Maximum standard input script size

Question

What is the maximum size for an input script so to be considered standard ? Looking at the Bitcoin Core source code it appears to be 10'000 byte, however reading here and there, it appears to be 1650 byte. If that's the case, if the input script is redeeming a P2SH, is the size of the redeem script (520 byte) to be considered in the count, or not ? Thank you very much !

Answer 1

By input script, if you mean scriptSig, the max standard scriptSig can be up to 1650 bytes.

See policy.cpp :

// Biggest 'standard' txin is a 15-of-15 P2SH multisig with compressed
// keys (remember the 520 byte limit on redeemScript size). That works
// out to a (15*(33+1))+3=513 byte redeemScript, 513+1+15*(73+1)+3=1627
// bytes of scriptSig, which we round off to 1650 bytes for some minor
// future-proofing. That's also enough to spend a 20-of-20
// CHECKMULTISIG scriptPubKey, though such a scriptPubKey is not
// considered standard.
if (txin.scriptSig.size() > 1650) {
    reason = "scriptsig-size";
    return false;
}