Would that be unsafe?
In observe, no.
There are some theoretical assault eventualities which are extraordinarily unlikely (if not unattainable) to occur in observe, and I’m not conscious of any profitable assaults on customers operating mild wallets corresponding to Electrum or Ledger, as a result of it might take greater than 51% SHA-256D mining energy to manufacture a proof that may persuade a lightweight pockets of some alternate actuality – however the alternate actuality would create a hard-fork with no market worth so the attacker would lose an enormous amount of cash simply to persuade his goal.
These wallets could also be “mild” as in not operating a node however they don’t have to belief the server (the server runs a node that feeds the required information to wallets), as a result of the server produces a cryptographic proof of your TX(es) inclusion right into a blockchain with the very best work.
From the Bitcoin whitepaper (the under is copied from markdown model discovered right here):
Simplified Cost Verification
It’s potential to confirm funds with out operating a full community node. A consumer solely must make a copy of the block headers of the longest proof-of-work chain, which he can get by querying community nodes till he is satisfied he has the longest chain, and procure the Merkle department linking the transaction to the block it is timestamped in. He cannot examine the transaction for himself, however by linking it to a spot within the chain, he can see {that a} community node has accepted it, and blocks added after it additional affirm the community has accepted it.
As such, the verification is dependable so long as sincere nodes management the community, however is extra weak if the community is overpowered by an attacker. Whereas community nodes can confirm transactions for themselves, the simplified methodology may be fooled by an attacker’s fabricated transactions for so long as the attacker can proceed to overpower the community. One technique to guard towards this could be to just accept alerts from community nodes after they detect an invalid block, prompting the consumer’s software program to obtain the complete block and alerted transactions to verify the inconsistency. Companies that obtain frequent funds will most likely nonetheless wish to run their very own nodes for extra impartial safety and faster verification.
