struct CircomVk in circomVerifier.go doesn't fit the structure in verification_key.json

[KimiWu123]

The definition of CircomVk is as follows,

type CircomVk struct {
    IC          [][3]string     `json:"IC"`
    Alpha1      [3]string       `json:"vk_alfa_1"`
    Beta2       [3][2]string    `json:"vk_beta_2"`
    Gamma2      [3][2]string    `json:"vk_gamma_2"`
    Delta2      [3][2]string    `json:"vk_delta_2"`
    AlphaBeta12 [2][3][2]string `json:"vk_alpfabeta_12"` // not really used, for the moment in go-snarks calculed in verification time
}

but the content in verification_key.json is,

{
 "protocol": "original",
 "nPublic": 5,
 "IC": [
  [
   "5909516017194887780014591301321780000892722821844951797826181001577727880581",
   "5329499221348621305139189103574471329196927280375866642048788071019202104643",
   "1"
  ],
  [
   "935644606830232956841380613504100798489330973974012775460541844770939873930",
   "10575569456856898614999681968827310750912991389249253122340224794782861723306",
   "1"
  ],
  [
   "13649240896101396584274089976767050482745318382794080050529031145918840993339",
   "15326197904619302955821217670131741587544043105130204038949145581175664774587",
   "1"
  ],
  [
   "9307940889852353280370252557168219050564177799946769537078370018295314042246",
   "5855041362972278333848450371323927750278033867635108806943844781656235322005",
   "1"
  ],
  [
   "124982495315272918975451639013355786819241664185663846673589371451292606806",
   "20681262391016500144106112622654996143553609447716826883723716804683913156762",
   "1"
  ],
  [
   "9864011402884151542868513711373687290716966969300765702995194761202006743987",
   "6570131304974335106240634366550076078020134555110080349895508895480079737884",
   "1"
  ]
 ],
 "vk_a": [
  [
   "16993970916517232918787072215560485171148895275275734264097913550596814341523",
   "14561655239558070696480617258518594818454317115154134354088942688151471434654"
  ],
  [
   "17539591511011966162678931282146724677151415891116365816155342439345331687588",
   "4894111281039109720167768199437379142242290591729170558389185095458550327253"
  ],
  [
   "1",
   "0"
  ]
 ],
 "vk_b": [
  "9370833417351582169071303381856019999732832895900772235487239911169805726294",
  "11825811660232166510973473267110121632073332173785268120046804594368464149848",
  "1"
 ],
 "vk_c": [
  [
   "5379976852419769240736652791775030796033652620609520197291715373396016788922",
   "13729786854636580766228970639243402553525736309567185663753194601443481073772"
  ],
  [
   "10556831635373590762584906017080136976623321830194525401412087699360460303347",
   "11071789529181717078902456508314481501397932640291145963269255686206235573991"
  ],
  [
   "1",
   "0"
  ]
 ],
 "vk_gb_1": [
  "13020676706334169694485790343717839573839762675949469564068359840111730423742",
  "14317282793588605212155357098733107424747707808920240057389330902625447065156",
  "1"
 ],
 "vk_gb_2": [
  [
   "6752320666226692785826718805926677936539169183442263359417457502694903063326",
   "4287864260216772869277339286129712828493361687597296567489868056737323947"
  ],
  [
   "4791863505028738810201868295092709911003827064603964120584617439254836365094",
   "15658239203464300777657848211757887883598907594419396655745053803883769664196"
  ],
  [
   "1",
   "0"
  ]
 ],
 "vk_g": [
  [
   "18264145063074449371260724550620681127732058020021986501624733718877315236801",
   "9112048515992597139276899092390461440362631965736822793567780355405831076791"
  ],
  [
   "864402203442173923232200041404356636453440030314434788833394160726283834420",
   "20692151516158122490482219340955063676904321087360402760904700903083112170729"
  ],
  [
   "1",
   "0"
  ]
 ],
 "vk_z": [
  [
   "18696209424797839679855119840690703163330172566389237106319271207584153306025",
   "9885721613966818283362183702824462488910528846717274065582590501934396091068"
  ],
  [
   "10999808962804051304605007933890825959091465559231021191472460451502797254944",
   "14971870832791303746445447351777371361664839722904519744951866320550252610584"
  ],
  [
   "1",
   "0"
  ]
 ]
}

How can I map these two? I'm willing to modify it but I need helps. Thanks.

[arnaucube]

Yes, the output from circom is transformed into that go struct in this line https://github.com/arnaucube/go-snark/blob/master/externalVerif/circomVerifier.go#L26 that then uses the parsers from utils module from go-snark https://github.com/arnaucube/go-snark/blob/master/utils/base10parsers.go#L456

Also, the example of verification_key.json that in the first message of this issue is with the original protocol, but the actual functionality is for the groth protocol

[KimiWu123]

Sorry, I don't understand. I know the parser coming from. In the CircomVk struct, the json values are vk_alfa_1, va_beta_2... etc, but verification_key.json is using vk_a, vk_b...etc.

"but the actual functionality is for the groth protocol". Do you mean I should use groth protocol in circom when I generate circuit, setup, calculate witness?

[arnaucube]

'original' refears to the https://eprint.iacr.org/2013/279.pdf (Pinocchio), while the 'groth' refears to https://eprint.iacr.org/2016/260.pdf Each one have different structure of Verification Key. The externalVerificator of go-snark to verify snarkjs proofs, is for 'groth', as is the protocol usually used (as the 'original' needs more pairings computation into the verification, so is less optimal)