diff options
Diffstat (limited to 'bip-0158.mediawiki')
| -rw-r--r-- | bip-0158.mediawiki | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/bip-0158.mediawiki b/bip-0158.mediawiki index 08e542a..535ffd9 100644 --- a/bip-0158.mediawiki +++ b/bip-0158.mediawiki @@ -279,7 +279,7 @@ following items for each transaction in a block: * The scriptPubKey of each output, aside from all <code>OP_RETURN</code> output scripts. -Any "nil" items MUST NOT be included into the final set of filter elements. +Any "nil" items MUST NOT be included into the final set of filter elements. We exclude all <code>OP_RETURN</code> outputs in order to allow filters to easily be committed to in the future via a soft-fork. A likely area for future @@ -302,11 +302,12 @@ setting <code>M=1.497137 * 2^P</code> is close to optimal Empirical analysis also shows that was chosen as these parameters minimize the bandwidth utilized, considering both the expected number of blocks downloaded -due to false positives and the size of the filters themselves. +due to false positives and the size of the filters themselves. -The parameter <code>k</code> MUST be set to the first 16 bytes of the hash of -the block for which the filter is constructed. This ensures the key is -deterministic while still varying from block to block. +The parameter <code>k</code> MUST be set to the first 16 bytes of the hash +(in standard little-endian representation) of the block for which the filter is +constructed. This ensures the key is deterministic while still varying from +block to block. Since the value <code>N</code> is required to decode a GCS, a serialized GCS includes it as a prefix, written as a <code>CompactSize</code>. Thus, the @@ -432,7 +433,7 @@ gcs_match_any(key: [16]byte, compressed_set: []byte, targets: [][]byte, P: uint, == Appendix C: Test Vectors == -Test vectors for a P value of 20 on five testnet blocks, including the filters and filter headers, can be found [[bip-0158/testnet-20.csv|here]]. The code to generate these vectors for P values of 1 through 32 can be found [[bip-0158/gentestvectors.go|here]]. +Test vectors for basic block filters on five testnet blocks, including the filters and filter headers, can be found [[bip-0158/testnet-19.json|here]]. The code to generate them can be found [[bip-0158/gentestvectors.go|here]]. == References == |