BitKey Blog
Published in
2 min readOct 17, 2018


BitKey`s Multisig-TimeLock Address


2-of-2 MultiSig-TimeLock address works as a two-factor wallet. One key is on your iPhone (Key1), another key is on your PC/Mac (Key2). With both keys you can sign Bitcoin transaction at any time, this will enhance security and greatly avoids single point risk.

One big advantage is that the Key2 can work as a cold key offline on your PC/Mac, Key2 can be totally airgap and safe. Key2 is kept by HD wallet(BitKey-Multisig-Tool on Mac).

Another advantage is that when your cold key is lost (like a fire disaster destroys the seed-words backup), you can still retrieve your assets with the key1. (After timelock expired, like two years lock time)

2. Software Requirement

  1. iPhone: BitKey App Download from Appstore
  2. Mac: BitKey-Multisig-Tool Download On Mac & Source Code

3. Device Requirement

  1. iPhone
  2. Mac

4. Redeem Script Detail

The Multisig-Timelock script coded as follows:

<public key1> OP_CHECKSIG

Use two keys multi-signatures as unlock script at any time:

<signature key1> <signature key2> OP_FALSE

Use key1 signature as unlocking script when timelock expired:

<signature key1>  OP_TRUE

5. BitKey-Multisig-Tool on Mac, Illustration.

6. Generate Multisig-timeLock Address Steps

Step1. Goto BitKey Settings -> Tap 2-of-2 Multisig-TimeLock Address Cell. On Generate-New-Address page, Set TimeLock.

Step2. Open BitKey-Multisig-Tool on Mac, Select one key pair, tap the QR code button of the public key.(Figure: ❶Public-Key-2 )

Step3. On BitKey Generate-New-Address page, Scan the QR code(❶Public-Key-2) on Mac. Tap Next button to view and save the new Multisig-TimeLock address.

7. Transaction from Multisig-timeLock Address Steps

Step1. On BitKey Transaction Multisig page. Tap the Copy or AirDrop button, This will help your copy or send the Transaction Info(JSON Format) to your Mac.

Step2. On Mac BitKey-Multisig-Tool Input the copied Transaction Info(JSON Format) to the top text field. (Figure: ❷Transaction info(JSON) Input)

Step3. On BitKey, Use the Signature2 QRcode Scan Button to scan the Signature Result on Mac. ( Figure: ❸ Signature Result)

Step4. On BitKey, Tap Next button to get your final data.

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For more information, please visit official website:



BitKey Blog

A pure Bitcoin wallet since 2014. Support: multisig-timelock address and UTXO level transaction tool on iPhone.