# Tag Info

3

The main benefit of adding randomness in RSA signature padding is that it simplifies and strengthens security arguments. At least that's claimed by PKCS#1v2, paragraph above 8.1.1 (emphasis mine) RSASSA-PSS is different from other RSA-based signature schemes in that it is probabilistic rather than deterministic, incorporating a randomly generated salt ...

2

RSA-FDH is EUF-CMA in the random oracle model, unfortunately I only found a source in German for that proof. Basically it is game hopping, until you end up with breaking the random oracle assumption. Slides about a similar approach can be found here on pages 39-51 (by Alejandro Hevia), which also addresses the topic of key reduction and key length. Under a ...

3

An attack is described in Section 4.1.6 of the SEC1 document. Regarding xagawa's answer: The attack you describe is different from that described in Section 4.5 of the Blake-Wilson--Menezes paper. Specifically, their attack: (a) does not require knowledge of the secret ephemeral key $k$, and (b) changes the reference point $P$, which is not allowed in ...

1

There is no separate "digital signature exchange." A certificate is a self-contained thing; it contains an "issuer" field (with a DN of the CA that signed it) and a "signature" field (with a signature from that CA). A server does not just send its certificate in the ServerCertificate message; it sends a whole chain of certificates, starting with theirs, then ...

2

If we signed a secret message $m$ by publishing its signature $σ$ computed as $m^d\bmod N$, at least two very bad things would happen: The message would not be so secret anymore That's because anyone knows the public key $(N,e)$, and thus from $σ$ can compute $σ^e\bmod N$, which is $m\bmod N$. This reveals a lot of information about $m$, which goes ...

0

The first google-entry brought up this paper. To answer your questions: An anonymous signature is a signature that is unforgeable in the classic sense. But without the message no informations about the signer can be extracted from the signature even if brute-force of all public keys is possible. If I'm understanding things correctly, a blind signature ...

0

Of course all the above comments are valid (rogue certificates, fake-websites, ...), but here's another story: Let's assume you to buy, let's say a house. You are lazy and want to sign the contract digitally. The person, selling you the house presents you with a valid certificate and even is so nice to sign the contract you're going to sign. Now you sign ...

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The actual data can be omitted from a SignedData encapContentInfo; see current CMS RFC which is not materially changed from earlier versions. The RFC calls this "external signature"; IME it is also called "detached signature" or "clear-sign[ing,ed]", and is widely used. For example S/MIME signed messages usually are a multipart containing the plaintext data ...

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