How much much data can be verified by an electronic signature?

DBWeinstein

11/12/22, 7:30 PM

I’m trying to get a good understanding of how data encryption and signing work. I imagine these vary a bit depending on the software being used.

In particular, I am wondering about this: how much data can be verified by an electronic signature?

1 + 2

encryption

public-key

signature

fgrieu

11/12/22, 8:00 PM

"Data encryption" and "data signature" are different things. The goal of encryption is to make some information unintelligible to attackers (on top of that, public-key encryption makes encryption possible with a public key). The goal of signature is to allow anyone holding a trusted copy of a public key to insure that some information is exactly as processed by the holder of the corresponding private key (rather than forged or modified by an adversary).

Vadym Fedyukovych

11/15/22, 6:58 AM

Any chance to edit the title? Or, we might consider water signatures this April.

Score:5

Crypto

poncho

11/12/22, 7:44 PM

So, I’m wondering how much data can be verified by an electric signature?

If you're asking about how much data that a single public key signature can handle, well, there's no realistic limit.

What every signature system (at least, every one that I've heard of) does is take the message, pass it through a hash function to generate a short hash (and then generate a signature based on the hash). Hence, nothing sees the entire message except for the hash function. Even the most restrictive hash function (e.g. SHA-256) will accept any message smaller than about $2^{61} \approx 2300$ petabytes (which is far more than anything you have to sign); other hash functions have either much larger limits or no formal limits at all.

Now, the signature software you have may impose a smaller limit (probably because it might insist on having the entire message in memory at once - software can be written without that assumption, but perhaps your code insists on it anyways); however that would be a software limitation, nothing to do with the algorithm itself.

0 + 0

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: How much much data can be verified by an electronic signature?

TH: ลายเซ็นอิเล็กทรอนิกส์สามารถตรวจสอบข้อมูลได้มากน้อยเพียงใด

RO: Câte date pot fi verificate printr-o semnătură electronică?

RU: Какой объем данных можно проверить с помощью электронной подписи?

VI: Bao nhiêu dữ liệu có thể được xác minh bằng chữ ký điện tử?

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