Example #1
0
// TestIsUnspendable ensures the IsUnspendable function returns the expected
// results.
func TestIsUnspendable(t *testing.T) {
	t.Parallel()

	tests := []struct {
		name     string
		pkScript []byte
		expected bool
	}{
		{
			// Unspendable
			pkScript: []byte{0x6a, 0x04, 0x74, 0x65, 0x73, 0x74},
			expected: true,
		},
		{
			// Spendable
			pkScript: []byte{0x76, 0xa9, 0x14, 0x29, 0x95, 0xa0,
				0xfe, 0x68, 0x43, 0xfa, 0x9b, 0x95, 0x45,
				0x97, 0xf0, 0xdc, 0xa7, 0xa4, 0x4d, 0xf6,
				0xfa, 0x0b, 0x5c, 0x88, 0xac},
			expected: false,
		},
	}

	for i, test := range tests {
		res := txscript.IsUnspendable(test.pkScript)
		if res != test.expected {
			t.Errorf("TestIsUnspendable #%d failed: got %v want %v",
				i, res, test.expected)
			continue
		}
	}
}
Example #2
0
// isDust returns whether or not the passed transaction output amount is
// considered dust or not based on the passed minimum transaction relay fee.
// Dust is defined in terms of the minimum transaction relay fee.  In
// particular, if the cost to the network to spend coins is more than 1/3 of the
// minimum transaction relay fee, it is considered dust.
func isDust(txOut *wire.TxOut, minRelayTxFee btcutil.Amount) bool {
	// Unspendable outputs are considered dust.
	if txscript.IsUnspendable(txOut.PkScript) {
		return true
	}

	// The total serialized size consists of the output and the associated
	// input script to redeem it.  Since there is no input script
	// to redeem it yet, use the minimum size of a typical input script.
	//
	// Pay-to-pubkey-hash bytes breakdown:
	//
	//  Output to hash (34 bytes):
	//   8 value, 1 script len, 25 script [1 OP_DUP, 1 OP_HASH_160,
	//   1 OP_DATA_20, 20 hash, 1 OP_EQUALVERIFY, 1 OP_CHECKSIG]
	//
	//  Input with compressed pubkey (148 bytes):
	//   36 prev outpoint, 1 script len, 107 script [1 OP_DATA_72, 72 sig,
	//   1 OP_DATA_33, 33 compressed pubkey], 4 sequence
	//
	//  Input with uncompressed pubkey (180 bytes):
	//   36 prev outpoint, 1 script len, 139 script [1 OP_DATA_72, 72 sig,
	//   1 OP_DATA_65, 65 compressed pubkey], 4 sequence
	//
	// Pay-to-pubkey bytes breakdown:
	//
	//  Output to compressed pubkey (44 bytes):
	//   8 value, 1 script len, 35 script [1 OP_DATA_33,
	//   33 compressed pubkey, 1 OP_CHECKSIG]
	//
	//  Output to uncompressed pubkey (76 bytes):
	//   8 value, 1 script len, 67 script [1 OP_DATA_65, 65 pubkey,
	//   1 OP_CHECKSIG]
	//
	//  Input (114 bytes):
	//   36 prev outpoint, 1 script len, 73 script [1 OP_DATA_72,
	//   72 sig], 4 sequence
	//
	// Theoretically this could examine the script type of the output script
	// and use a different size for the typical input script size for
	// pay-to-pubkey vs pay-to-pubkey-hash inputs per the above breakdowns,
	// but the only combinination which is less than the value chosen is
	// a pay-to-pubkey script with a compressed pubkey, which is not very
	// common.
	//
	// The most common scripts are pay-to-pubkey-hash, and as per the above
	// breakdown, the minimum size of a p2pkh input script is 148 bytes.  So
	// that figure is used.
	totalSize := txOut.SerializeSize() + 148

	// The output is considered dust if the cost to the network to spend the
	// coins is more than 1/3 of the minimum free transaction relay fee.
	// minFreeTxRelayFee is in Satoshi/KB, so multiply by 1000 to
	// convert to bytes.
	//
	// Using the typical values for a pay-to-pubkey-hash transaction from
	// the breakdown above and the default minimum free transaction relay
	// fee of 1000, this equates to values less than 546 satoshi being
	// considered dust.
	//
	// The following is equivalent to (value/totalSize) * (1/3) * 1000
	// without needing to do floating point math.
	return txOut.Value*1000/(3*int64(totalSize)) < int64(minRelayTxFee)
}