I have a question regarding the security of HTLCs in a LN-channel. In a LN-transaction with multiple HTLCs (routings) to the destination one is using the signature of each node provider so that the first one who knows the secret "R" is not able to spend the other HTLCs in the channel.
That means for redemption of an HTLC the following criteria have to be presented:
- Secret "R"
If I am participating in two LN-channels. Is it then necessary out of security reasons to use two private keys so that my signature for the two HTLCs are not identical?
|LN-channel 1||LN-channel 2|
|1. Alice||1. Dina|
|2. Bob||2. Bob|
|3. Chan||3. Chan|
|4. Eve||4. Tom|
Let's suppose Bob uses for both channels the same private key.
- Chan receives the secret "R1" from Eve (channel 1) and "R2" from Tom (channel 2) after providing the respective funds to them.
- Now Chan can provide the secret "R2" to Bob, who uses his signature to unlock the HTLC to Dina.
- If Bob has used to same private key for both HTLCs, couldn't Chan now copy and paste the signature from Bob from channel 2 and use the known secret "R1" to unlock the HTLC between Bob and Alice?
Can someone verify or help me to correctly understand it? Thank you very much in advance.