Subject: Re: [bitcoin-dev] Proposal: Bitcoin Secure Multisig Setup

From: Hugo Nguyen <[email-masked]>
Date: Mon, 5 Apr 2021 00:02:45 -0700

Hi all,

Please find below the complete draft of the Bitcoin Secure Multisig Setup
(BSMS) BIP. The spec has gone through a number of important updates in the
last month or so. Thanks everyone who has participated in the review
process.

As a PR: https://github.com/bitcoin/bips/pull/1097

A few notes:
* PBKDF2-SHA512 was chosen instead of PBKDF2-SHA256 for the key derivation
function, due to widespread existing hardware support for PBKDF2-SHA512
* Only one descriptor is stored in the multisig configuration - this
simplifies wallet setup and recovery
(For the full review and relevant discussions, please check out
https://github.com/nunchuk-io/bips/pull/1).

Best,
Hugo

<pre>
  BIP: To be determined
  Layer: Applications
  Title: Bitcoin Secure Multisig Setup (BSMS)
  Author: Hugo Nguyen <hugo at nunchuk.io>, Peter Gray <peter at
coinkite.com>, Marko Bencun <marko at shiftcrypto.ch>, Aaron Chen
<aarondongchen at gmail.com>, Rodolfo Novak <rodolfo at coinkite.com>
  Comments-Summary: No comments yet.
  Comments-URI:
  Status: Proposed
  Type: Standards Track
  Created: 2020-11-10
  License: BSD-2-Clause
</pre>

==Introduction==

===Abstract===

This document proposes a mechanism to set up multisig wallets securely.

===Copyright===

This BIP is licensed under the 2-clause BSD license.

===Motivation===

The Bitcoin multisig experience has been greatly streamlined under
[https://github.com/bitcoin/bips/blob/master/bip-0174.mediawiki
BIP-0174
(Partially Signed Bitcoin Transaction)]. However, what is still
missing is a standardized process for setting up multisig wallets
securely across different vendors.

There are a number of concerns when it comes to setting up a multisig wallet:

# Whether the multisig configuration, such as Signer membership,
script type, derivation paths and number of signatures required, is
correct and not tampered with.
# Whether the keys or the multisig configuration are leaked during the setup.
# Whether the Signer persists the multisig configuration in their
respective storage, and under what format.
# Whether the Signer's storage is tamper-proof.
# Whether the Signer subsequently uses the multisig configuration to
generate and verify receive and change addresses.

An attacker who can modify the multisig configuration can steal or
hold funds for ransom by duping the user into sending funds to the
wrong address. An attacker who cannot modify the configuration but can
learn about the keys and/or the configuration can monitor transactions
in the wallet, resulting in loss of privacy.

This proposal seeks to address concerns #1, #2 and #3: to mitigate the
risk of tampering during the initial setup phase, and to define an
interoperable multisig configuration format.

Concerns #4 and #5 should be handled by Signers and are out of scope
of this proposal.

==Specification==

===Prerequisites===
This proposal assumes the parties in the multisig support
[https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki
BIP-0032], [https://github.com/bitcoin/bips/blob/master/bip-0322.mediawiki
BIP-0322], [https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md
the descriptor language] and [https://tools.ietf.org/html/rfc3686 AES
encryption].

===File Extension===
All descriptor and key records should have a <tt>.bsms</tt> file
extension. Encrypted data should have a <tt>.dat</tt> extension.

===Roles===
====Coordinator====

The Coordinator initiates the multisig setup. The Coordinator
determines what type of multisig is used and the exact policy script.
If encryption is enabled, the Coordinator also distributes a shared
secret or shared secrets to the parties involved for secure
communication. The Coordinator gathers information from the Signers to
generate a descriptor record. The Coordinator distributes the
descriptor record back to the Signers.

====Signer====

The Signer is a participating member in the multisig. Its
responsibilities include providing its key record -- which contains an
Extended Public Key (XPUB) -- to the Coordinator, verifying that its
XPUB is included in the descriptor record and persisting the
descriptor record in its storage.

===Setup Process===

====Round 1====

=====Coordinator=====

* The Coordinator creates a new multisig wallet creation session. The
Coordinator constructs the multisig script and its policy parameters,
such as the required number of signatures and the total number of
Signers (<tt>M</tt> and <tt>N</tt>).
* The session should expire after some time period determined by the
Coordinator, e.g., 24 hours. The timeout allows the encryption key to
have lower entropy.
* If encryption is enabled, the Coordinator distributes a secret
<tt>TOKEN</tt> to each Signer over a secure channel. The Signer can
use the <tt>TOKEN</tt> to derive an <tt>ENCRYPTION_KEY</tt>. Refer to
the Encryption section below for details on the <tt>TOKEN</tt>, the
key derivation function and the encryption scheme. Depending on the
use case, the Coordinator can decide whether to share one common
<tt>TOKEN</tt> for all Signers, or to have one per Signer.
* If encryption is disabled, the <tt>TOKEN</tt> is set to <tt>0</tt>,
and all the encryption/decryption steps below can be skipped.

=====Signer=====

* The Signer initiates the multisig wallet creation session by setting
the <tt>TOKEN</tt>. The Signer derives an <tt>ENCRYPTION_KEY</tt> from
the <tt>TOKEN</tt>. The Signer can keep the session open until a
different value for the <tt>TOKEN</tt> is set.
* The Signer generates a key record by prompting the user for a
multisig derivation path and retrieves the XPUB at that derivation
path. Alternatively, the Signer can choose a path on behalf of the
user. If the Signer chooses the path, it should try to avoid reusing
XPUBs for different wallets.
* The first line in the record must be the specification version
(<tt>BSMS 1.0</tt> as of this writing). The second line must be the
hex-encoded <tt>TOKEN</tt>. The third line must be the <tt>KEY</tt>.
The <tt>KEY</tt> is an XPUB plus its key origin information, written
in the descriptor-defined format, i.e.: <tt>[{master key
fingerprint}/{derivation path}]{XPUB}</tt>. The fourth line is a text
description of the key, 80 characters maximum. The fifth line must be
a <tt>SIG</tt>, whereas <tt>SIG</tt> is the signature generated by
using the private key associated with the XPUB to sign the first four
lines. The signature should follow
[https://github.com/bitcoin/bips/blob/master/bip-0322.mediawiki
BIP-0322], legacy format accepted.
* The Signer calculates the Message Authentication Code (<tt>MAC</tt>)
for the record. The first 16 bytes of the <tt>MAC</tt> serves as the
Initialization Vector (<tt>IV</tt>) for the encryption.
* The Signer encrypts the key record with the <tt>ENCRYPTION_KEY</tt>
and <tt>IV</tt>.
* The Signer encodes the <tt>MAC</tt> and the ciphertext into
hexadecimal format, then concatenates the results: <tt>(MAC ||
ciphertext)</tt>.

====Round 2====

=====Coordinator=====

* The Coordinator gathers key records from all participating Signers.
The Coordinator verifies that there are exactly <tt>N</tt> unique key
records before the wallet setup session expires.
* For each key record, the Coordinator extracts the <tt>MAC</tt> from
the data, sets <tt>IV</tt> to the first 16 bytes of the <tt>MAC</tt>,
then decrypts the ciphertext using the <tt>ENCRYPTION_KEY</tt> and
<tt>IV</tt>.
* The Coordinator verifies that the included <tt>MAC</tt> is valid
given the plaintext.
* The Coordinator verifies that the key records have compatible
specification versions.
* The Coordinator verifies that the included <tt>SIG</tt> is valid
given the <tt>KEY</tt>.
* If all key records look good, the Coordinator fills in all necessary
information to generate a descriptor record.
* The first line in the descriptor record must be the specification
version (<tt>BSMS 1.0</tt> as of this writing). The second line must
be a comma-separated list of accepted derivation paths that the
Signers can use to generate addresses from the included XPUBs. The
paths must start with <tt>/</tt> and use non-hardened derivation. For
example, <tt>/0/*</tt> and <tt>/1/*</tt> are some common paths. If
there are no restrictions, it must say <tt>No path restrictions</tt>.
The third line must be the descriptor string plus a <tt>CHECKSUM</tt>,
all in one line. The <tt>CHECKSUM</tt> has
[https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md#checksums
BECH32 encoding].
* The Coordinator calculates the <tt>MAC</tt> for the record. The
first 16 bytes of the <tt>MAC</tt> serves as the <tt>IV</tt> for the
encryption..
* The Coordinator encrypts the descriptor record with the
<tt>ENCRYPTION_KEY</tt> and <tt>IV</tt>.
* The Coordinator encodes the <tt>MAC</tt> and the ciphertext into
hexadecimal format, then concatenates the results: <tt>(MAC ||
ciphertext)</tt>.
* The Coordinator sends the encrypted descriptor record to all
participating Signers.

=====Signer=====

* The Signer imports the descriptor record.
* The Signer extracts the <tt>MAC</tt> from the data, sets <tt>IV</tt>
to the first 16 bytes of the <tt>MAC</tt>, then decrypts the
ciphertext using the <tt>ENCRYPTION_KEY</tt> (derived from the open
session) and <tt>IV</tt>.
* The Signer verifies that the included <tt>MAC</tt> is valid given
the plaintext.
* The Signer verifies that it can support the included specification version.
* The Signer verifies that it is compatible with the derivation path
restrictions.
* The Signer verifies the descriptor’s <tt>CHECKSUM</tt>.
* The Signer verifies that it can support the descriptor.
* The Signer checks that its <tt>KEY</tt> is included in the
descriptor, using path and fingerprint information provided. The check
must perform an exact match on the <tt>KEY</tt>s and not using
shortcuts such as matching fingerprints, which is trivial to spoof.
* For confirmation, the Signer must display to the user the
<tt>CHECKSUM</tt>, the derivation path restrictions and the policy
parameters, such as <tt>M</tt>, <tt>N</tt> and the position(s) of its
own XPUB in the policy script. The total number of Signers,
<tt>N</tt>, is important to prevent a <tt>KEY</tt> insertion attack.
The position is important for scripts where key order matters. When
applicable, all positions of the XPUB must be displayed. The full
descriptor must also be available for review upon user request.
* When possible, the Signer should also show a preview of the first
address(es) of the wallet.
* Parties must check with each other that all Signers have verified
the descriptor and has the same confirmation (except for the key
positions).
* If all checks pass, the Signer must persist the descriptor record in
its storage.

This completes the setup.

===Encryption===

====The Token====
We define three modes of encryption.

# <tt>NO_ENCRYPTION</tt> : the <tt>TOKEN</tt> is set to <tt>0</tt>.
Encryption is disabled.
# <tt>STANDARD</tt> : the <tt>TOKEN</tt> is a 64-bit nonce.
# <tt>EXTENDED</tt> : the <tt>TOKEN</tt> is a 96-bit nonce.

The <tt>TOKEN</tt> can be converted to one of these formats:
* A decimal number (recommended). The number must not exceed the
maximum value of the nonce.
* A mnemonic phrase using
[https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki
BIP-0039] word list (6 words in <tt>STANDARD</tt> mode; 9 words in
<tt>EXTENDED</tt> mode).
* A QR code.
* Other formats.

The flexibility in the data format allows each Signer to customize the
User Experience based on its respective capabilities.

====Key Derivation====
The key derivation function is [https://tools.ietf.org/html/rfc2898
PBKDF2], with PRF = SHA512. Specifically:

<tt>DKey = PBKDF2(PRF, Password, Salt, c, dkLen)</tt>

Whereas:

* PRF = SHA512
* Password = "No SPOF"
* Salt = <tt>TOKEN</tt>
* c = 2048
* dkLen = 256
* DKey = Derived <tt>ENCRYPTION_KEY</tt>

====Encryption Scheme====
The encryption scheme is [https://tools.ietf.org/html/rfc3686 AES-256-CTR].

<tt>MAC = HMAC-SHA256(HMAC_Key, hex-encoded TOKEN || Data)</tt>

<tt>IV = First 16 bytes of MAC</tt>

<tt>Ciphertext = AES-256-CTR-Encrypt(Plaintext, DKey, IV)</tt>

<tt>Plaintext = AES-256-CTR-Decrypt(Ciphertext, DKey, IV)</tt>

Whereas:
* DKey = <tt>ENCRYPTION_KEY</tt>
* HMAC_Key = SHA256(<tt>ENCRYPTION_KEY</tt>)
* Data = the plaintext, e.g. the entire key record in round 1 and the
entire descriptor record in round 2

The <tt>MAC</tt> is to be sent along with the key and descriptor
record, as specified above. Because it is a <tt>MAC</tt> over the
entire plaintext, this is essentially an
[https://en.wikipedia.org/wiki/Authenticated_encryption#Encrypt-and-MAC_(E&M)
Encrypt-and-MAC] form of authenticated encryption.

==QR Codes==
For signers that use QR codes to transmit data, key and descriptor
records can be converted to QR codes, following
[https://github.com/BlockchainCommons/Research/blob/master/papers/bcr-2020-005-ur.md
the BCR standard].

Also refer to [https://github.com/BlockchainCommons/Research/blob/master/papers/bcr-2020-015-account.md
UR Type Definition for BIP44 Accounts] and
[https://github.com/BlockchainCommons/Research/blob/master/papers/bcr-2020-010-output-desc.md
UR Type Definition for Bitcoin Output Descriptors] for more details.

==Security==

This proposal introduces two layers of protection. The first one is a
temporary, secret <tt>TOKEN</tt>. The second one is the descriptor
<tt>CHECKSUM</tt>.

The <tt>TOKEN</tt> is used to encrypt the two rounds of communication
between the Signer and the Coordinator. A <tt>MAC</tt> is also
generated from the <tt>TOKEN</tt> and plaintext to authenticate the
data being exchanged. The <tt>TOKEN</tt> is only needed during the
setup phase, and can be safely discarded afterwards.

The descriptor <tt>CHECKSUM</tt>, on the other hand, can be used to
verify the integrity of the multisig configuration. An attacker who
tampers with the multisig configuration must also change the
descriptor <tt>CHECKSUM</tt>. Parties must check with each other that
all Signers have the same <tt>CHECKSUM</tt>, along with the policy
parameters, to reduce the chance of tampering. The <tt>CHECKSUM</tt>
must be persisted along with the descriptor in each Signer’s storage.

The <tt>TOKEN</tt> and the <tt>CHECKSUM</tt> can’t guarantee complete
protection, since that depends on the overall security of all parties
in the setup, but they can make it significantly harder for an
attacker to tamper with the multisig configuration.

==Privacy==
Encryption helps improve the privacy of the wallet by avoiding sharing
XPUBs and descriptors in plaintext.

If the parties wish to have stronger privacy, it is recommended to use
a higher number of bits for the <tt>TOKEN</tt>, and to completely
erase knowledge of the <tt>TOKEN</tt> after the multisig wallet has
been set up.

==Test Vectors==

===Mode: <tt>NO_ENCRYPTION</tt>===
====ROUND 1====
* Coordinator
** M-of-N: 2/2
** ADDRESS_TYPE: NATIVE_SEGWIT
** TOKEN: 0

* Signer 1
** MASTER_KEY_FINGERPRINT: 539f3d89
** PRIVATE_KEY (m/48'/0'/0'/2'):
KyoXqiwiz6qm21BSYebiZFfNF7obkhiJW6TdPMZTQQMF4kZtfD78
** XPUB (m/48'/0'/0'/2'):
xpub6ETerig7tq89mtaD8Gau2xRWxouRMBy6XHqciA8GZzC2dJv3w6FxfgoegH4b2qYF4oG6VBrhpLrauPs5E1q58GLCnhKp6g9QsV9ZA7J5JNa
** Legacy signature
** <tt>signer_1_key.bsms</tt>:
<pre>BSMS 1.0
00
[539f3d89/48'/0'/0'/2']xpub6ETerig7tq89mtaD8Gau2xRWxouRMBy6XHqciA8GZzC2dJv3w6FxfgoegH4b2qYF4oG6VBrhpLrauPs5E1q58GLCnhKp6g9QsV9ZA7J5JNa
Signer 1 key
IPXsnNSZb8M6H4fAWtpjAc75hyHHd89fskpM5o7qFg+mPDzEPc1k2mjuIpVIIzaCe45FwPfAAa91RaStfC5Sak0=</pre>

* Signer 2
** MASTER_KEY_FINGERPRINT: f8b12aa6
** PRIVATE_KEY (m/48'/0'/0'/2'):
L1zht7muKnUYFMdzC3jwXd78u8tGoKr46AXGh4waF9nphUYWq7ow
** XPUB (m/48'/0'/0'/2'):
xpub6EWPNhGSX86SN4J2DrBUaQ826o6V4egHqAJZUDJqnsthv9CcjBZV79u68M3YZkuTJnJBXfCrHuJy97fkVurntwgt3V7Ms5hXpJV2vS8fQZM
** Legacy signature
** <tt>signer_2_key.bsms</tt>:
<pre>BSMS 1.0
00
[f8b12aa6/48'/0'/0'/2']xpub6EWPNhGSX86SN4J2DrBUaQ826o6V4egHqAJZUDJqnsthv9CcjBZV79u68M3YZkuTJnJBXfCrHuJy97fkVurntwgt3V7Ms5hXpJV2vS8fQZM
Signer 2 key
H38+lp9iaesBeCN05BDTH/SnmarlH6+X+Kmw1pgCk+c1Pc1evYIdBag9Nc0nsKhvPtfEbRt9r/qsUVZ5onCtBTc=</pre>

====ROUND 2====
* Coordinator
** <tt>my_multisig_wallet.bsms</tt>:
<pre>BSMS 1.0
/0/*,/1/*
wsh(sortedmulti(2,[539f3d89/48'/0'/0'/2']xpub6ETerig7tq89mtaD8Gau2xRWxouRMBy6XHqciA8GZzC2dJv3w6FxfgoegH4b2qYF4oG6VBrhpLrauPs5E1q58GLCnhKp6g9QsV9ZA7J5JNa/*,[f8b12aa6/48'/0'/0'/2']xpub6EWPNhGSX86SN4J2DrBUaQ826o6V4egHqAJZUDJqnsthv9CcjBZV79u68M3YZkuTJnJBXfCrHuJy97fkVurntwgt3V7Ms5hXpJV2vS8fQZM/*))#fntxdj7p</pre>

===Mode: <tt>STANDARD</tt> Encryption===
====ROUND 1====
* Coordinator
** M-of-N: 2/2
** ADDRESS_TYPE: NATIVE_SEGWIT
** TOKEN (hex): 1ed4ba49e96336b8
*** TOKEN (decimal): 2221605342811469496
*** TOKEN (mnemonic): burst place mystery spot cricket foster
** ENCRYPTION_KEY (hex):
72185a0e25b4efc5d6ac0f8ed32b0165199100e32385040e3a48eb30164bf492

* Signer 1
** MASTER_KEY_FINGERPRINT: 98d79e95
** PRIVATE_KEY (m/48'/0'/0'/2'):
KydC7hZFtWe56oQUAw14HvQ3gKeKVd3m8frFgVMxUqpuhKHvcmm3
** XPUB (m/48'/0'/0'/2'):
xpub6DvvwHS5pd1D36xt4YBGJvtdThWXfn8L9qRj9DbFMExMeP6eBE6Aw9WyBC7XUQwiPPDFurirewsKZpYv68yTV5RBy7SZmw45QEkaLka5BCt
** Legacy signature
** <tt>signer_1_key.bsms</tt>:
<pre>BSMS 1.0
1ed4ba49e96336b8
[98d79e95/48'/0'/0'/2']xpub6DvvwHS5pd1D36xt4YBGJvtdThWXfn8L9qRj9DbFMExMeP6eBE6Aw9WyBC7XUQwiPPDFurirewsKZpYv68yTV5RBy7SZmw45QEkaLka5BCt
Signer 1 key
HxtPoP0DrQSac/7ypcwC07R2s6jjpXR6Li2Q92zXj/FSIMQcV5yOU0/ONsDgHXamq0gD5DfPbvuVCp9ZJubclV4=</pre>

* Signer 1 encryption
** HMAC_KEY (hex):
4dab3988cbc683ad7a8c93d43f9b11a78b63a93d5e33ea19c603f4b7b87ac284
** MAC (hex): afe99e92f0eadc3308eb990045e90a4f54e9f59d22aae5034ac3d866d29c508d
** IV (hex) : afe99e92f0eadc3308eb990045e90a4f
** CIPHERTEXT (hex):
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
** <tt>signer_1_key.dat</tt>:
<pre>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</pre>

* Signer 2
** MASTER_KEY_FINGERPRINT: 3e94b5a1
** PRIVATE_KEY (m/48'/0'/0'/2'):
KyPh5XYjExjNHPiBjYhp8iAntAehrDziiwRv7y9Ln6eK9QU2xP55
** XPUB (m/48'/0'/0'/2'):
xpub6E1W1DUYY29V2b8czCcpi36GG2uD33B11vwNopgTZwsVyfgAkA4kPCqLP5R4YzaRvzW17CQrDkgmDQbA848AdkR7W18nNvMKXzzCBSnZP9c
** Legacy signature
** <tt>signer_2_key.bsms</tt>:
<pre>BSMS 1.0
1ed4ba49e96336b8
[3e94b5a1/48'/0'/0'/2']xpub6E1W1DUYY29V2b8czCcpi36GG2uD33B11vwNopgTZwsVyfgAkA4kPCqLP5R4YzaRvzW17CQrDkgmDQbA848AdkR7W18nNvMKXzzCBSnZP9c
Signer 2 key
ILR49QLy9+xkMS11TIXJRSMgOQOzGbAaooq4/ZRcd8VgM6j5upJMI0mjJHseQOMYSGk8FqjXZbMvBGyiX9wdutM=</pre>

* Signer 2 encryption
** HMAC_KEY (hex):
4dab3988cbc683ad7a8c93d43f9b11a78b63a93d5e33ea19c603f4b7b87ac284
** MAC (hex): 5c7cb2ac407cd60b1f2b86ef46077d3a312b6ce921df2a141347e8bf1e5c6573
** IV (hex) : 5c7cb2ac407cd60b1f2b86ef46077d3a
** CIPHERTEXT (hex):
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
** <tt>signer_2_key.dat</tt>:
<pre>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</pre>

====ROUND 2====
*Coordinator
** <tt>my_multisig_wallet.bsms</tt>:
<pre>BSMS 1.0
/0/*,/1/*
wsh(sortedmulti(2,[98d79e95/48'/0'/0'/2']xpub6DvvwHS5pd1D36xt4YBGJvtdThWXfn8L9qRj9DbFMExMeP6eBE6Aw9WyBC7XUQwiPPDFurirewsKZpYv68yTV5RBy7SZmw45QEkaLka5BCt/*,[3e94b5a1/48'/0'/0'/2']xpub6E1W1DUYY29V2b8czCcpi36GG2uD33B11vwNopgTZwsVyfgAkA4kPCqLP5R4YzaRvzW17CQrDkgmDQbA848AdkR7W18nNvMKXzzCBSnZP9c/*))#x0lx92qk</pre>

*Coordinator encryption
** HMAC_KEY (hex):
4dab3988cbc683ad7a8c93d43f9b11a78b63a93d5e33ea19c603f4b7b87ac284
** MAC (hex): df3d06db6c8b8a5f25de202e10ea225df6415d1ed0e36c64cc2be1b7e86c2a38
** IV (hex) : df3d06db6c8b8a5f25de202e10ea225d
** CIPHERTEXT (hex):
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
** <tt>my_multisig_wallet.dat</tt>:
<pre>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</pre>

===Mode: <tt>EXTENDED</tt> Encryption===
====ROUND 1====
*Coordinator
** M-of-N: 2/3
** ADDRESS_TYPE: NESTED_SEGWIT
** TOKEN for Signer 1 (hex): 654d63309464afcda558c6aa
*** TOKEN (decimal): 31351541690484562733651510954
*** TOKEN (mnemonic): grab help slow churn enough traffic nice boat price
*** ENCRYPTION_KEY (hex):
4073adac2351e164b8d68039abd9d4b8e4d07adccfdf73ece6e236d60b107802
** TOKEN for Signer 2 (hex): b0344f51d5cb04083d598fa3
*** TOKEN (decimal): 54532600447720520868878192547
*** TOKEN (mnemonic): rabbit pen stamp process raccoon advice voice
cradle person
*** ENCRYPTION_KEY (hex):
6bae6b670e257d7468c3e90194029dd468a2f39d8b9a3ff187b08209b1d409b6
** TOKEN for Signer 3 (hex): 163fd307195982c4c39d50bb
*** TOKEN (decimal): 6885829092987042066541138107
*** TOKEN (mnemonic): bike write scrub crawl oblige give attack present rookie
*** ENCRYPTION_KEY (hex):
c78b94589214b6dc98b337ba4ce54380553ed00a1e5b1955fc540ce3b30d6566

* Signer 1
** MASTER_KEY_FINGERPRINT: 110dc257
** PRIVATE_KEY (m/48'/0'/0'/1'):
KzshDDEBhzyiwXHoyE7ZiLegzztEy54AG6Wq8N844LqHSQMHt4Ji
** XPUB (m/48'/0'/0'/1'):
xpub6EPQbDFezXYvVFHqnc8R7QUSE8hTepbyCXU7jJBT4dVm2rQHe1i6isqoj59qhyBiCdKquo6QsgMZNHvEz3BM4cNSszF25siTqLUCznBm8vk
** Legacy signature
** <tt>signer_1_key.bsms</tt>:
<pre>BSMS 1.0
654d63309464afcda558c6aa
[110dc257/48'/0'/0'/1']xpub6EPQbDFezXYvVFHqnc8R7QUSE8hTepbyCXU7jJBT4dVm2rQHe1i6isqoj59qhyBiCdKquo6QsgMZNHvEz3BM4cNSszF25siTqLUCznBm8vk
Signer 1 key
IDX6xLdM4XjetYPvVfpVBXAfT7oE3tHAOB4blZpbIst8bjJ+LbDeP4tZl4O8utAuys9igXE0G3kaHz1mg/+OU8w=</pre>

* Signer 1 encryption
** HMAC_KEY (hex):
f43c359a4b3d7b2e01be73c54519b12545ca9a23a86f824aadf577b314a7caa7
** MAC (hex): 40b6b43e2f1bc01b748eb242235d7e09fa8a2fd6cebe35784cf3adf81910ec98
** IV (hex) : 40b6b43e2f1bc01b748eb242235d7e09
** CIPHERTEXT (hex):
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
** <tt>signer_1_key.dat</tt>:
<pre>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</pre>

* Signer 2
** MASTER_KEY_FINGERPRINT: 5c890401
** PRIVATE_KEY (m/48'/0'/0'/1'):
L41Jnc9CdBtBJd18429MDGcTgP2DNoXaKyyGr271ndTprvrHXDQf
** XPUB (m/48'/0'/0'/1'):
xpub6EW1SmjSXq9YwVwcan5qWEncgx89SozMvGNpYF6hfZHYNTikNZ4gsXuVhHTi6xYJCkmY4X4wpPPS5Gr7aY39dVJMS2TGfihr25oaspKtU8q
** Legacy signature
** <tt>signer_2_key.bsms</tt>:
<pre>BSMS 1.0
b0344f51d5cb04083d598fa3
[5c890401/48'/0'/0'/1']xpub6EW1SmjSXq9YwVwcan5qWEncgx89SozMvGNpYF6hfZHYNTikNZ4gsXuVhHTi6xYJCkmY4X4wpPPS5Gr7aY39dVJMS2TGfihr25oaspKtU8q
Signer 2 key
H5kN6UHaK2xACB6iYdTxxQPD8qyFEYv9iMsQs5B0MRfCM7NA5GB+7EFgmBpSctwt6B122zWBr6mRjpYjKmj+7hs=</pre>

* Signer 2 encryption
** HMAC_KEY (hex):
e0a20b5f5285fbaa35aad08fb70f5626c9abbe1b384a4950735b28aca6325ff2
** MAC (hex): 3a6deec8dbdbd6606a52c7d7e64eca4f972a293cbabac6f62736629fbe77928a
** IV (hex) : 3a6deec8dbdbd6606a52c7d7e64eca4f
** CIPHERTEXT (hex):
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
** <tt>signer_2_key.dat</tt>:
<pre>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</pre>

* Signer 3
** MASTER_KEY_FINGERPRINT: 614cbf5f
** PRIVATE_KEY (m/48'/0'/0'/1'):
L2ccRLzH7GfVxWpU8YSY9y5UGyRoqW3UdeNT1vGfVbxAGhwU5qhD
** XPUB (m/48'/0'/0'/1'):
xpub6F9TfWTFcMYy5Ycd2ka2az1brJj78J2isLAWptZnCpFsesss5sZv5B8xsgt71ZXfhDWhUtf4vng4zY6HUVrQbDMPDYRLYvFFoLnAYfzgYPH
** Legacy signature
** <tt>signer_3_key.bsms</tt>:
<pre>BSMS 1.0
163fd307195982c4c39d50bb
[614cbf5f/48'/0'/0'/1']xpub6F9TfWTFcMYy5Ycd2ka2az1brJj78J2isLAWptZnCpFsesss5sZv5B8xsgt71ZXfhDWhUtf4vng4zY6HUVrQbDMPDYRLYvFFoLnAYfzgYPH
Signer 3 key
H0jf2JMtke5zDDIWys6fihOCA6QBmC5+hbgVB/c2mMPNPLB6tDXt0TFZU1f9wvaCR9762anKSc8CCqXLogw8V00=</pre>

* Signer 3 encryption
** HMAC_KEY (hex):
1f51ea067c121e2f86af5e1d484905046bc63e861573157d8b1ae9e7e47e224b
** MAC (hex): 1a5624fcb39cebabb6174456173eec19b756bc916cf2c9d815e9bcce070898c4
** IV (hex) : 1a5624fcb39cebabb6174456173eec19
** CIPHERTEXT (hex):
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
** <tt>signer_3_key.dat</tt>:
<pre>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</pre>

====ROUND 2====
* Coordinator
** <tt>my_multisig_wallet.bsms</tt>:
<pre>BSMS 1.0
/0/*,/1/*
sh(wsh(multi(2,[110dc257/48'/0'/0'/1']xpub6EPQbDFezXYvVFHqnc8R7QUSE8hTepbyCXU7jJBT4dVm2rQHe1i6isqoj59qhyBiCdKquo6QsgMZNHvEz3BM4cNSszF25siTqLUCznBm8vk/*,[5c890401/48'/0'/0'/1']xpub6EW1SmjSXq9YwVwcan5qWEncgx89SozMvGNpYF6hfZHYNTikNZ4gsXuVhHTi6xYJCkmY4X4wpPPS5Gr7aY39dVJMS2TGfihr25oaspKtU8q/*,[614cbf5f/48'/0'/0'/1']xpub6F9TfWTFcMYy5Ycd2ka2az1brJj78J2isLAWptZnCpFsesss5sZv5B8xsgt71ZXfhDWhUtf4vng4zY6HUVrQbDMPDYRLYvFFoLnAYfzgYPH/*)))#j3ykhz7f</pre>

* Send to Signer 1:
** HMAC_KEY (hex):
f43c359a4b3d7b2e01be73c54519b12545ca9a23a86f824aadf577b314a7caa7
** MAC (hex): ee74a0f50943d7d1b65270028bb05133e87c832cdc1ef0a07c79db2093ca3432
** IV (hex) : ee74a0f50943d7d1b65270028bb05133
** CIPHERTEXT (hex):
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
** <tt>my_multisig_wallet_for_signer_1.dat</tt>:
<pre>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</pre>

* Send to Signer 2:
** HMAC_KEY (hex):
e0a20b5f5285fbaa35aad08fb70f5626c9abbe1b384a4950735b28aca6325ff2
** MAC (hex): 81df9e064f1de1d5f754c4e20f9286f9d81b856d3965677a9f2430cb9297ad1f
** IV (hex) : 81df9e064f1de1d5f754c4e20f9286f9
** CIPHERTEXT (hex):
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
** <tt>my_multisig_wallet_for_signer_2.dat</tt>:
<pre>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</pre>

* Send to Signer 3:
** HMAC_KEY (hex):
1f51ea067c121e2f86af5e1d484905046bc63e861573157d8b1ae9e7e47e224b
** MAC (hex): 159a91100cacd123480b7d085c8bb32ec8eb06f0391b6dc8fac07ae67eb37b81
** IV (hex) : 159a91100cacd123480b7d085c8bb32e
** CIPHERTEXT (hex):
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
** <tt>my_multisig_wallet_for_signer_3.dat</tt>:
<pre>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</pre>

==Acknowledgement==

Special thanks to Pavol Rusnak, Dmitry Petukhov, Christopher Allen,
Craig Raw, Robert Spigler, Gregory Sanders, Ta Tat Tai, Michael
Flaxman, Pieter Wuille and others for their feedback on the
specification.

==References==

Original mailing list thread:
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2021-February/018385.html