New answers tagged

1

Possibly, sometimes. What's exchanged in the initial handshake is not just a symmetric key, but rather a "master key" for the session from which the client and server implementations of the selected cipher suite can extract keys for various purposes. A cipher suite is split into a number of algorithms for different functionality: Key exhange Bulk ...


0

You cannot sign large data blocks using any of the commonly used asymmetric signature schemes. For signing larger data, you would have to split it in blocks and sign, but if you just do that without nonces/padding/etc, it is very insecure. If you use some high-level library for your signatures, it most likely already hashes the data you give it to sign so ...


1

This is a great question, I'm not 100% sure, but my guess is that it's a proof of age that the PGP key is newer than 2013-10-19. My reasoning is as follows: What makes blockchain mining computationally hard is fiddling with the nonce until the hash of that block has a specific number of leading zeros (16 hex zeros, or 64 binary zeros in this case). Once you ...


-1

Does this establish a minimum age of the UID? No, it does not. It establishes a minimum age of the blockhash, not the other way round. If you'd want to prove the age of a UID, you'd have to do so throughout the Bitcoin network (which I don't think is possible). Or some other benefit? Only the key's holder can definitely answer for his individual ...


4

You have got that wrong, at least the encryption. Asymmetric Encryption is done using public key of the receiver. Therefore it provides Secrecy (nobody without private key can not read the message). But it does not provide Integrity -- anyone can encrypt any message and send it to you with your public key. Wikipedia is a good friend: Digital signature ...


1

For TLS 1.2 the signature should be over the two hello nonces plus the ServerDHParams portion of the ServerKeyExchange message. See rfc5246 section 7.4.3 which shows the input to the digitally-signed construct from section 4.7. But note earlier protocol versions are different for RSA signature. Two hashes, MD5 and SHA1, are concatenated, but are NOT ...


0

First of all, block-type (BT) '00' and '01' is padding for private key operation, i.e. signing. Standards define that 'data' for signature should be hash (DER DigestInfo structure) of the data that is signed. Block-type (BT) '01' padding adds fixed padding data up to the length of the modulus: 00 | 01 | FF .. FF | data Block type (BT) '00' padding means ...


1

I don't believe this would provide any more protection then the normal double submit cookies. If an attacker can overwrite one cookie using an unsecured (https) subdomain, they could just as easily overwrite 2 cookies. The attacker in the senario would get a legitimate token and signed token value, they would embed both of those in the request, and write ...


2

A cryptographic signature can only assert trust on the data it is signing. Unless there's a way to validate the validity of the unsigned fields based on the validity of the signed fields, then no you can't trust the unsigned fields.


1

The problem with naive double submit is that if the attacker could insert an attacker controlled cookie he could also set the CSRF token to this cookie and this way defeat the CSRF protection - because token and cookie match. This can be defeated if the attacker is not able to create a CSRF token and guess the matching verification cookie. This can be ...


0

Well, in the final PKCS12 you should encrypt the private key. The pkcs12 utility allows you to specify how you want to encrypt the private key. -aes128, -aes192, -aes256 use AES to encrypt private keys before outputting. -camellia128, -camellia192, -camellia256 use Camellia to encrypt private keys before outputting. I would consider aes256 very secure ...


0

The question is really about deniable authentication. There might be more than one way for the desiderata to be satisfied in the context given. For example, Alice and Bob could follow this protocol: Alice creates an OpenPGP signing key-pair with a fake name. She sends an encrypted email to Bob with the "public" key attached and instructs him to keep ...


0

You can generate your own certificate. The certificate is then used to digitally sign data, including signing a PDF. This type of certificate is a "self-signed" certificate. Documents signed with a self-signed certificate are usually regarded with mistrust since there is no inherent trust relationship between the signer's certificate and the relying party ...


0

Checking a key is signed The short answer is that you use the command gpg --list-sig <key id>. For example, I went to the site you listed above and downloaded the qubes release 2 signing key. I then imported that key into my local gpg keyring: $ gpg --import qubes-release-2-signing-key.asc which results in the following pub rsa4096/0A40E458 ...


2

Timestamping is a special kind of signature already. TS = Sign(Hash(info | X) | time) The renewal is : TS' = Sign(Hash(TS | info) | time) Of course, you could sign the original info with the new certificate and not using this technique. But this sometimes might not be possible or practical. For example when dealing with a contract, you would want to ...


3

This is why Microsoft recommends to never remove expired code signing certs from CRLs. An alternative scenario: attacker signs their malware before cert expiry. If they can remain undiscovered past cert expiry, then the cert won't get added to the CRL even on discovery, and their malware will never get blocked. Thus the revocation status of code signing ...


5

When you authenticate to Github with your SSH key, that authentication doesn't become part of the repository in any meaningful or lasting way. It causes Github to give you access for the moment, but it doesn't prove anything to anyone who is not Github. When you GPG-sign a git tag, that tag is part of the repository, and can be pushed to other copies of ...


2

As long as Bob keeps his private key secret you can simply encrypt everything which only Bob should see with Bobs public key. This also includes the signature, i.e. when sending a mail from Alice to Bob: encrypt the mail with Bobs public key make a detached signature for this mail using Alice private key encrypt this detached signature using Bobs public ...


0

Heuristics - whether used in AV, antimalware, or on a network - work on the premise of "straying from the norm." To avoid a lengthy post, please read "Understanding Heuristics." Now to give a non technical analogy that is applicable to most (networks, AV, etc): Imagine you are a security guard at a building (AV, network appliance, etc) and you are told: red ...


0

Heuristic scanner (for a file) can look/do for various things, including: sandboxing the application and analyse the behaviour (which files are created/deleled/modified, ...) looking for hooks to functions (direct disk writing, TCP socket binding, ...) strings like filenames (read/write of system files, ...) memory residence ability decryption of the ...


2

Note, I work for DocuSign. The answers by Lie Ryan and schroeder are focused on the "pure" aspects of a signing service, which is responsible for just signing, in the narrow sense. However, signing services can offer a broader product that includes additional services. For example, my company, DocuSign, offers the "Concealed View" feature. See the Quick ...


0

Like most other users here, I don't think the signing service is at any fault here. The signing service provides a certain workflow, which is the same for any documents, whether it contains PII or not. To the signing service, the document being signed is just a blob. They have no idea whether a document contains business contracts, PII, top secret ...


3

A document signing service does not process the data contained within the document it is signing. Theoretically, the signing service is completely unaware of the content. All it does is process the metadata as a whole in order to provide service. From this perspective, the fact that a certain document contains PII is not within their control, and therefore ...


1

We are working in this domain for some time. As you've already mentioned - there's a difference between the technical signature (so the systems/databases can rely the data integrity is ensured) and legal value of data itself, where (according the legal framework) legally can sign only a 'natural' person. Each state effectively 'validates' its own citizens ...



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