 key from the raw key bytes
        SecretKeySpec signingKey = new SecretKeySpec(key.getBytes(),
                HMAC_SHA1_ALGORITHM);
        // Get an hmac_sha1 Mac instance and initialize with the signing key
        Mac mac = Mac.getInstance(HMAC_SHA1_ALGORITHM);
        mac.init(signingKey);
        // Compute the hmac on input data bytes
        byte[] rawHmac = mac.doFinal(data.getBytes());
        // Base64-encode the hmac
        result = Base64
                .encodeToString(rawHmac, android.util.Base64.DEFAULT);
    } catch (Exception e) {
        Log.e(TAG, "Failed to generate HMAC : " + e.getMessage(), e);
    }
    return result.substring(0, result.length() - 1);
}
 
/**
 * Returns the date in ISO time format
 *
 * @param date
 * @return ISO timestamp
 */
public static String getISOTimeStamp(Date date) {
    TimeZone tz = TimeZone.getTimeZone(TIME_ZONE_UTC);
    DateFormat df = new SimpleDateFormat(ISO_TIME_FORMAT);
    df.setTimeZone(tz);
    return df.format(date);
}

Sample credentials generation using PHP

Thanks to Emil Romanus for this snippet
/* ---------- */
date_default_timezone_set("UTC"); /* or deal manually with possible timezone offsets */
define(SKYLINK_API_SECRET, "xxxxxx");

/* ----------- */

$room_name = "???"
$duration = 24;
$stamp = time(); /* unix timestamp */

$stamp = date("c", $stamp);
$stamp = substr($stamp, 0, -6); /* remove timezone offset, i.e. '+00:00' */
$stamp = $stamp . '.0Z';

$cred_base = $room_name.'_'.sprintf('%.6f', $duration).'_'.$stamp;

$cred = hash_hmac("sha1", $cred_base, SKYLINK_API_SECRET, true);
$cred = base64_encode($cred);

/* ----------- */ 
 

Other articles you may be interested in: Authenticating your Application Key to start a connection