#asciilifeform | 2020-11-17

asciilifeform: a 256-bit peh tape like ".1 .FF LS .1 .3 MX" will bomb on me at here.

10:01

i haven't followed exactly a linear learning schedule, so some of the earlier chapters are somewhat unfamiliar to me... but, the reason appears to be this optimization.

10:01

say, for example: if X := 2**255 and M := 2**255 - 1, X - Q would end up negative (as that tape does in my case), because of the optimization.

10:02

as a side note, a 256-bit test tape "10k_shots_256bit_ffa_slid_rnd.tape" also bombs the same way on me

~ 16 minutes ~

10:18

cgra: thanks, will look.

10:24

cgra: your example indeed bombs. the test tape doesn't, tho, interestingly (are you sure you linked the right one?)

10:24

i'll re-check

10:24

ty

10:26

sha256sum of the test tape in q is "b6388e30fb881ebd7a37bf45fb07003e0420f2c923495dfc60c0705f22cca6a2"

10:27

aa there we go.

10:27

does bomb (initially when tried i did not specify sufficient run life)

10:28

... apparently did the same in the orig. bash script which ran this tape !

10:28

hehe :)

10:29

ty for the tip-off, cgra . loox like ch14 will need same treatment as ch15 earlier.

10:29

np, glad i could provide finally some useful input

10:30

cgra: most useful external input to date, in fact.

10:31

the bomb in 15 i had to find on my own, despite certain pompous maffs phd supposedly 'read' and signed.

10:31

i dunno if i'd have spotted the issue by walking through the physical bounds proof. i stumbled upon it while experimenting

10:32

cgra: after the incident w/ 15, i've been rereading & reproving continuously ch21b/c since april !

10:32

at some pt will finally release it... apparently later rather than sooner.

10:33

!!rated cgra

10:33

deedbot

asciilifeform has not rated cgra.

10:33

!!key cgra

10:33

deedbot

Not registered.

10:33

hey cgra wouldja get in deedbot already , so i can rate you ?

10:33

asciilifeform: how much do you have currently half-complete material for ffa?

10:34

cgra: just about all of it

10:34

( 21 is done, as is 22, only hashism is entirely unwritten yet )

10:35

right

10:35

*

asciilifeform will have to unravel 14 and rewrite all of the material thereof, will prolly take a while.

10:36

i've been delaying the wot registration, because i don't have a proper understanding of best realistic approach to it yet

10:36

cgra: elaborate ?

10:38

*

asciilifeform will be back in ~40m

10:38

asciilifeform: i mean, i thought i'd learn some rsa etc first, to be able to decide what's 'good enough'. in case i have more choices avail than the current wot people had at their registration time

~ 34 minutes ~

11:12

*

asciilifeform back

11:12

cgra: atm trinque's wot system is strictly rsa, afaik.

~ 15 minutes ~

11:28

cgra: yes, use an RSA key, and there are key-length discussions in the old logs to be found.

11:28

that said, don't fester too much about doing things "right" when the foundation itself is a pile of accidental crap.

11:28

when we've moved to asciilifeform's crypter for this, much more can be said about right.

11:29

as of now deedbot sits on a gnupg.

~ 25 minutes ~

11:54

trinque: ok

12:09

wb trinque

~ 19 minutes ~

12:28

$ticker btc usd

12:28

btcinfobot

Current BTC price in USD: $17599.51

12:28

!w poll

12:28

Polling 16 nodes...

12:28

205.134.172.26:8333 : Alive: (0.082s) V=99999 (/therealbitcoin.org:0.9.99.99/) Jumpers=0x1 (TRB-Compat.) Blocks=657380

12:28

205.134.172.27:8333 : Alive: (0.080s) V=99999 (/therealbitcoin.org:0.9.99.99/) Jumpers=0x1 (TRB-Compat.) Blocks=657380 (Operator: asciilifeform)

12:28

205.134.172.6:8333 : (172-6.core.ai.net) Alive: (0.135s) V=99999 (/therealbitcoin.org:0.9.99.99/) Jumpers=0x1 (TRB-Compat.) Blocks=657380

12:28

205.134.172.28:8333 : Alive: (0.023s) V=99999 (/therealbitcoin.org:0.9.99.99/) Jumpers=0x1 (TRB-Compat.) Return Addr=0.0.0.0:8333 Blocks=657213 (Operator: whaack)

12:28

71.114.46.209:8333 : (pool-71-114-46-209.washdc.fios.verizon.net) Alive: (0.103s) V=99999 (/therealbitcoin.org:0.9.99.99/) Jumpers=0x1 (TRB-Compat.) Blocks=657380 (Operator: asciilifeform)

12:28

176.9.59.199:8333 : Could not connect! (Operator: jurov)

12:28

205.134.172.4:8333 : (172-4.core.ai.net) Alive: (0.140s) V=70001 (/therealbitcoin.org:0.7.0.1/) Jumpers=0x1 (TRB-Compat.) Blocks=657380

12:28

54.39.156.171:8333 : (ns562940.ip-54-39-156.net) Alive: (0.115s) V=99999 (/therealbitcoin.org:0.9.99.99/) Jumpers=0x1 (TRB-Compat.) Blocks=657380

12:28

185.163.46.29:8333 : Violated BTC Protocol: Bad header length!

12:28

208.94.240.42:8333 : Alive: (0.167s) V=99999 (/therealbitcoin.org:0.9.99.99/) Jumpers=0x1 (TRB-Compat.) Blocks=657380

12:28

192.151.158.26:8333 : Alive: (0.183s) V=70001 (/therealbitcoin.org:0.7.0.1/) Jumpers=0x1 (TRB-Compat.) Blocks=657380

~ 3 hours 20 minutes ~

15:49

cgra: pretty subtle mistake, btw. the proof aint wrong, per se -- Q <= X in all cases. and R in fact has at most Wm+2 bits. but in subtraction in step 5, it is necessary to add the carry to the result R, rather than bomb if carry != 0.

15:50

in cgra's example, at step 5 :

15:50

snsabot

Logged on 2020-11-17 10:01:28 cgra: asciilifeform: a 256-bit peh tape like ".1 .FF LS .1 .3 MX" will bomb on me at here.

15:50

x == 0x40000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

15:50

q == 0x3FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

15:51

x - q == 1 ; but what gets computed is X(1 .. Rl) - Q(1 .. Rl) , i.e. :

15:51

0x00000000000000000000000000000000000000000000000000000000000000000000000000000000 - 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

15:51

which yields 0, and a carry (borrow) bit 1 .

15:52

which is the actual answer, given as we know that q <= x, and did not bother running through entire subtraction (but only for the length req'd to obtain the max known bitness of R)

15:53