covid19/dp3t-documents
covid19/dp3t-documents
1
0
Fork 0
mirror of https://github.com/DP-3T/documents.git synced 2024-11-11 21:28:50 +01:00
Code Releases Activity

Updated cf format

Browse Source
This commit is contained in:
Dirk-Willem van Gulik 2020-04-12 18:07:07 +02:00
parent bacdca2752
commit 2e1e3fea78
1 changed files with 10 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
implementation-profiles/profile.md
View File

@ -45,9 +45,7 @@ Test vector:
(Aligned with https://github.com/dirkx/DP-3T-Documents/tree/editable-version/impl/design-2-openssl-C)
The depth of the Cuckoo filter shall be 4.
The hash shall be a SHA256.
The hash shall be a SHA256 (Note; given a reveal 60-90 bits - perhaps not so crucial).
The key shall be 32 bytes which are used as follows:
@ -62,10 +60,10 @@ Where verify limit is set as low as is feasible given the acceptable false posit
The Cuckoo filter shall be serialised as:
Magic string 4 bytes D3, D3, 3D, 3D
Major version 1 byte, currently 1 for this version
Minor version 1 byte, currently 0
Version 1 byte, major/minor, currently set to 0x10 for version 1.0
<Depth> 1 byte, fixed to 4
<verifylimit> 1 byte
<bits-hash> 1 byte, without the occupy bit.
<bits-verify> 1 byte
<N buckets> 4 bytes, unsigned 32 bit integer, network order
<N slots> 4 bytes, unsigned 32 bit integer, network order
@ -73,9 +71,12 @@ Followed by
<N buckets> with each
<Depth> slots with each
is occupied 1 bit
partial hash 31 bits, network order, of which <Z> are relevant.
verify hash <verifylimit> bytes of the verify hash
sequence of ( bit-hash + 1 )/ 8 rounded up bytes:
is occupied 1 bit
partial hash bits-hash bits
padding * any padding bits set to 0 if bits-hash +1 not a multiple of 8
verify hash bits-verify bits
padding * any padding bits set to 0 if bits-verify +1 not a multiple of 8
With the partial hash being limited to the number of bits needed for N buckets.