// HashTransaction derives the network specific hash for the provided
// transaction using the network identified by the supplied passphrase. The
// resulting hash is the value that can be signed by stellar secret key to
// authorize the transaction identified by the hash to stellar validators.
func HashTransaction(tx *xdr.Transaction, passphrase string) ([32]byte, error) {
var txBytes bytes.Buffer
_, err := fmt.Fprintf(&txBytes, "%s", ID(passphrase))
if err != nil {
return [32]byte{}, errors.Wrap(err, "fprint network id failed")
}
_, err = xdr.Marshal(&txBytes, xdr.EnvelopeTypeEnvelopeTypeTx)
if err != nil {
return [32]byte{}, errors.Wrap(err, "marshal type failed")
}
_, err = xdr.Marshal(&txBytes, tx)
if err != nil {
return [32]byte{}, errors.Wrap(err, "marshal tx failed")
}
return hash.Hash(txBytes.Bytes()), nil
}
// ExampleLowLevelTransaction creates and signs a simple transaction, and then
// encodes it into a hex string capable of being submitted to stellar-core.
//
// It uses the low-level xdr facilities to create the transaction.
func ExampleLowLevelTransaction() {
skp := keypair.MustParse("SA26PHIKZM6CXDGR472SSGUQQRYXM6S437ZNHZGRM6QA4FOPLLLFRGDX")
dkp := keypair.MustParse("SBQHO2IMYKXAYJFCWGXC7YKLJD2EGDPSK3IUDHVJ6OOTTKLSCK6Z6POM")
asset, err := xdr.NewAsset(xdr.AssetTypeAssetTypeNative, nil)
if err != nil {
panic(err)
}
var destination xdr.AccountId
err = destination.SetAddress(dkp.Address())
if err != nil {
panic(err)
}
op := xdr.PaymentOp{
Destination: destination,
Asset: asset,
Amount: 50 * 10000000,
}
memo, err := xdr.NewMemo(xdr.MemoTypeMemoNone, nil)
var source xdr.AccountId
err = source.SetAddress(skp.Address())
if err != nil {
panic(err)
}
body, err := xdr.NewOperationBody(xdr.OperationTypePayment, op)
if err != nil {
panic(err)
}
tx := xdr.Transaction{
SourceAccount: source,
Fee: 10,
SeqNum: xdr.SequenceNumber(1),
Memo: memo,
Operations: []xdr.Operation{
{Body: body},
},
}
var txBytes bytes.Buffer
_, err = xdr.Marshal(&txBytes, tx)
if err != nil {
panic(err)
}
txHash := hash.Hash(txBytes.Bytes())
signature, err := skp.Sign(txHash[:])
if err != nil {
panic(err)
}
ds := xdr.DecoratedSignature{
Hint: skp.Hint(),
Signature: xdr.Signature(signature[:]),
}
txe := xdr.TransactionEnvelope{
Tx: tx,
Signatures: []xdr.DecoratedSignature{ds},
}
var txeBytes bytes.Buffer
_, err = xdr.Marshal(&txeBytes, txe)
if err != nil {
panic(err)
}
txeB64 := base64.StdEncoding.EncodeToString(txeBytes.Bytes())
fmt.Printf("tx base64: %s", txeB64)
// Output: tx base64: AAAAAAU08yUQ8sHqhY8j9mXWwERfHC/3cKFSe/spAr0rGtO2AAAACgAAAAAAAAABAAAAAAAAAAAAAAABAAAAAAAAAAEAAAAA+fnTe7/v4whpBUx96oj92jfZPz7S00l3O2xeyeqWIA0AAAAAAAAAAB3NZQAAAAAAAAAAASsa07YAAABAieruUIGcQH6RlQ+prYflPFU3nED2NvWhtaC+tgnKsqgiKURK4xo/W7EgH0+I6aQok52awbE+ksOxEQ5MLJ9eAw==
}
// ID returns the network ID derived from the provided passphrase. This value
// also happens to be the raw (i.e. not strkey encoded) secret key for the root
// account of the network.
func ID(passphrase string) [32]byte {
return hash.Hash([]byte(passphrase))
}