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use both zeropadding and pkcs7 decryption
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himanshu committed Sep 1, 2023
1 parent daa1b91 commit d05ee80
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Showing 2 changed files with 57 additions and 32 deletions.
86 changes: 55 additions & 31 deletions Sources/TorusUtils/Extensions/TorusUtils+extension.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -230,6 +230,40 @@ extension TorusUtils {



private func reconstructKey(decryptedShares: [Int: String], thresholdPublicKey: KeyAssignment.PublicKey) throws -> String? {

// run lagrange interpolation on all subsets, faster in the optimistic scenario than berlekamp-welch due to early exit
let allCombis = kCombinations(s: decryptedShares.count, k: 3)
var returnedKey: String? = nil

for j in 0..<allCombis.count {
let currentCombi = allCombis[j]
let currentCombiShares = decryptedShares.enumerated().reduce(into: [ Int : String ]()) { acc, current in
let (index, curr) = current
if (currentCombi.contains(index)) {
acc[curr.key] = curr.value
}
}
let derivedPrivateKey = try lagrangeInterpolation(shares: currentCombiShares, offset: 0)
let derivedPrivateKeyHex = derivedPrivateKey

guard Data(hexString: derivedPrivateKeyHex) != nil else {
continue
}
let decryptedPubKey = SECP256K1.privateToPublic(privateKey: Data(hex: derivedPrivateKeyHex.addLeading0sForLength64()) )?.toHexString()
print("decryptedPubKey", decryptedPubKey, derivedPrivateKey)
let decryptedPubKeyX = String(decryptedPubKey!.suffix(128).prefix(64))
let decryptedPubKeyY = String(decryptedPubKey!.suffix(64))
if decryptedPubKeyX == thresholdPublicKey.X.addLeading0sForLength64() && decryptedPubKeyY == thresholdPublicKey.Y.addLeading0sForLength64() {
returnedKey = derivedPrivateKey
break
}
}

return returnedKey

}


// MARK: - retrieveShare
// TODO: add importShare functionality later
Expand Down Expand Up @@ -370,7 +404,8 @@ extension TorusUtils {

if thresholdPublicKey?.X != nil && (thresholdNonceData != nil && thresholdNonceData?.pubNonce?.x != "" || verifierParams.extended_verifier_id != nil || isLegacyNetwork()) {
// Code block to execute if all conditions are true
var sharePromises = [String]()
var sharePkcs7 = [String]()
var shareZeroPadding = [String]()
var sessionTokenSigPromises = [String?]()
var sessionTokenPromises = [String?]()
var nodeIndexes = [Int]()
Expand Down Expand Up @@ -417,12 +452,16 @@ extension TorusUtils {
let binaryString = String(data: data, encoding: .ascii) ?? ""
let paddedBinaryString = binaryString.padding(toLength: 64, withPad: "0", startingAt: 0)
var decryptedShare = try decryptNodeData(eciesData: latestKey.shareMetadata, ciphertextHex: paddedBinaryString, privKey: sessionAuthKey)

sharePkcs7.append(decryptedShare.addLeading0sForLength64())
// temporary workaround on decrypt padding issue
if ( decryptedShare.count < 58 ) {
if ( decryptedShare.count < 64 ) {

decryptedShare = try decryptNodeData(eciesData: latestKey.shareMetadata, ciphertextHex: paddedBinaryString, privKey: sessionAuthKey, padding: .zeroPadding).addLeading0sForLength64()
shareZeroPadding.append(decryptedShare)
} else {
shareZeroPadding.append(decryptedShare)
}
sharePromises.append(decryptedShare)


} else {
os_log("retrieveShare - 0 keys returned from nodes", log: getTorusLogger(log: TorusUtilsLogger.core, type: .error), type: .error)
Expand Down Expand Up @@ -469,40 +508,25 @@ extension TorusUtils {
sessionTokenData.append(SessionToken(token: token, signature: signature!, node_pubx: nodePubX, node_puby: nodePubY))
}
}
let decryptedShares = sharePromises.enumerated().reduce(into: [ Int : String ]()) { acc, current in
let decryptedSharesPkcs7 = sharePkcs7.enumerated().reduce(into: [ Int : String ]()) { acc, current in
let (index, curr) = current
acc[nodeIndexes[index]] = curr
}

// run lagrange interpolation on all subsets, faster in the optimistic scenario than berlekamp-welch due to early exit
let allCombis = kCombinations(s: decryptedShares.count, k: 3)
var returnedKey: String? = nil

for j in 0..<allCombis.count {
let currentCombi = allCombis[j]
let currentCombiShares = decryptedShares.enumerated().reduce(into: [ Int : String ]()) { acc, current in
let (index, curr) = current
if (currentCombi.contains(index)) {
acc[curr.key] = curr.value
}
}
let derivedPrivateKey = try lagrangeInterpolation(shares: currentCombiShares, offset: 0)
let derivedPrivateKeyHex = derivedPrivateKey


guard Data(hexString: derivedPrivateKeyHex) != nil else {
continue
}
let decryptedPubKey = SECP256K1.privateToPublic(privateKey: Data(hex: derivedPrivateKey) )?.toHexString()

let decryptedPubKeyX = String(decryptedPubKey!.suffix(128).prefix(64))
let decryptedPubKeyY = String(decryptedPubKey!.suffix(64))
if decryptedPubKeyX == thresholdPublicKey?.X.addLeading0sForLength64() && decryptedPubKeyY == thresholdPublicKey?.Y.addLeading0sForLength64() {
returnedKey = derivedPrivateKey
break

var returnedKey = try reconstructKey(decryptedShares: decryptedSharesPkcs7, thresholdPublicKey: thresholdPublicKey!)

if (returnedKey == nil) {
let decryptedSharesZeroPadding = shareZeroPadding.enumerated().reduce(into: [ Int : String ]()) { acc, current in
let (index, curr) = current
acc[nodeIndexes[index]] = curr
}
returnedKey = try reconstructKey(decryptedShares: decryptedSharesZeroPadding, thresholdPublicKey: thresholdPublicKey!)

}


guard let oAuthKey = returnedKey else {
throw TorusUtilError.privateKeyDeriveFailed
}
Expand All @@ -515,7 +539,7 @@ extension TorusUtils {
throw TorusUtilError.privateKeyDeriveFailed
}

let oAuthPubKey = SECP256K1.privateToPublic(privateKey: derivedPrivateKeyData)?.toHexString()
let oAuthPubKey = SECP256K1.privateToPublic(privateKey: derivedPrivateKeyData.addLeading0sForLength64())?.toHexString()
let oauthPubKeyX = String(oAuthPubKey!.suffix(128).prefix(64))
let oauthPubKeyY = String(oAuthPubKey!.suffix(64))

Expand Down
3 changes: 2 additions & 1 deletion Tests/TorusUtilsTests/SapphireTest.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -430,7 +430,7 @@ final class SapphireTest: XCTestCase {
let verifierParams = VerifierParams(verifier_id: verifierID)
do {
let nodeDetails = try await get_fnd_and_tu_data(verifer: verifier, veriferID: verifierID)

let data = try await torus.retrieveShares(endpoints: endpoint.torusNodeEndpoints, torusNodePubs: nodeDetails.getTorusNodePub(),indexes: nodeDetails.getTorusIndexes(), verifier: verifier, verifierParams: verifierParams, idToken: hashedIDToken, extraParams: extraParams)

XCTAssertNotNil(data.finalKeyData?.evmAddress)
Expand All @@ -439,6 +439,7 @@ final class SapphireTest: XCTestCase {
XCTAssertEqual(data.metadata?.typeOfUser, .v2)
XCTAssertNotNil(data.metadata?.nonce)
XCTAssertEqual(data.metadata?.upgraded, false)

exp1.fulfill()
} catch let err {
XCTFail(err.localizedDescription)
Expand Down

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