In this commit, we extend the initial wallet creation set up case with
the goal of giving the user the ability to restore a prior wallet from
seed, or obtain the mnemonic for a newly generated wallet.
As the WalletUnlocker has been extended to allow passing a user source
of entropy, if this is detected, then we’ll use BIP39 to covert it into
an HD wallet seed. Otherwise, we’ll generate our own entropy, then
convert that into the wallet seed.
In order to make this change, we’ll now manually create the default
wallet ourselves. In the case that the user didn’t provide their own
seed, we’ll send the seed we generated back to the user. This will allow
frontends to display the newly generated seed to the end user.
In this commit, we extend the UnlockerService to account for the new
changes in the lnrpc definition. Setting up the daemon for the first
time is now two step process: first the user will generate a new seed
via the GenSeed method, then the user will present this new seed (and
optional pass) to the InitWallet method which then will finalize the
wallet creation.
This two step process ensures that we don't commit the wallet changes
in the case that the user doesn't actually "ACK" the new seed.
In the case that the user already has an existing seed, they can
re-enter it and skip straight to the InitWallet step.
We also update the tests to account for the new API changes.
In this commit, we revamp the WalletUnlocker service to now have a
two-stage init process.
The first (optional) is for the user instantiating a new lnd instance to
call the GenSeed method with an optional aezeed passphrase. The response
to this will be a freshly generated aezeed mnemonic along with the
original enciphered seed.
The second step will be the actual wallet initaliztion. By separating
this step from seed generation, UI's will be able to ensure that the
user has written down the seed, before proceeding and committing the
seed to the internal wallet. The new method InitWallet accepts a wallet
passphrase, the aezeed mnemonic, and the optional passphrase.
This commit resolves an issue where glide would try to install an older
version of x/crypto, which for me resulted in blake2b not exposing the
interfaces required by the new aezeed package. Using the explicit
version has seemed to resolve this entirely.
In this commit we add a set of benchmarks to be able to measure the
enciphering and deciphering speed of the current scheme with the
current scrypt parameters.
On my laptop I get about 100ms per attempt:
⛰ go test -run=XXX -bench=.
goos: darwin
goarch: amd64
pkg: github.com/lightningnetwork/lnd/aezeed
BenchmarkToMnenonic-4 10 102287840 ns/op
BenchmarkFromMnenonic-4 10 105874973 ns/op
PASS
ok github.com/lightningnetwork/lnd/aezeed 3.036s
In this commit, we add a new package implementing the aezeed cipher
seed scheme. This is a new scheme developed that aims to overcome the
two major short comings of BIP39: a lack of a version, and a lack of a
wallet birthday. A lack a version means that wallets may not
necessarily know *how* to re-derive addresses during the recovery
process. A lack of a birthday means that wallets don’t know how far
back to look in the chain to ensure that they derive *all* the proper
user addresses.
The aezeed scheme addresses these two drawbacks and adds a number of
desirable features. First, we start with the following plaintext seed:
{1 byte internal version || 2 byte timestamp || 16 bytes of entropy}.
The version field is for wallets to be able to know *how* to re-derive
the keys of the wallet.
The 2 byte timestamp is expressed in Bitcoin Days Genesis, meaning that
the number of days since the timestamp in Bitcoin’s genesis block. This
allow us to save space, and also avoid using a wasteful level of
granularity. With the currently, this can express time up until 2188.
Finally, the entropy is raw entropy that should be used to derive
wallet’s HD root.
Next, we’ll take the plaintext seed described above and encipher it to
procure a final cipher text. We’ll then take this cipher text (the
CipherSeed) and encode that using a 24-word mnemonic. The enciphering
process takes a user defined passphrase. If no passphrase is provided,
then the string “aezeed” will be used.
To encipher a plaintext seed (19 bytes) to arrive at an enciphered
cipher seed (33 bytes), we apply the following operations:
* First we take the external version an append it to our buffer. The
external version describes *how* we encipher. For the first version
(version 0), we’ll use scrypt(n=32768, r=8, p=1) and aezeed.
* Next, we’ll use scrypt (with the version 9 params) to generate a
strong key for encryption. We’ll generate a 32-byte key using 5 bytes
as a salt. The usage of the salt is meant to make the creation of
rainbow tables infeasible.
* Next, the enciphering process. We use aezeed, modern AEAD with
nonce-misuse resistance properties. The important trait we exploit is
that it’s an *arbitrary input length block cipher*. Additionally, it
has what’s essentially a configurable MAC size. In our scheme we’ll use
a value of 4, which acts as a 32-bit checksum. We’ll encrypt with our
generated seed, and use an AD of (version || salt). We'll them compute a
checksum over all the data, using crc-32, appending the result to the
end.
* Finally, we’ll encode this 33-byte cipher text using the default
world list of BIP 39 to produce 24 english words.
The `aezeed` cipher seed scheme has a few cool properties, notably:
* The mnemonic itself is a cipher text, meaning leaving it in
plaintext is advisable if the user also set a passphrase. This is in
contrast to BIP 39 where the mnemonic alone (without a passphrase) may
be sufficient to steal funds.
* A cipherseed can be modified to *change* the passphrase. This
means that if the users wants a stronger passphrase, they can decipher
(with the old passphrase), then encipher (with a new passphrase).
Compared to BIP 39, where if the users used a passphrase, since the
mapping is one way, they can’t change the passphrase of their existing
HD key chain.
* A cipher seed can be *upgraded*. Since we have an external version,
offline tools can be provided to decipher using the old params, and
encipher using the new params. In the future if we change ciphers,
change scrypt, or just the parameters of scrypt, then users can easily
upgrade their seed with an offline tool.
* We're able to verify that a user has input the incorrect passphrase,
and that the user has input the incorrect mnemonic independently.
In router_test FindRoutes is passing DefaultFinalCLTVDelta in place
where numPaths is expected. This commit passes a default numPaths for
function calls to FindRoutes so that final cltv delta are correctly
passed.
initiated by the user doesn't timeout.
Split assertNumPendingChannels into assertNumPendingChannelsRemains,
and assertNumPendingChannelsRemains to prevent possible false
positives passing tests
In this commit, we fix a bug in the query routes RPC that could at
times lead to a panic. This would happen if the number of returned
routes was less than the number of expected routes. To remedy this,
we’ll return the minimum of the number of requested routes, and the
number of routes actually returned.
In this commit, we reduce the total number of allocations that a
brontide session will incur over its lifetime. Profiling on one of my
nodes showed that we were generating a lot of garbage due to
re-creating a 65KB buffer to read the next message each time the
ReadMessage method was called.
To reduce the total number of memory allocations, we’ll now simply
re-use a buffer for both the cipher text header, and the cipher text
itself.
