--- /dev/null
+
+"URI Extension Block"
+
+This block is a bencoded dictionary. All buckets hold an identical copy. The
+hash of the serialized data is kept in the URI.
+
+The download process must obtain a valid copy of this data before any
+decoding can take place. The download process must also obtain other data
+before incremental validation can be performed. Full-file validation (for
+clients who do not wish to do incremental validation) can be performed solely
+with the data from this block.
+
+At the moment, this data block contains the following keys (and an estimate
+on their sizes):
+
+ size 5
+ segment_size 7
+ num_segments 2
+ needed_shares 2
+ total_shares 3
+
+ codec_name 3
+ codec_params 5+1+2+1+3=12
+ tail_codec_params 12
+
+ share_root_hash 32 (binary) or 52 (base32-encoded) each
+ fileid
+ plaintext_root_hash
+ verifierid
+ crypttext_root_hash
+
+Some pieces are needed elsewhere (size should be visible without pulling the
+block, the Tahoe3 algorithm needs total_shares to find the right peers, all
+peer selection algorithms need needed_shares to ask a minimal set of peers).
+Some pieces are arguably redundant but are convenient to have present
+(test_encode.py makes use of num_segments).
+
+fileid/verifierid need to be renamed 'plaintext_hash' and 'crypttext_hash'
+respectively.
+
+The rule for this data block is that it should be a constant size for all
+files, regardless of file size. Therefore hash trees (which have a size that
+depends linearly upon the number of segments) are stored elsewhere in the
+bucket, with only the hash tree root stored in this data block.
+
+This block will be serialized as follows:
+
+ assert that all keys match ^[a-zA-z_\-]+$
+ sort all the keys lexicographically
+ for k in keys:
+ write("%s:" % k)
+ write(netstring(data[k]))
+
+
+Serialized size:
+
+ dense binary (but decimal) packing: 160+46=206
+ including 'key:' (185) and netstring (6*3+7*4=46) on values: 231
+ including 'key:%d\n' (185+13=198) and printable values (46+5*52=306)=504
+
+We'll go with the 231-sized block, and provide a tool to dump it as text if
+we really want one.
+++ /dev/null
-
-"URI Extension Block"
-
-This block is a bencoded dictionary. All buckets hold an identical copy. The
-hash of the serialized data is kept in the URI.
-
-The download process must obtain a valid copy of this data before any
-decoding can take place. The download process must also obtain other data
-before incremental validation can be performed. Full-file validation (for
-clients who do not wish to do incremental validation) can be performed solely
-with the data from this block.
-
-At the moment, this data block contains the following keys (and an estimate
-on their sizes):
-
- size 5
- segment_size 7
- num_segments 2
- needed_shares 2
- total_shares 3
-
- codec_name 3
- codec_params 5+1+2+1+3=12
- tail_codec_params 12
-
- share_root_hash 32 (binary) or 52 (base32-encoded) each
- fileid
- plaintext_root_hash
- verifierid
- crypttext_root_hash
-
-Some pieces are needed elsewhere (size should be visible without pulling the
-block, the Tahoe3 algorithm needs total_shares to find the right peers, all
-peer selection algorithms need needed_shares to ask a minimal set of peers).
-Some pieces are arguably redundant but are convenient to have present
-(test_encode.py makes use of num_segments).
-
-fileid/verifierid need to be renamed 'plaintext_hash' and 'crypttext_hash'
-respectively.
-
-The rule for this data block is that it should be a constant size for all
-files, regardless of file size. Therefore hash trees (which have a size that
-depends linearly upon the number of segments) are stored elsewhere in the
-bucket, with only the hash tree root stored in this data block.
-
-This block will be serialized as follows:
-
- assert that all keys match ^[a-zA-z_\-]+$
- sort all the keys lexicographically
- for k in keys:
- write("%s:" % k)
- write(netstring(data[k]))
-
-
-Serialized size:
-
- dense binary (but decimal) packing: 160+46=206
- including 'key:' (185) and netstring (6*3+7*4=46) on values: 231
- including 'key:%d\n' (185+13=198) and printable values (46+5*52=306)=504
-
-We'll go with the 231-sized block, and provide a tool to dump it as text if
-we really want one.