First cut of Token Board
This commit is contained in:
parent
5b64c2d708
commit
345d11f506
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@ -3,3 +3,4 @@ vendor/
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/tor/
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coverage.out
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/testing/tor/
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/applications/tor/
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@ -0,0 +1,192 @@
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package applications
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import (
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"cwtch.im/tapir"
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"cwtch.im/tapir/primitives"
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"cwtch.im/tapir/primitives/privacypass"
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"encoding/json"
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"git.openprivacy.ca/openprivacy/libricochet-go/log"
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)
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// TokenBoardApp defines a Tapir Meta=App which provides a global cryptographic transcript
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type TokenBoardApp struct {
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AuthApp
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connection tapir.Connection
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TokenService *privacypass.TokenServer
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AuditableStore *primitives.AuditableStore
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paymentHandler privacypass.TokenPaymentHandler
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handler TokenBoardAppHandler
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}
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// TokenBoardAppHandler allows clients to react to specific events.
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type TokenBoardAppHandler interface {
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HandleNewMessages(previousLastCommit []byte)
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}
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// NewTokenBoardClient generates a new Client for Token Board
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func NewTokenBoardClient(store *primitives.AuditableStore, handler TokenBoardAppHandler, paymentHandler privacypass.TokenPaymentHandler) tapir.Application {
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tba := new(TokenBoardApp)
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tba.TokenService = nil
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tba.AuditableStore = store
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tba.handler = handler
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tba.paymentHandler = paymentHandler
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return tba
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}
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// NewTokenBoardServer generates new Server for Token Board
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func NewTokenBoardServer(tokenService *privacypass.TokenServer, store *primitives.AuditableStore) tapir.Application {
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tba := new(TokenBoardApp)
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tba.TokenService = tokenService
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tba.AuditableStore = store
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return tba
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}
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// NewInstance creates a new TokenBoardApp
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func (ta *TokenBoardApp) NewInstance() tapir.Application {
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tba := new(TokenBoardApp)
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tba.TokenService = ta.TokenService
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tba.AuditableStore = ta.AuditableStore
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tba.handler = ta.handler
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tba.paymentHandler = ta.paymentHandler
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return tba
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}
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// Init initializes the cryptographic TokenBoardApp
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func (ta *TokenBoardApp) Init(connection tapir.Connection) {
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ta.AuthApp.Init(connection)
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if connection.HasCapability(AuthCapability) {
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ta.connection = connection
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// If we are a server, now we can start listening for inbound messages
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if ta.connection.IsOutbound() {
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go ta.listen(ta.clientSwitch)
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} else {
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go ta.listen(ta.serverSwitch)
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}
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return
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}
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connection.Close()
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}
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// TokenBoardMessage encapsulates the application protocol
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type TokenBoardMessage struct {
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MessageType string
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PostRequest PostRequest `json:",omitempty"`
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PostResult PostResult `json:",omitempty"`
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ReplayRequest ReplayRequest `json:",omitempty"`
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ReplayResponse ReplayResponse `json:",omitempty"`
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}
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// ReplayRequest requests a reply from the given Commit
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type ReplayRequest struct {
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LastCommit []byte
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}
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// PostRequest requests to post the message to the board with the given token
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type PostRequest struct {
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Token privacypass.SpentToken
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Message primitives.Message
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}
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// PostResult returns the success of a given post attempt
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type PostResult struct {
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Success bool
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Proof primitives.SignedProof
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}
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// ReplayResponse is sent by the server before a stream of replayed messages
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type ReplayResponse struct {
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NumMessages int
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}
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func (ta *TokenBoardApp) clientSwitch(message TokenBoardMessage) {
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switch message.MessageType {
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case "PostResult":
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log.Debugf("Post result: %x", message.PostResult.Proof)
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case "ReplayResponse":
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var state primitives.State
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log.Debugf("Replaying %v Messages...", message.ReplayResponse.NumMessages)
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lastCommit := ta.AuditableStore.LatestCommit
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for i := 0; i < message.ReplayResponse.NumMessages; i++ {
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message := ta.connection.Expect()
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state.Messages = append(state.Messages, message)
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}
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data := ta.connection.Expect()
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var signedProof primitives.SignedProof
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json.Unmarshal(data, &signedProof)
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err := ta.AuditableStore.MergeState(state, signedProof)
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if err == nil {
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log.Debugf("Successfully updated Auditable Store")
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ta.handler.HandleNewMessages(lastCommit)
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} else {
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log.Debugf("Error updating Auditable Store %v", err)
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}
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}
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}
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func (ta *TokenBoardApp) serverSwitch(message TokenBoardMessage) {
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switch message.MessageType {
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case "PostRequest":
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postrequest := message.PostRequest
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log.Debugf("Received a Post Message Request: %x %x", postrequest.Token, postrequest.Message)
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ta.postMessageRequest(postrequest.Token, postrequest.Message)
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case "ReplayRequest":
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state, proof := ta.AuditableStore.GetState()
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response, _ := json.Marshal(TokenBoardMessage{MessageType: "ReplayResponse", ReplayResponse: ReplayResponse{len(state.Messages)}})
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ta.connection.Send(response)
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for _, message := range state.Messages {
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ta.connection.Send(message)
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}
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data, _ := json.Marshal(proof)
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ta.connection.Send(data)
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}
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}
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func (ta *TokenBoardApp) listen(switchFn func(TokenBoardMessage)) {
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for {
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data := ta.connection.Expect()
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if len(data) == 0 {
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return // connection is closed
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}
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var message TokenBoardMessage
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json.Unmarshal(data, &message)
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log.Debugf("Received a Message: %v", message)
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switchFn(message)
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}
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}
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// Replay posts a Replay Message to the server.
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func (ta *TokenBoardApp) Replay() {
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data, _ := json.Marshal(TokenBoardMessage{MessageType: "ReplayRequest"})
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ta.connection.Send(data)
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}
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// PurchaseTokens purchases the given number of tokens from the server (using the provided payment handler)
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func (ta *TokenBoardApp) PurchaseTokens(num int) {
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ta.paymentHandler.MakePayment(num)
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}
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// Post sends a Post Request to the server
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func (ta *TokenBoardApp) Post(message primitives.Message) bool {
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token, err := ta.paymentHandler.NextToken(message)
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if err == nil {
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data, _ := json.Marshal(TokenBoardMessage{MessageType: "PostRequest", PostRequest: PostRequest{Token: token, Message: message}})
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ta.connection.Send(data)
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return true
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}
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return false
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}
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func (ta *TokenBoardApp) postMessageRequest(token privacypass.SpentToken, message primitives.Message) {
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if ta.TokenService.IsValid(token, message) {
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log.Debugf("Token is valid")
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signedproof := ta.AuditableStore.Add(message)
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data, _ := json.Marshal(TokenBoardMessage{MessageType: "PostResult", PostResult: PostResult{true, signedproof}})
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ta.connection.Send(data)
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} else {
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log.Debugf("Attempt to spend an invalid token")
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data, _ := json.Marshal(TokenBoardMessage{MessageType: "PostResult", PostResult: PostResult{false, primitives.SignedProof{}}})
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ta.connection.Send(data)
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}
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}
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@ -0,0 +1,118 @@
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package applications
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import (
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"cwtch.im/tapir"
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"cwtch.im/tapir/networks/tor"
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"cwtch.im/tapir/primitives"
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"cwtch.im/tapir/primitives/core"
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"cwtch.im/tapir/primitives/privacypass"
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"errors"
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"git.openprivacy.ca/openprivacy/libricochet-go/connectivity"
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"git.openprivacy.ca/openprivacy/libricochet-go/log"
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"runtime"
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"sync"
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"testing"
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"time"
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)
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type Handler struct {
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Store *primitives.AuditableStore
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}
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func (h Handler) HandleNewMessages(previousLastCommit []byte) {
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log.Debugf("Handling Messages After %x", previousLastCommit)
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messages := h.Store.GetMessagesAfter(previousLastCommit)
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for _, message := range messages {
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log.Debugf("Message %s", message)
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}
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}
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type FreePaymentHandler struct {
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tokens []*privacypass.Token
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TokenService *privacypass.TokenServer
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}
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func (fph *FreePaymentHandler) MakePayment(int) {
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tokens, blindedTokens := privacypass.GenerateBlindedTokenBatch(10)
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// Obtained some signed tokens, in reality these would be bought and paid for through some other mechanism.
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clientTranscript := core.NewTranscript("privacyPass")
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serverTranscript := core.NewTranscript("privacyPass")
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signedTokens, proof := fph.TokenService.SignBlindedTokenBatch(blindedTokens, serverTranscript)
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privacypass.UnblindSignedTokenBatch(tokens, blindedTokens, signedTokens, fph.TokenService.Y, proof, clientTranscript)
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fph.tokens = append(fph.tokens, tokens...)
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}
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func (fph *FreePaymentHandler) NextToken(data []byte) (privacypass.SpentToken, error) {
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if len(fph.tokens) == 0 {
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return privacypass.SpentToken{}, errors.New("No more tokens")
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}
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token := fph.tokens[0]
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fph.tokens = fph.tokens[1:]
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return token.SpendToken(data), nil
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}
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func TestTokenBoardApp(t *testing.T) {
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// numRoutinesStart := runtime.NumGoroutine()
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log.SetLevel(log.LevelDebug)
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log.Infof("Number of goroutines open at start: %d", runtime.NumGoroutine())
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// Connect to Tor
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var acn connectivity.ACN
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acn, _ = connectivity.StartTor("./", "")
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acn.WaitTillBootstrapped()
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// Generate Server Key
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sid, sk := primitives.InitializeEphemeralIdentity()
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tokenService := privacypass.NewTokenServer()
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serverAuditableStore := new(primitives.AuditableStore)
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serverAuditableStore.Init(sid)
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clientAuditableStore := new(primitives.AuditableStore)
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clientAuditableStore.Init(sid)
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// Init the Server running the Simple App.
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var service tapir.Service
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service = new(tor.BaseOnionService)
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service.Init(acn, sk, &sid)
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// Goroutine Management
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sg := new(sync.WaitGroup)
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sg.Add(1)
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go func() {
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service.Listen(NewTokenBoardServer(&tokenService, serverAuditableStore))
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sg.Done()
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}()
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time.Sleep(time.Second * 30)
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id, sk := primitives.InitializeEphemeralIdentity()
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var client tapir.Service
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client = new(tor.BaseOnionService)
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client.Init(acn, sk, &id)
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client.Connect(sid.Hostname(), NewTokenBoardClient(clientAuditableStore, Handler{Store: clientAuditableStore}, &FreePaymentHandler{TokenService: &tokenService}))
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client.WaitForCapabilityOrClose(sid.Hostname(), AuthCapability)
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conn, _ := client.GetConnection(sid.Hostname())
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tba, _ := conn.App().(*TokenBoardApp)
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tba.PurchaseTokens(10)
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tba.Post([]byte("HELLO 1"))
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tba.Post([]byte("HELLO 2"))
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tba.Post([]byte("HELLO 3"))
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tba.Post([]byte("HELLO 4"))
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tba.Post([]byte("HELLO 5"))
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tba.Replay()
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tba.Post([]byte("HELLO 6"))
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tba.Post([]byte("HELLO 7"))
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tba.Post([]byte("HELLO 8"))
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tba.Post([]byte("HELLO 9"))
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tba.Post([]byte("HELLO 10"))
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tba.Replay()
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if tba.Post([]byte("HELLO 11")) {
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t.Errorf("Post should have failed.")
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}
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time.Sleep(time.Second * 60)
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}
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@ -1,22 +1,25 @@
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package primitives
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import (
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"crypto/subtle"
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"cwtch.im/tapir/primitives/core"
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"encoding/base64"
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"errors"
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"golang.org/x/crypto/ed25519"
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"sync"
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)
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// SignedProof encapsulates a signed proof
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type SignedProof []byte
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type SignedProof struct {
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Commit []byte
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Proof []byte
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}
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// Message encapsulates a message for more readable code.
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type Message []byte
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// State defines an array of messages.
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type State struct {
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message []Message
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Messages []Message
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}
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// AuditableStore defines a cryptographically secure & auditable transcript of messages sent from multiple
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@ -25,50 +28,64 @@ type AuditableStore struct {
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state State
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identity Identity
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transcript *core.Transcript
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latestCommit []byte
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commits map[string]bool
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LatestCommit []byte
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commits map[string]int
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mutex sync.Mutex
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}
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// Init initializes an auditable store
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func (as *AuditableStore) Init(identity Identity) {
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as.identity = identity
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as.transcript = core.NewTranscript("auditable-data-store")
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as.commits = make(map[string]bool)
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as.commits = make(map[string]int)
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}
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// Add adds a message to the auditable store
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func (as *AuditableStore) Add(message Message, latestCommit []byte) ([]byte, SignedProof, error) {
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if subtle.ConstantTimeCompare(latestCommit, as.latestCommit) == 1 {
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as.state.message = append(as.state.message, message)
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as.transcript.AddToTranscript("new-message", message)
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as.latestCommit = as.identity.Sign(as.transcript.CommitToTranscript("commit"))
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return as.latestCommit, as.identity.Sign(as.latestCommit), nil
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}
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// this prevents multiple clients updating at the same time and will likely cause retry storms.
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return nil, nil, errors.New("attempt to append out of date transcript")
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func (as *AuditableStore) Add(message Message) SignedProof {
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as.mutex.Lock()
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defer as.mutex.Unlock()
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as.state.Messages = append(as.state.Messages, message)
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as.transcript.AddToTranscript("new-message", message)
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as.LatestCommit = as.identity.Sign(as.transcript.CommitToTranscript("commit"))
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return SignedProof{as.LatestCommit, as.identity.Sign(as.LatestCommit)}
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}
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// GetState returns the current auditable state
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func (as *AuditableStore) GetState() (State, []byte, SignedProof) {
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return as.state, as.latestCommit, as.identity.Sign(as.latestCommit)
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func (as *AuditableStore) GetState() (State, SignedProof) {
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as.mutex.Lock()
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defer as.mutex.Unlock()
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return as.state, SignedProof{as.LatestCommit, as.identity.Sign(as.LatestCommit)}
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}
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// GetMessagesAfter provides access to messages after the given commit.
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func (as *AuditableStore) GetMessagesAfter(latestCommit []byte) []Message {
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as.mutex.Lock()
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defer as.mutex.Unlock()
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index, ok := as.commits[base64.StdEncoding.EncodeToString(latestCommit)]
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if !ok && len(latestCommit) == 32 {
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return []Message{}
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} else if len(latestCommit) == 0 {
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index = -1
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}
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return as.state.Messages[index+1:]
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}
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// MergeState merges a given state onto our state, first verifying that the two transcripts align
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func (as *AuditableStore) MergeState(state State, signedStateProof SignedProof, key ed25519.PublicKey) error {
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next := len(as.state.message)
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for _, m := range state.message[next:] {
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as.state.message = append(as.state.message, m)
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func (as *AuditableStore) MergeState(state State, signedStateProof SignedProof) error {
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next := len(as.state.Messages)
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for i, m := range state.Messages[next:] {
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as.state.Messages = append(as.state.Messages, m)
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// We reconstruct the transcript
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as.transcript.AddToTranscript("new-message", m)
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as.latestCommit = as.identity.Sign(as.transcript.CommitToTranscript("commit"))
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as.commits[base64.StdEncoding.EncodeToString(as.latestCommit)] = true
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as.LatestCommit = as.identity.Sign(as.transcript.CommitToTranscript("commit"))
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as.commits[base64.StdEncoding.EncodeToString(as.LatestCommit)] = next + i
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}
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// verify that our state matches the servers signed state
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// this is *not* a security check, as a rogue server can simply sign any state
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// however committing to a state allows us to build fraud proofs for malicious servers later on.
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if ed25519.Verify(key, as.latestCommit, signedStateProof) == false {
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if ed25519.Verify(as.identity.PublicKey(), as.LatestCommit, signedStateProof.Proof) == false {
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return errors.New("state is not consistent, the server is malicious")
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}
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return nil
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@ -84,16 +101,16 @@ func (as *AuditableStore) MergeState(state State, signedStateProof SignedProof,
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// If, after syncing, the FraudProof still validates, then the server must be malicious.
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// the information revealed by publicizing a fraud proof is minimal it only reveals the inconsistent transcript commit
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// and not the cause (which could be reordered messages, dropped messages, additional messages or any combination)
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func (as *AuditableStore) VerifyFraudProof(commit []byte, signedFraudProof SignedProof, key ed25519.PublicKey) (bool, error) {
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func (as *AuditableStore) VerifyFraudProof(signedFraudProof SignedProof, key ed25519.PublicKey) (bool, error) {
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if ed25519.Verify(key, commit, signedFraudProof) == false {
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if ed25519.Verify(key, signedFraudProof.Commit, signedFraudProof.Proof) == false {
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// This could happen due to misuse of this function (trying to verify a proof with the wrong public key)
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// This could happen if the server lies to us and submits a fake state proof, however we cannot use this to
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// prove that the server is acting maliciously
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return false, errors.New("signed proof has not been signed by the given public key")
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}
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_, exists := as.commits[base64.StdEncoding.EncodeToString(commit)]
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_, exists := as.commits[base64.StdEncoding.EncodeToString(signedFraudProof.Commit)]
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if !exists {
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// We have a message signed by the server which verifies that a message was inserted into the state at a given index
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||||
// However this directly contradicts our version of the state.
|
||||
|
|
|
@ -12,22 +12,22 @@ func TestAuditableStore(t *testing.T) {
|
|||
as.Init(serverID)
|
||||
vs.Init(serverID) // This doesn't do anything
|
||||
|
||||
as.Add([]byte("Hello World"), as.latestCommit)
|
||||
state, _, proof := as.GetState()
|
||||
as.Add([]byte("Hello World"))
|
||||
state, proof := as.GetState()
|
||||
|
||||
if vs.MergeState(state, proof, serverID.PublicKey()) != nil {
|
||||
if vs.MergeState(state, proof) != nil {
|
||||
t.Fatalf("Fraud Proof Failed on Honest Proof")
|
||||
}
|
||||
|
||||
commit, fraudProof, _ := as.Add([]byte("Hello World 2"), as.latestCommit)
|
||||
fraudProof := as.Add([]byte("Hello World 2"))
|
||||
|
||||
// If you comment these out it simulates a lying server.
|
||||
state, _, proof = as.GetState()
|
||||
if vs.MergeState(state, proof, serverID.PublicKey()) != nil {
|
||||
state, proof = as.GetState()
|
||||
if vs.MergeState(state, proof) != nil {
|
||||
t.Fatalf("Fraud Proof Failed on Honest Proof")
|
||||
}
|
||||
|
||||
fraud, err := vs.VerifyFraudProof(commit, fraudProof, serverID.PublicKey())
|
||||
fraud, err := vs.VerifyFraudProof(fraudProof, serverID.PublicKey())
|
||||
|
||||
if err != nil {
|
||||
t.Fatalf("Error validated fraud proof: %v", err)
|
||||
|
|
|
@ -5,6 +5,7 @@ import (
|
|||
"crypto/rand"
|
||||
"cwtch.im/tapir/primitives/core"
|
||||
"fmt"
|
||||
"git.openprivacy.ca/openprivacy/libricochet-go/log"
|
||||
"github.com/bwesterb/go-ristretto"
|
||||
"golang.org/x/crypto/sha3"
|
||||
)
|
||||
|
@ -29,10 +30,16 @@ type SignedToken struct {
|
|||
|
||||
// SpentToken encapsulates the parameters needed to spend a Token
|
||||
type SpentToken struct {
|
||||
t []byte
|
||||
T []byte
|
||||
MAC []byte
|
||||
}
|
||||
|
||||
// TokenPaymentHandler defines an interface with external payment processors
|
||||
type TokenPaymentHandler interface {
|
||||
MakePayment(int)
|
||||
NextToken(data []byte) (SpentToken, error)
|
||||
}
|
||||
|
||||
// GenBlindedToken initializes the Token
|
||||
// GenToken() & Blind()
|
||||
func (t *Token) GenBlindedToken() BlindedToken {
|
||||
|
@ -41,6 +48,7 @@ func (t *Token) GenBlindedToken() BlindedToken {
|
|||
t.r = new(ristretto.Scalar).Rand()
|
||||
|
||||
Ht := sha3.Sum256(t.t)
|
||||
log.Debugf("token: %x", Ht)
|
||||
T := new(ristretto.Point).SetElligator(&Ht)
|
||||
P := new(ristretto.Point).ScalarMult(T, t.r)
|
||||
return BlindedToken{P}
|
||||
|
|
|
@ -2,6 +2,7 @@ package privacypass
|
|||
|
||||
import (
|
||||
"cwtch.im/tapir/primitives/core"
|
||||
"git.openprivacy.ca/openprivacy/libricochet-go/log"
|
||||
"testing"
|
||||
)
|
||||
|
||||
|
@ -30,6 +31,7 @@ func TestToken_SpendToken(t *testing.T) {
|
|||
}
|
||||
|
||||
func TestGenerateBlindedTokenBatch(t *testing.T) {
|
||||
log.SetLevel(log.LevelDebug)
|
||||
server := NewTokenServer()
|
||||
|
||||
clientTranscript := core.NewTranscript("privacyPass")
|
||||
|
|
|
@ -5,21 +5,24 @@ import (
|
|||
"cwtch.im/tapir/primitives/core"
|
||||
"encoding/hex"
|
||||
"fmt"
|
||||
"git.openprivacy.ca/openprivacy/libricochet-go/log"
|
||||
"github.com/bwesterb/go-ristretto"
|
||||
"golang.org/x/crypto/sha3"
|
||||
"sync"
|
||||
)
|
||||
|
||||
// TokenServer implements a token server.
|
||||
type TokenServer struct {
|
||||
k *ristretto.Scalar
|
||||
Y *ristretto.Point
|
||||
seen map[string]bool
|
||||
k *ristretto.Scalar
|
||||
Y *ristretto.Point
|
||||
seen map[string]bool
|
||||
mutex sync.Mutex
|
||||
}
|
||||
|
||||
// NewTokenServer generates a new TokenServer (used mostly for testing with ephemeral instances)
|
||||
func NewTokenServer() TokenServer {
|
||||
k := new(ristretto.Scalar).Rand()
|
||||
return TokenServer{k, new(ristretto.Point).ScalarMultBase(k), make(map[string]bool)}
|
||||
return TokenServer{k, new(ristretto.Point).ScalarMultBase(k), make(map[string]bool), sync.Mutex{}}
|
||||
}
|
||||
|
||||
// SignBlindedToken calculates kP for the given BlindedToken P
|
||||
|
@ -57,18 +60,23 @@ func (ts *TokenServer) constructBatchProof(blindedTokens []BlindedToken, signedT
|
|||
|
||||
// IsValid returns true a SpentToken is valid and has never been spent before, false otherwise.
|
||||
func (ts *TokenServer) IsValid(token SpentToken, data []byte) bool {
|
||||
if _, spent := ts.seen[hex.EncodeToString(token.t)]; spent {
|
||||
log.Debugf("data: [%s]", data)
|
||||
ts.mutex.Lock()
|
||||
defer ts.mutex.Unlock() // We only want 1 client at a time redeeming tokens to prevent double-spends
|
||||
if _, spent := ts.seen[hex.EncodeToString(token.T)]; spent {
|
||||
return false
|
||||
}
|
||||
Ht := sha3.Sum256(token.t)
|
||||
Ht := sha3.Sum256(token.T)
|
||||
log.Debugf("token: %x", Ht)
|
||||
T := new(ristretto.Point).SetElligator(&Ht)
|
||||
W := new(ristretto.Point).ScalarMult(T, ts.k)
|
||||
key := sha3.Sum256(append(token.t, W.Bytes()...))
|
||||
key := sha3.Sum256(append(token.T, W.Bytes()...))
|
||||
mac := hmac.New(sha3.New512, key[:])
|
||||
K := mac.Sum(data)
|
||||
log.Debugf("mac: \n%x\nK:%x\n", token.MAC, K)
|
||||
result := hmac.Equal(token.MAC, K)
|
||||
if result == true {
|
||||
ts.seen[hex.EncodeToString(token.t)] = true
|
||||
ts.seen[hex.EncodeToString(token.T)] = true
|
||||
}
|
||||
return result
|
||||
}
|
||||
|
|
Loading…
Reference in New Issue