[Bitcoin-development] [ANN] Armory 0.92 with Decentralized Multi-sig and Simulfunding

Alan Reiner etotheipi at gmail.com
Wed Jul 30 21:50:22 UTC 2014

Hi Everyone,

The Armory team is pleased to announce the official release of our
decentralized multi-signature interface, called "Lockboxes".  It is a
"true" multi-signature transaction interface:

  * Decentralized multi-sig (no third-party servers or signers needed)
  * Any multi-sig from 1-of-2 up to 7-of-7
  * Any or all of the signing devices can be *offline*
  * All private keys can be generated and managed independently
  * Works with existing Armory wallets
  * Simultaneous funding ("simulfunding") features for escrow and
    contracts (basically CoinJoin)
  * All wrapped up in a nice graphical user interface!

Armory 0.92 includes a GUI for creating, funding and spending from
multi-signature lockboxes, anything from 1-of-2 up to 7-of-7.  All
private keys can be generated independently and never have to be
co-located.    Most importantly, any number of the signing keys can be
created and managed on offline computers!  Also, all transaction and
signature data is communicated directly between parties/devices using
ASCII-armored blocks of text, so no third-party servers/services are
needed (though, in the future, we hope to provide an optional service to
help synchronize the data between parties).

The release also includes the ability to do simultaneous funding
("simulfunding") which is basically CoinJoin through a GUI, but intended
to be used for contracts and escrow.  Each party creates a "promissory
note" (which is basically just a list of UTXOs and a change address),
and those can be merged into a single transaction to be signed by all
funders.  Either all contributions are made simutaneously, or none of
them are.   There is no other outcome.  This means that no trust is
required between the simulfunders.  It is a basic contract enforced by
the bitcoin network itself.

Simulfunding would normally be used in conjuction with multi-signature
lockboxes -- two parties that don't trust each other together create a
lockbox, and then simultaneously fund it (and subsequently spend it)
according to some agreement.  However, it can actually be used to
simulfund any address.  To promote this feature, Armory Technologies Inc
is offering to match up to 20 BTC in donations to the EFF, FSF, College
Crypto Network, Chamber of Digital Commerce, and the Bitcoin Foundation
(and hopefully wikipedia, as a late addition to the list).    We posted
a list of ATI "promissory notes" for matching donations on our
website:   https://bitcoinarmory.com/donation-match-list/

We're very excited about this release, which has been in testing for
over three months, and we've been using for management of company funds
between officers for the last two months.  We have not seen anything
else that comes close to matching the flexibility and security afforded
by it (and without being exceptionally inconvenient!).   See our
tutorials, and especially the FAQ at the end: 

We hope that people will try it out and provide feedback.  Maybe even
match some donations!  We've already matched 3 BTC so far and it was
announced less than 24 hours ago. 


Press Release: 

*VERSION 0.92**
**Released July 29, 2014**

    - *Multi-Signature Lockboxes!*
          Full-featured interface for creating multi-signature addresses,
          putting money into them, and collecting signatures to spend them.
          See our tutorials at:

    - *Simulfunding for Addresses and Lockboxes*
          Use the "Multi-Sig" menu to do prepare simulfunding to any
          arbitrary address.  Or click on the "Simul" checkbox in the
          lockbox manager if you are simulfunding a lockbox.  As a promotion
          for this feature we are matching up to 20 BTC worth donations
          to organizations that support Bitcoin, digital security, online
          freedoms, and open-source software.  See our donation list (with
          instructions): https://bitcoinarmory.com/about/donation-match-list

    - *Improved Mac/OSX Stability*
          We merged a couple Qt4 patches that dramatically improved
          compatibility on OSX 10.7 and newer.  Should work with the
          upcoming release of OSX 10.10.

    - *Armory Daemon/API Upgrades (Beta)*
          The Armory API has been upgraded substantially since version 0.91.
          This version has tons of new functionality matching bitcoind,
          as well as unique functionality including lockbox operations.
          Plan to have complete functionality implemented and tested by
          version 0.93.

    - *Upgraded Transaction History Export to CSV*
          Added running balance reporting for individual and all wallets.
          Also fixed a bug where internal transfers within wallets were
          not being reported properly.

    - *Root PUBLIC Key Export*
          You can now export just the root public key data that allows
          you to reconstruct your watching-only wallet.  It is five lines
          that are easily printed or copied by hand.  Could be used to
          provide someone a chain of addresses for multiple payments.

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