[ENCRYPT & DECRYPT VIDEO FILES]

Large media files, encrypted in your browser — nothing uploaded, no size cap.

Video is the file type where browser-based encryption matters most, because uploading a 4 GB recording to a web service is slow, expensive and hands your footage to someone else. Here the file never moves: it is read from disk in 2 MB chunks, encrypted in memory, and written back out.

Works with any container — MP4, MKV, MOV, AVI, WebM — and with audio files, because encryption operates on raw bytes and does not care about the format.

ENCRYPT_FILE_ONLINE_v1.0.0
🔒 [ENCRYPT] 🔓 [DECRYPT]

[1] SELECT FILE

[2] CHOOSE ENCRYPTION ALGORITHM

[4] ENCRYPT FILE

[WHY VIDEO IS DIFFERENT]

  • No size limit. Chunked processing keeps memory use flat, so a multi-gigabyte file uses no more RAM than a small one. It just takes longer.
  • Do not compress it. Video codecs already compress heavily; running compression again gains nothing and costs time. Leave the compression option off for media.
  • Expect it to take a while. Encryption speed is bounded by how fast your device can read from disk. A 4 GB file is a few minutes, not a few seconds.
  • Keep the tab open. Processing stops if you close or navigate away — there is no server continuing the job in the background.

[AN ENCRYPTED VIDEO WILL NOT PLAY]

This surprises people, so it is worth stating directly. Once encrypted, the file is no longer a video — it is ciphertext. VLC, your phone's gallery and every other player will refuse it, and that is the point.

You must decrypt it back to its original form before it plays. There is no streaming or partial playback of an encrypted file, and renaming it back to .mp4 does not help, because the bytes themselves were transformed rather than merely relabelled.

[WHAT THIS CANNOT DO: DRM]

If your video came from Netflix, Prime Video, Disney+, iTunes, a corporate training platform or a paid course, it is protected by DRM — Widevine, FairPlay or PlayReady — and this tool cannot open it. Nor can any other online decrypter.

DRM is deliberately different from file encryption. The key never reaches you; it is held by a licence server and released only to an approved player on approved hardware, for a limited time. There is no password you could enter here because there is no password at all.

The same applies to HLS and DASH streams whose segments are AES-encrypted: the key sits behind an authenticated licence request, not in the file.

[WHEN ENCRYPTING VIDEO IS GENUINELY USEFUL]

  • Before a cloud backup. Raw footage in Google Drive, Dropbox or Backblaze is readable by anyone who reaches the account.
  • Handing footage to an editor or client on a USB drive or via a file-transfer service.
  • Recordings of private meetings, interviews or medical consultations that must not be readable if the device is lost.
  • Body-cam, dashcam or security footage that may be evidence and needs a tamper-evident chain — the HMAC-SHA256 tag detects any modification.

[HOW TO ENCRYPT OR DECRYPT A VIDEO FILE ONLINE]

Encrypt or decrypt large video files in your browser without uploading them.

  1. Select the video file. Choose your MP4, MKV, MOV, AVI or audio file. There is no size limit — the file is read in 2 MB chunks.
  2. Leave compression off. Video is already compressed, so the compression option gains nothing and only slows the process.
  3. Choose a password or random key. Generate a random 256-bit key for maximum strength, or use a long passphrase.
  4. Wait for processing to finish. Keep the tab open. Speed depends on how fast your device reads from disk, so a multi-gigabyte file takes several minutes.
  5. Decrypt before playing. An encrypted video will not open in any player. Run it back through the tool with the same key to restore a playable file.

[FREQUENTLY ASKED QUESTIONS]

Can I encrypt a large video file online?

Yes, with no size limit. The file is read and encrypted in 2 MB chunks so memory use stays flat regardless of size, and because nothing is uploaded there is no bandwidth cost or transfer time. A multi-gigabyte file works the same way a small one does, just slower.

Why will my encrypted video not play?

Because it is no longer a video file. Encryption transformed every byte, so players find no recognisable container or codec data and refuse to open it. Decrypt it back with the same password or key and it plays normally again.

Can this decrypt a DRM-protected video?

No. DRM systems such as Widevine, FairPlay and PlayReady never give you the key — it is held by a licence server and released only to an approved player. There is no password to enter, so no online tool can decrypt DRM-protected content.

Should I compress a video before encrypting it?

No. Video codecs such as H.264 and H.265 already compress heavily, so a second pass achieves almost nothing while adding significant processing time. Leave compression off for media files. It is worth enabling for text, documents and logs.

Does encrypting reduce video quality?

Not at all. Encryption is lossless and fully reversible — the decrypted file is byte-for-byte identical to the original. Nothing is re-encoded, so resolution, bitrate and colour are untouched.

Can I encrypt audio files the same way?

Yes. MP3, WAV, FLAC, M4A and any other audio format work identically, because encryption operates on raw bytes rather than on the media format.