📅 Original date posted:2017-12-27 📝 Original message: Andy Schroder On ...

Andy Schroder [ARCHIVE] /

npub1r37…6ccq

2023-06-09 12:48:09

in reply to nevent1q…lqs3

📅 Original date posted:2017-12-27
📝 Original message:
Andy Schroder

On 12/27/2017 12:18 AM, Andy Schroder wrote:
>> Channel closing
>> costs dwarf the gains to be made from cheating, however.
>>
>>> Since millisatoshis is used, is there a maximum channel funding size?
>> Yes, the upper 32 bits must be zero, from BOLT #2:
>>
>> - for channels with `chain_hash` identifying the Bitcoin blockchain:
>> - MUST set the four most significant bytes of `amount_msat` to 0.
>>
>> This gives a maximum HTLC value of .04294967295 BTC, which, back when
>> we started, was about $10.
>
> What's the point of wasting the upper 32 bits? Seems like this is a
> waste of data?
>
> If you have the lower 32 bits of data to use, and 2^32=4,294,967,296,
> then you have 4,294,967,296 milli satoshis. 1 BTC=10^11 milli
> satoshis, so 4,294,967,296 milli satoshis/((10^11 milli
> satoshis)/1BTC) = 0.04294967296 BTC. That is off by 1 milli satoshi
> from what you say above. Why is this?
>
> Regardless of the discrepancy of 1 milli satoshi, it still seems like
> 0.04294967296 BTC is kind of a low maximum channel size for a lot of
> business applications. Why do you want to limit this when you have
> those extra 4 bytes set to zero? You think any more is too much to
> safely have in a hot wallet? You felt keeping it low will encourage
> decentralization? Something else?
>
>
> Is the max HTLC value the same as the maximum channel size?

Okay, so I may have discovered part of this answer to this question in
BOLT 2 where it says: "MUST set |funding_satoshis| to less than 2^24
satoshi". However, I still don't understand the rational of why |max
||funding_satoshis doesn't equal max |amount_msat, or where the values
of (2^24)*10^3 and 2^32 milli satoshis came from. Also, why don't you
use units of millisatoshis everywhere in the spec? Sometimes it's
satoshis and sometimes it's milli satoshis.

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{ "id": "91906eee37a51fdead57c3459b40841928067de370d8d8b94e0306cf4f374d24", "pubkey": "1c7d4637a4686939cc8b4a759caace11bb63bafb75b73b6f57d7ba81f9bd6a6c", "created_at": 1686314889, "kind": 1, "tags": [ [ "e", "ef71998004bbb3cd38277488f6dd73fdbc39d9171017c840534a470b19350343", "", "root" ], [ "e", "43881cb1b7e1dfe555d80b435f66b8a38096cf455c64e45e5d0d7f61bce067d2", "", "reply" ], [ "p", "1c7d4637a4686939cc8b4a759caace11bb63bafb75b73b6f57d7ba81f9bd6a6c" ] ], "content": "📅 Original date posted:2017-12-27\n📝 Original message:\nAndy Schroder\n\nOn 12/27/2017 12:18 AM, Andy Schroder wrote:\n\u003e\u003e Channel closing\n\u003e\u003e costs dwarf the gains to be made from cheating, however.\n\u003e\u003e\n\u003e\u003e\u003e Since millisatoshis is used, is there a maximum channel funding size?\n\u003e\u003e Yes, the upper 32 bits must be zero, from BOLT #2:\n\u003e\u003e\n\u003e\u003e - for channels with `chain_hash` identifying the Bitcoin blockchain:\n\u003e\u003e - MUST set the four most significant bytes of `amount_msat` to 0.\n\u003e\u003e\n\u003e\u003e This gives a maximum HTLC value of .04294967295 BTC, which, back when\n\u003e\u003e we started, was about $10.\n\u003e\n\u003e What's the point of wasting the upper 32 bits? Seems like this is a \n\u003e waste of data?\n\u003e\n\u003e If you have the lower 32 bits of data to use, and 2^32=4,294,967,296, \n\u003e then you have 4,294,967,296 milli satoshis. 1 BTC=10^11 milli \n\u003e satoshis, so 4,294,967,296 milli satoshis/((10^11 milli \n\u003e satoshis)/1BTC) = 0.04294967296 BTC. That is off by 1 milli satoshi \n\u003e from what you say above. Why is this?\n\u003e\n\u003e Regardless of the discrepancy of 1 milli satoshi, it still seems like \n\u003e 0.04294967296 BTC is kind of a low maximum channel size for a lot of \n\u003e business applications. Why do you want to limit this when you have \n\u003e those extra 4 bytes set to zero? You think any more is too much to \n\u003e safely have in a hot wallet? You felt keeping it low will encourage \n\u003e decentralization? Something else?\n\u003e\n\u003e\n\u003e Is the max HTLC value the same as the maximum channel size? \n\nOkay, so I may have discovered part of this answer to this question in \nBOLT 2 where it says: \"MUST set |funding_satoshis| to less than 2^24 \nsatoshi\". However, I still don't understand the rational of why |max \n||funding_satoshis doesn't equal max |amount_msat, or where the values \nof (2^24)*10^3 and 2^32 milli satoshis came from. Also, why don't you \nuse units of millisatoshis everywhere in the spec? Sometimes it's \nsatoshis and sometimes it's milli satoshis.\n\n-------------- next part --------------\nAn HTML attachment was scrubbed...\nURL: \u003chttp://lists.linuxfoundation.org/pipermail/lightning-dev/attachments/20171227/f270ce79/attachment.html\u003e", "sig": "8351c633bc47f11646ab2b9714aa784adb43846622f112424f4ade11671fa3c2e7cf96f2475de0c8cc65aacf43f31033f3413bfb219fe50a12ec096e9b55e999" }