100 lines
2.4 KiB
Go
100 lines
2.4 KiB
Go
package client
|
|
|
|
import (
|
|
"fmt"
|
|
"math"
|
|
"time"
|
|
|
|
"github.com/fiatjaf/opentimestamps"
|
|
"github.com/btcsuite/btcd/rpcclient"
|
|
)
|
|
|
|
// A BitcoinAttestationVerifier uses a bitcoin RPC connection to verify bitcoin
|
|
// headers.
|
|
type BitcoinAttestationVerifier struct {
|
|
btcrpcClient *rpcclient.Client
|
|
}
|
|
|
|
func NewBitcoinAttestationVerifier(
|
|
c *rpcclient.Client,
|
|
) *BitcoinAttestationVerifier {
|
|
return &BitcoinAttestationVerifier{c}
|
|
}
|
|
|
|
// VerifyAttestation checks a BitcoinAttestation using a given hash digest. It
|
|
// returns the time of the block if the verification succeeds, an error
|
|
// otherwise.
|
|
func (v *BitcoinAttestationVerifier) VerifyAttestation(
|
|
digest []byte, a *opentimestamps.BitcoinAttestation,
|
|
) (*time.Time, error) {
|
|
if a.Height > math.MaxInt64 {
|
|
return nil, fmt.Errorf("illegal block height")
|
|
}
|
|
blockHash, err := v.btcrpcClient.GetBlockHash(int64(a.Height))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
h, err := v.btcrpcClient.GetBlockHeader(blockHash)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
merkleRootBytes := h.MerkleRoot[:]
|
|
err = a.VerifyAgainstBlockHash(digest, merkleRootBytes)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
utc := h.Timestamp.UTC()
|
|
|
|
return &utc, nil
|
|
}
|
|
|
|
// A BitcoinVerification is the result of verifying a BitcoinAttestation
|
|
type BitcoinVerification struct {
|
|
Timestamp *opentimestamps.Timestamp
|
|
Attestation *opentimestamps.BitcoinAttestation
|
|
AttestationTime *time.Time
|
|
Error error
|
|
}
|
|
|
|
// BitcoinVerifications returns the all bitcoin attestation results for the
|
|
// timestamp.
|
|
func (v *BitcoinAttestationVerifier) BitcoinVerifications(
|
|
t *opentimestamps.Timestamp,
|
|
) (res []BitcoinVerification) {
|
|
t.Walk(func(ts *opentimestamps.Timestamp) {
|
|
for _, att := range ts.Attestations {
|
|
btcAtt, ok := att.(*opentimestamps.BitcoinAttestation)
|
|
if !ok {
|
|
continue
|
|
}
|
|
attTime, err := v.VerifyAttestation(ts.Message, btcAtt)
|
|
res = append(res, BitcoinVerification{
|
|
Timestamp: ts,
|
|
Attestation: btcAtt,
|
|
AttestationTime: attTime,
|
|
Error: err,
|
|
})
|
|
}
|
|
})
|
|
return res
|
|
}
|
|
|
|
// Verify returns the earliest bitcoin-attested time, or nil if none can be
|
|
// found or verified successfully.
|
|
func (v *BitcoinAttestationVerifier) Verify(
|
|
t *opentimestamps.Timestamp,
|
|
) (ret *time.Time, err error) {
|
|
res := v.BitcoinVerifications(t)
|
|
for _, r := range res {
|
|
if r.Error != nil {
|
|
err = r.Error
|
|
continue
|
|
}
|
|
if ret == nil || r.AttestationTime.Before(*ret) {
|
|
ret = r.AttestationTime
|
|
}
|
|
}
|
|
return
|
|
}
|