Authenticate stream session requests

A stream request registers a session for a livestream event. For details, see Make a stream request

This page covers using HMAC token to authenticate the stream requests.

Before you begin

Before you continue, do the following:

Generate an HMAC token

To generate a token, do the following:

  1. Gather your livestream's asset key and expiration time. For more information, see Enable authentication for requests to create DAI stream sessions

  2. Sort the following parameters alphabetically and separate the parameters with the tilde ~ character:

    event=ASSET_KEY~exp=EXPIRATION

    Replace the following:

    • ASSET_KEY: Required. The livestream event's asset key.
    • EXPIRATION: Required. The expiration timestamp for the token in Unix epoch time.

  3. Calculate a SHA-256 hash of the token string using your DAI authentication key.

  4. Format the hash output in hexadecimal.

  5. To sign the token string, append the signature at the end of the parameters gathered earlier:

    event=...~hmac=HMAC_SIGNATURE

    Replace HMAC_SIGNATURE with the signature you generated by hashing the token string using your DAI authentication key.

  6. To pass the signed token string safely, apply URL-encoding to the signed token string.

The following example signs and encodes a token string that expires within 60 seconds:

# Add 60 seconds to the current time
future_epoch=$((EPOCHSECONDS + 60))

echo "Current: $EPOCHSECONDS"
echo "Future: $future_epoch"
# Current: 1767389133
# Future: 1767389193

# Sample DAI stream authentication key
key="DE0E9..."

# Sort parameters in the token string
token="event=YRB0Bl0oQRCb5J-maPpJUQ~exp=1767389193"

# Generate the token's signature.
echo -n $token | openssl dgst -sha256 -mac HMAC -macopt key:$key
# SHA2-256(stdin)= 9935a013957e5ce893a7ee444d3d452fd0de7d273ff8b65471ddd4619b80d248

# Sign the token: event=YRB0Bl0oQRCb5J-maPpJUQ~exp=1767389193~hmac=9935a013957e5ce893a7ee444d3d452fd0de7d273ff8b65471ddd4619b80d248

# Encode the token: event%3DYRB0Bl0oQRCb5J%2DmaPpJUQ%7Eexp%3D1767389193%7Ehmac%3D9935a013957e5ce893a7ee444d3d452fd0de7d273ff8b65471ddd4619b80d248

Use the HMAC token to request a livestream session

To authenticate your stream create request with an HMAC token, do one of the following:

Authorization request header 

  curl "https://dai.google.com/linear/v1/hls/event/YRB0Bl0oQRCb5J-maPpJUQ/stream" \
  -X POST \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -H "Authorization: DCLKDAI token=event%3DYRB0Bl0oQRCb5J%2DmaPpJUQ%7Eexp%3D1767389193%7Ehmac%3D9935a013957e5ce893a7ee444d3d452fd0de7d273ff8b65471ddd4619b80d248"

Query string parameter 

  curl "https://dai.google.com/linear/v1/hls/event/YRB0Bl0oQRCb5J-maPpJUQ/stream?auth-token=event%3DYRB0Bl0oQRCb5J%2DmaPpJUQ%7Eexp%3D1767389193%7Ehmac%3D9935a013957e5ce893a7ee444d3d452fd0de7d273ff8b65471ddd4619b80d248" \
  -X POST \
  -H "Content-Type: application/x-www-form-urlencoded"

Form data field 

  curl "https://dai.google.com/linear/v1/hls/event/YRB0Bl0oQRCb5J-maPpJUQ/stream" \
  -X POST \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "auth-token=event%3DYRB0Bl0oQRCb5J%2DmaPpJUQ%7Eexp%3D1767389193%7Ehmac%3D9935a013957e5ce893a7ee444d3d452fd0de7d273ff8b65471ddd4619b80d248"

If successful, you see the following JSON response:

  {
  "hls_master_playlist": "https://dai.google.com/linear/hls/pa/event/YRB0Bl0oQRCb5J-maPpJUQ/stream/e91f907e-6a0a-4795-8c96-c8e36e89cbf6:DLS/master.m3u8",
  "media_verification_url": "https://dai.google.com/view/p/service/linear/stream/e91f907e-6a0a-4795-8c96-c8e36e89cbf6:DLS/loc/DLS/network/21775744923/event/YRB0Bl0oQRCb5J-maPpJUQ/media/",
  "metadata_url": "https://dai.google.com/linear/v1/pa/event/YRB0Bl0oQRCb5J-maPpJUQ/stream/e91f907e-6a0a-4795-8c96-c8e36e89cbf6:DLS/metadata",
  "polling_frequency": 10,
  "session_update_url": "https://dai.google.com/linear/v1/pa/event/YRB0Bl0oQRCb5J-maPpJUQ/stream/e91f907e-6a0a-4795-8c96-c8e36e89cbf6:DLS/session",
  "stream_id": "e91f907e-6a0a-4795-8c96-c8e36e89cbf6:DLS",
  "stream_manifest": "https://dai.google.com/linear/hls/pa/event/YRB0Bl0oQRCb5J-maPpJUQ/stream/e91f907e-6a0a-4795-8c96-c8e36e89cbf6:DLS/master.m3u8"
  }

To understand the response structure and status codes, see Method: stream. If authentication fails, you see the following error:

  <!DOCTYPE html>
  <html lang=en>
    <meta charset=utf-8>
    <meta name=viewport content="initial-scale=1, minimum-scale=1, width=device-width">
    <title>Error 401 (Unauthorized)!!1</title>
    ...
    <a href=//www.google.com/><span id=logo aria-label=Google></span></a>
    <p><b>401.</b> <ins>That’s an error.</ins>
    <p><ins>That’s all we know.</ins>