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BOLT 3,5: update weight calculations for revocation key hash in script.

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Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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Rusty Russell 2017-03-07 10:28:30 +10:30
parent a597738b94
commit 392008a7d3
2 changed files with 63 additions and 64 deletions
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62
03-transactions.md
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@ -258,8 +258,8 @@ Thus we use a simplified formula for *expected weight*, which assumes:
This gives us the following *expected weights* (details of the computation in [Appendix A](#appendix-a-expected-weights)): This gives us the following *expected weights* (details of the computation in [Appendix A](#appendix-a-expected-weights)):
Commitment weight: 724 + 172 * num-untrimmed-htlc-outputs Commitment weight: 724 + 172 * num-untrimmed-htlc-outputs
HTLC-timeout weight: 669 HTLC-timeout weight: 663
HTLC-success weight: 718 HTLC-success weight: 703
Note that we refer to the "base fee" for a commitment transaction in the requirements below, which is what the funder pays. The actual fee may be higher than the amount calculated here, due to rounding and trimmed outputs. Note that we refer to the "base fee" for a commitment transaction in the requirements below, which is what the funder pays. The actual fee may be higher than the amount calculated here, due to rounding and trimmed outputs.
@ -267,11 +267,11 @@ Note that we refer to the "base fee" for a commitment transaction in the require
The fee for an HTLC-timeout transaction MUST BE calculated to match: The fee for an HTLC-timeout transaction MUST BE calculated to match:
1. Multiply `feerate-per-kw` by 669 and divide by 1000 (rounding down). 1. Multiply `feerate-per-kw` by 663 and divide by 1000 (rounding down).
The fee for an HTLC-success transaction MUST BE calculated to match: The fee for an HTLC-success transaction MUST BE calculated to match:
1. Multiply `feerate-per-kw` by 718 and divide by 1000 (rounding down). 1. Multiply `feerate-per-kw` by 703 and divide by 1000 (rounding down).
The base fee for a commitment transaction MUST BE calculated to match: The base fee for a commitment transaction MUST BE calculated to match:
@ -288,8 +288,8 @@ For example, suppose that we have a `feerate-per-kw` of 5000, a `dust-limit-sato
* 2 offered HTLCs of 5000000 and 1000000 millisatoshis (5000 and 1000 satoshis) * 2 offered HTLCs of 5000000 and 1000000 millisatoshis (5000 and 1000 satoshis)
* 2 received HTLCs of 7000000 and 800000 millisatoshis (7000 and 800 satoshis) * 2 received HTLCs of 7000000 and 800000 millisatoshis (7000 and 800 satoshis)
The HTLC timeout transaction weight is 669, thus fee would be 3345 satoshis. The HTLC timeout transaction weight is 663, thus fee would be 3315 satoshis.
The HTLC success transaction weight is 718, thus fee would be 3590 satoshis The HTLC success transaction weight is 703, thus fee would be 3515 satoshis
The commitment transaction weight would be calculated as follows: The commitment transaction weight would be calculated as follows:
@ -607,13 +607,20 @@ Multiplying non-witness data by 4, this gives a weight of:
The *expected weight* of an HTLC transaction is calculated as follows: The *expected weight* of an HTLC transaction is calculated as follows:
accepted_htlc_script: 156 bytes accepted_htlc_script: 139 bytes
- OP_DUP: 1 byte
- OP_HASH160: 1 byte
- OP_DATA: 1 byte (revocationkey-hash length)
- revocationkey-hash: 20 bytes
- OP_EQUAL: 1 byte
- OP_IF: 1 byte
- OP_CHECKSIG: 1 byte
- OP_ELSE: 1 byte
- OP_DATA: 1 byte (remotekey length) - OP_DATA: 1 byte (remotekey length)
- remotekey: 33 bytes - remotekey: 33 bytes
- OP_SWAP: 1 byte - OP_SWAP: 1 byte
- OP_SIZE: 1 byte - OP_SIZE: 1 byte
- OP_DATA: 1 byte (32 length) - 32: 2 bytes
- 32: 1 byte
- OP_EQUAL: 1 byte - OP_EQUAL: 1 byte
- OP_IF: 1 byte - OP_IF: 1 byte
- OP_HASH160: 1 byte - OP_HASH160: 1 byte
@ -627,28 +634,24 @@ The *expected weight* of an HTLC transaction is calculated as follows:
- 2: 1 byte - 2: 1 byte
- OP_CHECKMULTISIG: 1 byte - OP_CHECKMULTISIG: 1 byte
- OP_ELSE: 1 byte - OP_ELSE: 1 byte
- OP_SIZE: 1 byte
- 0: 1 byte
- OP_EQUAL: 1 byte
- OP_IF: 1 byte
- OP_DROP: 1 byte - OP_DROP: 1 byte
- OP_DATA: 1 byte (locktime length) - OP_DATA: 1 byte (locktime length)
- locktime: 3 bytes - locktime: 3 bytes
- OP_CHECKLOCKTIMEVERIFY: 1 byte - OP_CHECKLOCKTIMEVERIFY: 1 byte
- OP_DROP: 1 byte - OP_DROP: 1 byte
- OP_CHECKSIG: 1 byte - OP_CHECKSIG: 1 byte
- OP_ELSE: 1 byte
- OP_SWAP: 1 byte
- 2: 1 byte
- OP_SWAP: 1 byte
- OP_DATA: 1 byte (revocationkey length)
- revocationkey: 33 bytes
- 2: 1 byte
- OP_CHECKMULTISIG: 1 byte
- OP_ENDIF: 1 byte - OP_ENDIF: 1 byte
- OP_ENDIF: 1 byte - OP_ENDIF: 1 byte
offered_htlc_script: 139 bytes offered_htlc_script: 133 bytes
- OP_DUP: 1 byte
- OP_HASH160: 1 byte
- OP_DATA: 1 byte (revocationkey-hash length)
- revocationkey-hash: 20 bytes
- OP_EQUAL: 1 byte
- OP_IF: 1 byte
- OP_CHECKSIG: 1 byte
- OP_ELSE: 1 byte
- OP_DATA: 1 byte (remotekey length) - OP_DATA: 1 byte (remotekey length)
- remotekey: 33 bytes - remotekey: 33 bytes
- OP_SWAP: 1 byte - OP_SWAP: 1 byte
@ -662,9 +665,7 @@ The *expected weight* of an HTLC transaction is calculated as follows:
- OP_SWAP: 1 byte - OP_SWAP: 1 byte
- OP_DATA: 1 byte (localkey length) - OP_DATA: 1 byte (localkey length)
- localkey: 33 bytes - localkey: 33 bytes
- OP_DATA: 1 byte (revocationkey length) - 2: 1 byte
- revocationkey: 33 bytes
- 3: 1 byte
- OP_CHECKMULTISIG: 1 byte - OP_CHECKMULTISIG: 1 byte
- OP_ELSE: 1 byte - OP_ELSE: 1 byte
- OP_HASH160: 1 byte - OP_HASH160: 1 byte
@ -673,8 +674,9 @@ The *expected weight* of an HTLC transaction is calculated as follows:
- OP_EQUALVERIFY: 1 byte - OP_EQUALVERIFY: 1 byte
- OP_CHECKSIG: 1 byte - OP_CHECKSIG: 1 byte
- OP_ENDIF: 1 byte - OP_ENDIF: 1 byte
- OP_ENDIF: 1 byte
timeout_witness: 291 bytes timeout_witness: 285 bytes
- number_of_witness_elements: 1 byte - number_of_witness_elements: 1 byte
- nil_length: 1 byte - nil_length: 1 byte
- sig_alice_length: 1 byte - sig_alice_length: 1 byte
@ -685,7 +687,7 @@ The *expected weight* of an HTLC transaction is calculated as follows:
- witness_script_length: 1 byte - witness_script_length: 1 byte
- witness_script (offered_htlc_script) - witness_script (offered_htlc_script)
success_witness: 340 bytes success_witness: 325 bytes
- number_of_witness_elements: 1 byte - number_of_witness_elements: 1 byte
- nil_length: 1 byte - nil_length: 1 byte
- sig_alice_length: 1 byte - sig_alice_length: 1 byte
@ -723,11 +725,11 @@ The *expected weight* of an HTLC transaction is calculated as follows:
- lock_time: 4 bytes - lock_time: 4 bytes
Multiplying non-witness data by 4, this gives a weight of 376. Adding Multiplying non-witness data by 4, this gives a weight of 376. Adding
the witness data for each case (291 + 2 for HTLC-timeout, 340 + 2 for the witness data for each case (285 + 2 for HTLC-timeout, 325 + 2 for
HTLC-success) gives a weight of: HTLC-success) gives a weight of:
669 (HTLC-timeout) 663 (HTLC-timeout)
718 (HTLC-success) 703 (HTLC-success)
# Appendix C: Funding Transaction Test Vectors # Appendix C: Funding Transaction Test Vectors

35
05-onchain.md
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@ -325,14 +325,14 @@ should cover this. [FIXME: May have to divide and conquer here, since they may b
There are three different scripts for penalty transactions, with the following witnesses weight (details of the computation in [Appendix A](#appendix-a-expected-weights)): There are three different scripts for penalty transactions, with the following witnesses weight (details of the computation in [Appendix A](#appendix-a-expected-weights)):
to_local_penalty_witness: 154 bytes to_local_penalty_witness: 154 bytes
offered_htlc_penalty_witness: 291 bytes offered_htlc_penalty_witness: 243 bytes
accepted_htlc_penalty_witness: 307 bytes accepted_htlc_penalty_witness: 249 bytes
The penalty txinput itself takes 41 bytes, thus has a weight of 164, making the weight of each input: The penalty txinput itself takes 41 bytes, thus has a weight of 164, making the weight of each input:
to_local_penalty_input_weight: 318 bytes to_local_penalty_input_weight: 318 bytes
offered_htlc_penalty_input_weight: 455 bytes offered_htlc_penalty_input_weight: 407 bytes
accepted_htlc_penalty_input_weight: 471 bytes accepted_htlc_penalty_input_weight: 413 bytes
The rest of the penalty transaction takes 4+3+1+8+1+34+4=55 bytes The rest of the penalty transaction takes 4+3+1+8+1+34+4=55 bytes
assuming it has a pay-to-witness-script-hash (the largest standard assuming it has a pay-to-witness-script-hash (the largest standard
@ -343,9 +343,9 @@ us to spend from the commitment transaction.
With a maximum standard weight of 400000: With a maximum standard weight of 400000:
max_num_htlcs = (400000 - 318 - 55) / 471 = 848 max_num_htlcs = (400000 - 318 - 55) / 413 = 967
Thus we could allow 424 HTLCs in each direction (with one output to-self) and still resolve it with a single penalty Thus we could allow 483 HTLCs in each direction (with one output to-self) and still resolve it with a single penalty
transaction. transaction.
# General Requirements # General Requirements
@ -402,35 +402,32 @@ The *expected weight* is calculated as follows:
The *expected weight* is calculated as follows (some calculations have already been made in [BOLT #3](03-transactions.md)): The *expected weight* is calculated as follows (some calculations have already been made in [BOLT #3](03-transactions.md)):
offered_htlc_script: 139 bytes offered_htlc_script: 133 bytes
offered_htlc_penalty_witness: 291 bytes offered_htlc_penalty_witness: 243 bytes
- number_of_witness_elements: 1 byte - number_of_witness_elements: 1 byte
- nil_length: 1 byte
- remote_sig_length: 1 byte
- remote_sig: 73 bytes
- revocation_sig_length: 1 byte - revocation_sig_length: 1 byte
- revocation_sig: 73 bytes - revocation_sig: 73 bytes
- nil_length: 1 byte - revocation_key_length: 1 byte
- revocation_key: 33 bytes
- witness_script_length: 1 byte - witness_script_length: 1 byte
- witness_script (to_local_script) - witness_script (offered_htlc_script)
## Expected weight of the received-htlc penalty transaction witness ## Expected weight of the received-htlc penalty transaction witness
The *expected weight* is calculated as follows (some calculations have already been made in [BOLT #3](03-transactions.md)): The *expected weight* is calculated as follows (some calculations have already been made in [BOLT #3](03-transactions.md)):
accepted_htlc_script: 156 bytes accepted_htlc_script: 139 bytes
accepted_htlc_penalty_witness: 307 bytes accepted_htlc_penalty_witness: 249 bytes
- number_of_witness_elements: 1 byte - number_of_witness_elements: 1 byte
- nil_length: 1 byte
- remote_sig_length: 1 byte
- remote_sig: 73 bytes
- revocation_sig_length: 1 byte - revocation_sig_length: 1 byte
- revocation_sig: 73 bytes - revocation_sig: 73 bytes
- revocation_key_length: 1 byte
- revocation_key: 33 bytes
- witness_script_length: 1 byte - witness_script_length: 1 byte
- witness_script (to_local_script) - witness_script (accepted_htlc_script)
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