Determine signature size for devnet0

[unnawut]

#8 is merged but the signature size still needs to be determined:

• https://github.com/leanEthereum/leanSpec/pull/8/files#r2297420265
• https://github.com/leanEthereum/leanSpec/pull/8/files#r2297420883

I'm now working on https://github.com/b-wagn/hypercube-hashsig-parameters to get the size

[unnawut]

3.02734375 KiB
3100 bytes

Output

+------------------+--------------+--------------+------------+------------+--------------+------------+-------------+-------------+----------+----------------------------+--------------------+----------------------+-----------------------+----------------------+
| Number of Chains | Chain Length | Domain Layer | Target Sum | Par Len FE | Tweak Len FE | Msg Len FE | Rand Len FE | Hash Len FE | Capacity | MH Elements per Invocation | MH Pos Invocations | Expected Nr of Tries |   Verifier Hashing    | Signature Size [KiB] |
+------------------+--------------+--------------+------------+------------+--------------+------------+-------------+-------------+----------+----------------------------+--------------------+----------------------+-----------------------+----------------------+
|        64        |      8       |      77      |    375     |     5      |      2       |     ?      |      7      |      8      |    9     |             15             |         1          |  23.303003119355218  | [(24, 69), (16, 73)]  |      3.02734375      |

References

Q:

I'm trying to double check that I'm generating parameters for the specs in https://github.com/leanEthereum/leanSpec/pull/9/files#diff-08804a712172c6f21080d7b0e13ffa13bc2789648a62bb41be7b31bbb1934185

So I printed more columns to compare. I'm getting the same values as most of the xmss specs PR, but I'm still missing one:

• Mapping: [XMSS Specs PR] -> [hypercube-hashsig-parameters]

• MESSAGE_LENGTH -> ?

• LOG_LIFETIME = 32 -> log_lifetime = 32

• DIMENSION = 64 -> num_chains = 64

• BASE = 8 -> chain_length = 8

• FINAL_LAYER = 77 -> domain_layer = 77

• TARGET_SUM = 375 -> exact match

• PARAMETER_LEN = 5 -> exact match

• TWEAK_LEN_FE = 2 -> exact match

• MSG_LEN_FE = 9 -> fixed value of 9 in the generator

• RAND_LEN_FE = 7 -> exact match

• HASH_LEN_FE = 8 -> exact match

• CAPACITY = 9 -> exact match

• POS_OUTPUT_LEN_PER_INV_FE = 15 -> mh_elements_per_invocation = 15

• POS_INVOCATIONS = 1 -> mh_pos_invocations = 1

The closest constant to the spec's MESSAGE_LENGTH is the generator's PERMUTATION_WIDTH_MESSAGE_HASH but it's set to 24 so I'm not sure.

Can I safely assume that hypercube-hashsig-parameters works with MESSAGE_LENGTH by default?

A:

Message length in field element is just set high enough such that you can encode 32 bytes with it, and the script (and code) asserts somewhere that this is not too large for hashing it with tweaks etc using Poseidon 24