tapir/applications/token_app.go

68 рядки
2.3 KiB
Go

package applications
import (
"encoding/json"
"git.openprivacy.ca/cwtch.im/tapir"
"git.openprivacy.ca/cwtch.im/tapir/primitives/privacypass"
"git.openprivacy.ca/openprivacy/log"
)
// TokenApplication provides Tokens for PoW
type TokenApplication struct {
TranscriptApp
TokenService *privacypass.TokenServer
Tokens []*privacypass.Token
}
// HasTokensCapability is granted once the client has obtained signed tokens
const HasTokensCapability = tapir.Capability("HasTokensCapability")
const numTokens = 10
// NewInstance should always return a new instantiation of the application.
func (tokenapp *TokenApplication) NewInstance() tapir.Application {
app := new(TokenApplication)
app.TokenService = tokenapp.TokenService
return app
}
// Init is run when the connection is first started.
func (tokenapp *TokenApplication) Init(connection tapir.Connection) {
tokenapp.Transcript().NewProtocol("token-app")
log.Debugf(tokenapp.Transcript().OutputTranscriptToAudit())
if connection.IsOutbound() {
tokens, blinded := privacypass.GenerateBlindedTokenBatch(numTokens)
data, _ := json.Marshal(blinded)
connection.Send(data)
var signedBatch privacypass.SignedBatchWithProof
err := json.Unmarshal(connection.Expect(), &signedBatch)
if err == nil {
verified := privacypass.UnblindSignedTokenBatch(tokens, blinded, signedBatch.SignedTokens, tokenapp.TokenService.Y, signedBatch.Proof, tokenapp.Transcript())
if verified {
log.Debugf("Successfully obtained signed tokens")
tokenapp.Tokens = tokens
connection.SetCapability(HasTokensCapability)
return
}
// This will close the connection by default and no tokens will be available.
// This usecase can be checked by the existing WaitForCapabilityOrClose() function using the HasTokensCapability
// If the connection closes without the HasTokensCapability then the error can be handled by whatever client needs it
log.Debugf("Failed to verify signed token batch")
}
return
}
// We are the server
var blinded []privacypass.BlindedToken
err := json.Unmarshal(connection.Expect(), &blinded)
if err == nil {
batchProof, err := tokenapp.TokenService.SignBlindedTokenBatch(blinded, tokenapp.Transcript())
if err != nil {
return
}
log.Debugf(tokenapp.Transcript().OutputTranscriptToAudit())
data, _ := json.Marshal(batchProof)
connection.Send(data)
return
}
}