Chat Hoarding
Lifetime$99

Feature

Decrypts the Crypt15 backup locally

AES-256-GCM decryption with your 64-digit key. msgstore.db.crypt15, the only database WhatsApp writes to the user-accessible backup folder. Keys never leave the Mac.

How the decryption pipeline runs

Your 64-digit hex key is parsed to 32 raw bytes. An HMAC-SHA256-based key derivation (the `encryptionLoop` construction from wa-crypt-tools, with the info string 'backup encryption') derives the AES-256-GCM key. Not standard HKDF; matches WhatsApp's Android client. The Crypt15 protobuf header surfaces the IV (12 or 16 bytes). AES-GCM decrypts and authenticates the ciphertext in one step, so wrong keys produce an authentication tag failure rather than garbled output, and bad keys are caught instantly. The plaintext is gzip-compressed SQLite; Chat Hoarding app gunzips it and writes the raw msgstore.db to a staging folder before bundling into .tarc.

Why this matters

Cloud-based extractors either ship your encrypted backup to their servers or ask you to upload your key. Chat Hoarding app does neither: the 32-byte root key never leaves the Mac process that derives subkeys, never touches a network socket, and is zeroed from memory after the staging write completes. The implementation lives in core-swift/Sources/ChatHoardingCore/Importers/WhatsApp/Crypt15.swift if you want to read it.

What's NOT supported

Crypt12 and Crypt14 are legacy formats. The Mac UI accepts them as input filenames so older users aren't surprised, but no decryption is implemented for them today. If you only have a Crypt12/14 file, restore on the Android phone and let it produce a fresh Crypt15.

FAQ

  • Does Chat Hoarding app store my 64-digit key?

    No. The key lives in process memory only during decryption and is discarded once the decrypted output is written. The result of the decryption (the .tarc archive) is what stays on disk. You only need the 64-digit key when you decrypt a new (or newer) WhatsApp backup; opening an existing .tarc never asks for it again.

  • So the decrypted data is on disk forever?

    Yes, that's the point. The .tarc archive sitting on your Mac is the decrypted database plus media. Today it's plain-text inside the bundle; rely on FileVault for at-rest protection. An age-encrypted .tarc (passphrase + device binding) is on the roadmap for sensitive archives.

  • What happens with a wrong key?

    AES-GCM's authentication tag fails. Chat Hoarding app shows a clear 'wrong key' error rather than a confusing 'corrupt file' message.

Used in

Other capabilities

Save your WhatsApp history forever.

$99 one-time. 2 Macs, revocable. 14-day refund.

Buy lifetime · $99
Decrypts the Crypt15 backup locally · Chat Hoarding