getrawtransaction for outputs with multiple addresses #5805

I noted that starting with v0.10.1 the behavior of getrawtransaction when there are multiple addresses in one output has changed.

For example:

getrawtransaction 7657d78f1b69c875d475fe6521db5be03162a861893c462b1a335ebbb10db530 1

used to return 2 addresses for the 2nd output

{
"value" : 0.00007800,
"n" : 1,
"scriptPubKey" : {
"asm" : "1 040286a47e8b11624c510881521b73a02929b9615d219100300c651771c0cf46c04b14cfa790e3f66940d11b5ab3d8ae81a3577473fbd36e2fc2b3d69e91d9af62 1c434e54525052545900000000000000000004ebdf00000015d7a1850000000000 2 OP_CHECKMULTISIG",
"hex" : "5141040286a47e8b11624c510881521b73a02929b9615d219100300c651771c0cf46c04b14cfa790e3f66940d11b5ab3d8ae81a3577473fbd36e2fc2b3d69e91d9af62211c434e54525052545900000000000000000004ebdf00000015d7a185000000000052ae",
"reqSigs" : 1,
"type" : "multisig",
"addresses" : [
"1Po1oXMCWobE6kxWr8rJEP1SRq71JSD3t4",
"1HT7xU2Ngenf7D4yocz2SAcnNLW7rK8d4E"
]
}
}

but now it returns only one address:

{
"value" : 0.00007800,
"n" : 1,
"scriptPubKey" : {
"asm" : "1 040286a47e8b11624c510881521b73a02929b9615d219100300c651771c0cf46c04b14cfa790e3f66940d11b5ab3d8ae81a3577473fbd36e2fc2b3d69e91d9af62 1c434e54525052545900000000000000000004ebdf00000015d7a1850000000000 2 OP_CHECKMULTISIG",
"hex" : "5141040286a47e8b11624c510881521b73a02929b9615d219100300c651771c0cf46c04b14cfa790e3f66940d11b5ab3d8ae81a3577473fbd36e2fc2b3d69e91d9af62211c434e54525052545900000000000000000004ebdf00000015d7a185000000000052ae",
"reqSigs" : 1,
"type" : "multisig",
"addresses" : [
"1Po1oXMCWobE6kxWr8rJEP1SRq71JSD3t4"
]
}
}

@gbeced: the payload:

1c434e54525052545900000000000000000004ebdf00000015d7a1850000000000

... is not a valid public key. 0.9 still converted it into an address, but 0.10 does not.

Would you know if this is related to the changes in CPubKey::IsFullyValid to use secp256k1_ecdsa_verify ? Thanks

I meant secp256k1_ecdsa_pubkey_verify.

@gbeced: this one is to "blame":

Don't return an address for invalid pubkeys: https://github.com/bitcoin/bitcoin/commit/9d7cd4c598edfff12f1f80629c9149b3f1cf75a6 And this is related to this topic: #5247

Edit: a "valid" public key has a size of 33 or 65 byte with correct prefix. To be "fully valid", the public key must represent a valid ECDSA point. This is not new, but was not checked earlier.

Fully valid public keys with embedded data could be created by [prefix|1 byte][payload|31 byte][ecdsa point modificator|1 byte] (or less) where the last byte is modified, until it forms a valid coordinate.

See @petertodd's blockpop library: https://github.com/petertodd/blockpop/blob/master/blockpop/encode.py#L75-L101 or https://github.com/mastercoin-MSC/spec#class-b-transactions-also-known-as-the-multisig-method

Anyway, OP_RETURN should be preferred, but just in case: http://redeem.bitwatch.co/

As this is a feature, not a bug, can you please close the issue? Thank you.