Commit Graph

34 Commits

Author SHA1 Message Date
moneromooo-monero
1e5491e942
Add a chacha20 variant to go with chacha8 2017-12-25 19:28:03 +00:00
moneromooo-monero
4c313324b1
Add N/N multisig tx generation and signing
Scheme by luigi1111:

    Multisig for RingCT on Monero

    2 of 2

    User A (coordinator):
    Spendkey b,B
    Viewkey a,A (shared)

    User B:
    Spendkey c,C
    Viewkey a,A (shared)

    Public Address: C+B, A

    Both have their own watch only wallet via C+B, a

    A will coordinate spending process (though B could easily as well, coordinator is more needed for more participants)

    A and B watch for incoming outputs

    B creates "half" key images for discovered output D:
    I2_D = (Hs(aR)+c) * Hp(D)

    B also creates 1.5 random keypairs (one scalar and 2 pubkeys; one on base G and one on base Hp(D)) for each output, storing the scalar(k) (linked to D),
    and sending the pubkeys with I2_D.

    A also creates "half" key images:
    I1_D = (Hs(aR)+b) * Hp(D)

    Then I_D = I1_D + I2_D

    Having I_D allows A to check spent status of course, but more importantly allows A to actually build a transaction prefix (and thus transaction).

    A builds the transaction until most of the way through MLSAG_Gen, adding the 2 pubkeys (per input) provided with I2_D
    to his own generated ones where they are needed (secret row L, R).

    At this point, A has a mostly completed transaction (but with an invalid/incomplete signature). A sends over the tx and includes r,
    which allows B (with the recipient's address) to verify the destination and amount (by reconstructing the stealth address and decoding ecdhInfo).

    B then finishes the signature by computing ss[secret_index][0] = ss[secret_index][0] + k - cc[secret_index]*c (secret indices need to be passed as well).

    B can then broadcast the tx, or send it back to A for broadcasting. Once B has completed the signing (and verified the tx to be valid), he can add the full I_D
    to his cache, allowing him to verify spent status as well.

    NOTE:
    A and B *must* present key A and B to each other with a valid signature proving they know a and b respectively.
    Otherwise, trickery like the following becomes possible:
    A creates viewkey a,A, spendkey b,B, and sends a,A,B to B.
    B creates a fake key C = zG - B. B sends C back to A.
    The combined spendkey C+B then equals zG, allowing B to spend funds at any time!
    The signature fixes this, because B does not know a c corresponding to C (and thus can't produce a signature).

    2 of 3

    User A (coordinator)
    Shared viewkey a,A
    "spendkey" j,J

    User B
    "spendkey" k,K

    User C
    "spendkey" m,M

    A collects K and M from B and C
    B collects J and M from A and C
    C collects J and K from A and B

    A computes N = nG, n = Hs(jK)
    A computes O = oG, o = Hs(jM)

    B anc C compute P = pG, p = Hs(kM) || Hs(mK)
    B and C can also compute N and O respectively if they wish to be able to coordinate

    Address: N+O+P, A

    The rest follows as above. The coordinator possesses 2 of 3 needed keys; he can get the other
    needed part of the signature/key images from either of the other two.

    Alternatively, if secure communication exists between parties:
    A gives j to B
    B gives k to C
    C gives m to A

    Address: J+K+M, A

    3 of 3

    Identical to 2 of 2, except the coordinator must collect the key images from both of the others.
    The transaction must also be passed an additional hop: A -> B -> C (or A -> C -> B), who can then broadcast it
    or send it back to A.

    N-1 of N

    Generally the same as 2 of 3, except participants need to be arranged in a ring to pass their keys around
    (using either the secure or insecure method).
    For example (ignoring viewkey so letters line up):
    [4 of 5]
    User: spendkey
    A: a
    B: b
    C: c
    D: d
    E: e

    a -> B, b -> C, c -> D, d -> E, e -> A

    Order of signing does not matter, it just must reach n-1 users. A "remaining keys" list must be passed around with
    the transaction so the signers know if they should use 1 or both keys.
    Collecting key image parts becomes a little messy, but basically every wallet sends over both of their parts with a tag for each.
    Thia way the coordinating wallet can keep track of which images have been added and which wallet they come from. Reasoning:
    1. The key images must be added only once (coordinator will get key images for key a from both A and B, he must add only one to get the proper key actual key image)
    2. The coordinator must keep track of which helper pubkeys came from which wallet (discussed in 2 of 2 section). The coordinator
    must choose only one set to use, then include his choice in the "remaining keys" list so the other wallets know which of their keys to use.

    You can generalize it further to N-2 of N or even M of N, but I'm not sure there's legitimate demand to justify the complexity. It might
    also be straightforward enough to support with minimal changes from N-1 format.
    You basically just give each user additional keys for each additional "-1" you desire. N-2 would be 3 keys per user, N-3 4 keys, etc.

The process is somewhat cumbersome:

To create a N/N multisig wallet:

 - each participant creates a normal wallet
 - each participant runs "prepare_multisig", and sends the resulting string to every other participant
 - each participant runs "make_multisig N A B C D...", with N being the threshold and A B C D... being the strings received from other participants (the threshold must currently equal N)

As txes are received, participants' wallets will need to synchronize so that those new outputs may be spent:

 - each participant runs "export_multisig FILENAME", and sends the FILENAME file to every other participant
 - each participant runs "import_multisig A B C D...", with A B C D... being the filenames received from other participants

Then, a transaction may be initiated:

 - one of the participants runs "transfer ADDRESS AMOUNT"
 - this partly signed transaction will be written to the "multisig_monero_tx" file
 - the initiator sends this file to another participant
 - that other participant runs "sign_multisig multisig_monero_tx"
 - the resulting transaction is written to the "multisig_monero_tx" file again
 - if the threshold was not reached, the file must be sent to another participant, until enough have signed
 - the last participant to sign runs "submit_multisig multisig_monero_tx" to relay the transaction to the Monero network
2017-12-17 16:11:57 +00:00
moneromooo-monero
383ff4f689
remove "using namespace std" from headers
It's nasty, and actually breaks on Solaris, where if.h fails to
build due to:

  struct map *if_memmap;
2017-11-14 16:56:10 +00:00
Riccardo Spagni
b4126266d4
Merge pull request #2610
44c1d160 unit_tests: fix compiling on Windows (iDunk5400)
2017-10-15 18:54:32 +02:00
iDunk5400
44c1d160c8
unit_tests: fix compiling on Windows 2017-10-08 23:59:08 +02:00
kenshi84
53ad5a0f42
Subaddresses 2017-10-07 13:06:21 +09:00
redfish
540d6fa3d5 tests: pass data dir as arg
This fixes test failure on builds that happen
to be built in 'build/' instead of 'build/release'.

Use boost filesystem path type.
2017-09-28 01:41:44 -04:00
Lee Clagett
4a8f96f95d Improvements for epee binary to hex functions:
- Performance improvements
  - Added `span` for zero-copy pointer+length arguments
  - Added `std::ostream` overload for direct writing to output buffers
  - Removal of unused `string_tools::buff_to_hex`
2017-04-11 16:35:00 -04:00
moneromooo-monero
f065234b71
core: cache tx and block hashes in the respective classes
An idea from smooth
2017-03-23 09:25:17 +00:00
Riccardo Spagni
c3599fa7b9
update copyright year, fix occasional lack of newline at line end 2017-02-21 19:38:18 +02:00
kenshi84
8027ce0c75 extract some basic code from libcryptonote_core into libcryptonote_basic 2017-02-08 22:45:15 +09:00
moneromooo-monero
b3ca0c627a
unit_tests: fix portable serialization tests hardcoded data path 2017-01-14 21:19:33 +00:00
kenshi84
ada7c7da8f portable serializer: tests added 2017-01-03 09:14:48 +09:00
Lee Clagett
d55e2266ca Fixed uninitialized valgrind errors in serialization tests 2016-12-20 12:51:27 -05:00
Shen Noether
76958fc75a
ringct: switch to Borromean signatures 2016-12-04 21:54:11 +00:00
moneromooo-monero
73e8a76d86
tests: fix uninitialized data valgrind reports in serialization tests 2016-11-20 17:25:21 +00:00
moneromooo-monero
ffd8c41f36
ringct: check the size of amount_keys is the same as destinations 2016-10-29 13:33:48 +01:00
moneromooo-monero
7d413f635f
rct: rework serialization to avoid storing vector sizes 2016-09-14 20:23:06 +01:00
moneromooo-monero
93f5c625f0
rct: rework v2 txes into prunable and non prunable data
Nothing is pruned, but this allows easier changes later.
2016-08-28 21:30:18 +01:00
moneromooo-monero
3ab2ab3e76
rct: change the simple flag to a type
for future expansion
2016-08-28 21:30:14 +01:00
Shen Noether
c5be4b0bea
rct: avoid the need for the last II element
This element is used in the generation of the MLSAG, but isn't
needed in verification.
Also misc changes in the cryptonote code to match, by mooo.
2016-08-28 21:30:12 +01:00
moneromooo-monero
b337aea6cc
rct: do not serialize senderPk - it is not used anymore 2016-08-28 21:30:01 +01:00
moneromooo-monero
9b70856ccb
rct: make the amount key derivable by a third party with the tx key
Scheme design from luigi1114.
2016-08-28 21:29:46 +01:00
moneromooo-monero
cf33e1a52a
rct: do not serialize public keys in outPk
They can be reconstructed from vout
2016-08-28 21:29:43 +01:00
moneromooo-monero
a4d4d6194b
integrate simple rct api 2016-08-28 21:29:20 +01:00
moneromooo-monero
6d0e47148b
rct: add the tx prefix hash into the MLSAG
to protect the non-signatures parts of the tx from tampering.
2016-08-28 21:28:58 +01:00
moneromooo-monero
20e50ec7f7
ringct: do not serialize what can be reconstructed
The mixRing (output keys and commitments) and II fields (key images)
can be reconstructed from vin data.
This saves some modest amount of space in the tx.
2016-08-28 21:28:55 +01:00
moneromooo-monero
cc7f449d57
make rct tx serialization work
It may be suboptimal, but it's a pain to have to rebuild everything
when some of this changes.
Also, no clue why there seems to be two different code paths for
serializing a tx...
2016-08-28 21:28:31 +01:00
Riccardo Spagni
de03926850
updated copyright year 2015-12-31 08:39:56 +02:00
Riccardo Spagni
f4b69d553a
year updated in license 2015-01-02 18:52:46 +02:00
Riccardo Spagni
59a8366bb1 Revert "low risk, potentially varint overflow bug patched thanks to BBR"
This reverts commit 4e2b2b942d.
2014-09-25 08:24:42 +02:00
Riccardo Spagni
4e2b2b942d low risk, potentially varint overflow bug patched thanks to BBR 2014-09-24 22:17:33 -04:00
fluffypony
6fc995fe5d License updated to BSD 3-clause 2014-07-23 15:03:52 +02:00
Antonio Juarez
296ae46ed8 moved all stuff to github 2014-03-03 22:07:58 +00:00