📅 Original date posted:2017-02-25
📝 Original message:On 02/25/2017 08:10 AM, Ethan Heilman via bitcoin-dev wrote:
>>SHA1 is insecure because the SHA1 algorithm is insecure, not because
> 160bits isn't enough.
>
> I would argue that 160-bits isn't enough for collision resistance.
> Assuming RIPEMD-160(SHA-256(msg)) has no flaws (i.e. is a random
> oracle), collisions can be generated in 2^80 queries (actually detecting
> these collisions requires some time-memory additional trade-offs). The
> Bitcoin network at the current hash rate performs roughly SHA-256 ~2^78
> queries a day or 2^80 queries every four days.
You have to not only produce a ripemd160 collision, you have to produce
a collision that is also a valid sha-256 hash - and that's much much
much more difficult.
Alice Wonder [ARCHIVE] /
npub16h…zepvl
2023-06-07 17:56:42
in reply to nevent1q…xkau
Author Public Key
npub16hal6zv9pjknpwvm2vauaq7zuhkpjahd3zgah0u50wcrwdn6z7vs9zepvlSeen on
wss://relay.noswhere.comPublished at
2023-06-07 17:56:42Event JSON
{
"id": "f25762d0b2bbd973d3dadd79454026ec6e558c99a885f59870576c2622c744af",
"pubkey": "d5fbfd09850cad30b99b533bce83c2e5ec1976ed8891dbbf947bb037367a1799",
"created_at": 1686160602,
"kind": 1,
"tags": [
[
"e",
"37053a195373ca87d2cc167b4470872a0425d55bfe62c38a20deac2033060b94",
"",
"root"
],
[
"e",
"d2dbbc77f065f5cdfc2f75446a666774a3b509de9dfd166c53691184589ef355",
"",
"reply"
],
[
"p",
"5f0a91713bf7b0eac4f3af9f2a7714d917168ae44ba350b1b95c1d4b32c3ce35"
]
],
"content": "📅 Original date posted:2017-02-25\n📝 Original message:On 02/25/2017 08:10 AM, Ethan Heilman via bitcoin-dev wrote:\n\u003e\u003eSHA1 is insecure because the SHA1 algorithm is insecure, not because\n\u003e 160bits isn't enough.\n\u003e\n\u003e I would argue that 160-bits isn't enough for collision resistance.\n\u003e Assuming RIPEMD-160(SHA-256(msg)) has no flaws (i.e. is a random\n\u003e oracle), collisions can be generated in 2^80 queries (actually detecting\n\u003e these collisions requires some time-memory additional trade-offs). The\n\u003e Bitcoin network at the current hash rate performs roughly SHA-256 ~2^78\n\u003e queries a day or 2^80 queries every four days.\n\nYou have to not only produce a ripemd160 collision, you have to produce \na collision that is also a valid sha-256 hash - and that's much much \nmuch more difficult.",
"sig": "c4d08e2f5da28daa46829fdb4462bd1e45baed7e740c99a4457c4fe94567600f925d633b885fc1d2520acab825046a384e76a96310fa2c07bd02067048d6e6a3"
}