Questions tagged [timestamp]

For questions relating to physical or digital timestamps, usually as part of a cryptographic protocol, logging, or auditing requirement. Please use the tag [time] for questions relating to system clocks.

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Use of ESSCertIDv2 in a RFC 3161 Timestamp

A qualified trust service provider under eIDAS uses ESSCertIDv2 for their time stamp tokens, but ESSCertIDv2 was not present in the RFC 3161 specification, it was added later in RFC 5816. RFC 3161 in ...
2 votes
1 answer
1k views

What's the PROPER way to validate a signature timestamp?

the purpose of adding trusted timestamps to signatures is so that they can be considered valid long beyond the validity of the signing certificate. However, this is not so easy, since TSA's signing ...
1 vote
1 answer
376 views

ICMP timestamp - firewall configured to drop timestamp request, but vulnerability scanner can send request and get a response

We use an external scanner (Qualys) to scan our external assets. We have a firewall in front of the external assets, but it is configured to whitelist the scanner so that the external assets get ...
2 votes
1 answer
225 views

Why can an expired certificate be used to sign a JAR file?

How does a timestamp prevent use of a leaked expired certificate to sign a malignant executable? If it is supposedly fine to share or leak expired certificates then why is it safe to allow use of such ...
3 votes
5 answers
8k views

Password protect an excel file for a period of time? [closed]

I'm trying to find a way to password protect an Excel file (.xlsm) beyond the built-in password encryption options. Ideally: Enter the password File works for a week(/other period of time) After a ...
3 votes
4 answers
4k views

Is it possible to track someone by sharing a youtube link with timestamp?

Is it possible to track someone by sharing a youtube link with them with a timestamp such as &t=1s if they click on it on their end? I've recently have been told not to use timestamps because of ...
1 vote
4 answers
555 views

Proving that a file existed at a time

How do I acquire the means to prove in the future that I had possission of a file now, without relying on the integrity of a single entity? (I believe one way of doing it would be to put the file ...
19 votes
3 answers
38k views

Pros and cons of disabling TCP timestamps

So, lynis informs me that I should unset net.ipv4.tcp_timestamps. I know that's a bad thing because an attacker could figure out which updates that require restarting the machine I haven't applied, or ...
0 votes
1 answer
228 views

What does the OID value in my CSR mean?

I am applying for a new code signing certificate and I specified to the CA I need a certificate that will be time stamped such that any assembly signed during the valid date range will still execute ...
0 votes
0 answers
67 views

How Can A Timestamp Be Redone Without Invalidating the Signature?

RFC 3161 - 4.3 states that: Thus, any token signed by the TSA SHOULD be time-stamped again (if authentic copies of old CRLs are available) or notarized (if they aren't) at a later date to renew the ...
16 votes
2 answers
11k views

What is the purpose of JSON Web Token (JWS)'s issued at "iat" field?

RFC 7519 specifies an optional "iat" field, indicating when a token was issued. The RFC provides a terse commentary: This claim can be used to determine the age of the JWT. What is the ...
5 votes
0 answers
304 views

What's the merit of storing LTV (long term validation) information for RFC3161 tokens and what happens if a TSA private key would leak?

I'll formulate my question in regards to timestamped PDF, but I wonder actually about the long term validation of RFC3161 tokens in general. So, PAdES has the concept of Long Term Validation, which ...
1 vote
2 answers
190 views

How can Alice ping and authenticate Bob without any of them sharing their public keyes beforehand

Both hosts have just their public and private key pair (but they do not have the other party’s public key). Bob should be authenticated Assume that the two hosts share clocks that are synced, i.e ...
0 votes
1 answer
1k views

Best practice for encrypting data on Mifare

I am currently playing around with Mifare Classic 1k. And everything I have read about it's security is true. So it's not exactly the best thing to use to avoid cloning. But I was wondering if someone ...
2 votes
1 answer
620 views

Concatenating timestamp to data before encrypting it - is this a commonly used technique?

I have a web app that communicates with a backend server, and the users of the web app are organisations that each have a single login for the entire organisation. The app is meant to be used for ...
4 votes
2 answers
22k views

How to know when a file was deleted in a NTFS filesystem?

Is it possible to know when a file in a NTFS filesystem was deleted? For example, if you have the file in the recycle bin you have the metadata file that stores when the file was sent to the recycle ...
1 vote
1 answer
467 views

Interaction of a Code Signature and a Timestamp token from a TSA

I'm currently in the process of writing a program that: Reads a binary file (a C++ program) and creates a SHA256 hash of the data (like a checksum) Use this calculated hash and a self signed CA ...
0 votes
0 answers
331 views

Using Openssl for Package signing with timestamp

We started with openssl dgst to sign and verify packages successfully. Then we thought we should do a timestamped signatures. That's when the process is bit unclear. We used the openssl ts commands to ...
0 votes
1 answer
999 views

How hard to hack are S3 Last-Modified timestamps?

Context: There are many reasons for wanting a very trustworthy timestamp on a document, as discussed in many other questions here such as this one I wrote in 2010. E.g., in an election auditing ...
6 votes
1 answer
1k views

Mitigate Time Spoofing Attack

Say Alice receives synchronized time from Tina the timekeeper. Say Ted spoofs a GPS signal, fooling Tina about the current time. Tina sends this fake time to Alice. What can Alice do to avoid being ...
5 votes
1 answer
371 views

How to put the "trust" into trusted-timestamping

As a part of my thesis, I am about to evaluate different approaches to establish the trust in trusted-timestamping performed by a TSA (see RFC3161 - Trusted Timestamp Protocol). A trustworthy ...
5 votes
1 answer
693 views

Any Known countermeasures against clock skew fingerprinting?

I know lots of websites that do clock skew fingerprinting using tcp timestamps. I know how to disable timestamps but i want to know techniques that can be used to counter clock skew fingerprinting. I ...
0 votes
1 answer
206 views

What header & footer to use when storing RFC3161 token in PEM format

The RFC3161 (https://www.ietf.org/rfc/rfc3161.txt) specification states 3. Transports There is no mandatory transport mechanism for TSA messages in this document. The mechanisms described ...
0 votes
0 answers
185 views

eIDAS qualified timestamp on email

Every document that needs to be eIDAS compliant needs to have a qualified timestamp. If we take an email as a document, then the email, based on eIDAS regulations, needs to have an qualified timestamp ...
2 votes
3 answers
742 views

How to capture not only the mtime but also the ctime when making forensic copies of files?

Context I'm investigating a compromised Linux box where I found files with malicious code. The file system is too big to just make a copy of the whole block device and so far I'm only interested in ...
1 vote
0 answers
116 views

What are the main constraints x9.95 imposes on RFC3161

So x9.95 seems to be a trusted timestamping scheme built on top of RFC3161. I couldn‘t find a good definition though how it differes or what additional constraints it imposes. Can someone list the (...
1 vote
0 answers
97 views

Looking for an RFC5816 token that does not use default hashing algorithm

I'd like to test some code that should be compatible with both RFC5816 (https://www.ietf.org/rfc/rfc5816.txt) as well as RFC3161 tokens. The problem is that all timestamping services that I found so ...
0 votes
0 answers
89 views

Why does RFC5816 not change the version number defined in RFC3161

So, RFC5816 https://www.ietf.org/rfc/rfc5816.txt changes the specification of RFC3161 https://www.ietf.org/rfc/rfc3161.txt RFC3161 specifies the 'version' field in TSTInfo to be set to 1 Why does ...
0 votes
0 answers
229 views

OpenSSL cli: how to extract ESSCertID or ESSCertIDv2 from SignerInfo of timestamp token

If I have a Timestamp token, then the signing certificate for the token is identified via the ESSCertID (for RFC3161 tokens) or the ESSCertIDv2 (for FC5816) of the signing certificate, which is the ...
1 vote
0 answers
221 views

How to store RFC3161 token for long term validation?

My question is about how to properly store RFC3161 tokens, so that their validity can be verified for a long time (aka "long term validation") Let's say I use an RFC3161 (https://www.ietf....
5 votes
0 answers
3k views

Openssl cms verify signature with timestamp and crl

I've used OpenSSL cms to sign the data and generate a detached signature. As per my requirements, I need to timestamp the signature as well, so that if the certificate expired, verification of ...
2 votes
4 answers
2k views

How to extract TSA certificate from tst file?

I have several timestamp token files that I think should have TSA certificates embedded within them because the "Request TSA certificate" option was selected when I requested them with TimeStampClient....
0 votes
0 answers
133 views

In the time side channel, is there any way to improve the measurement time accuracy?

I want to measure the execution time of a function. The execution time of this function is only slightly different in the two cases. Is there any way I can accurately measure its time to distinguish ...
0 votes
2 answers
953 views

TSA server with OpenSSL

From OpenSSL documentation of openssl-ts command: HTTP server support is provided in the form of a separate apache module Does anybody know which module is the one? I haven't found any module to ...
2 votes
3 answers
2k views

Is it safe to assume that my computer's clock will always be synced with actual time within the second or a few seconds at the worst?

Years ago, I was running a service where the moderators were able to do various actions with massive privacy implications if the accounts or contributions were less than a short period of time. I did ...
2 votes
0 answers
160 views

Should I re-timestamp old timestamps when switching to a stronger algorithm?

One of our clients uses a trusted timestamp service to prove that certain documents existed on the day they were created (they don't need a full digital signature, just the timestamp). The server uses ...
0 votes
1 answer
298 views

Why generate dedicated issuer CA for TSU certificates?

I've observed the practice of generating dedicated issuer CAs for signing TSU (Time-Stamping Unit) certificates instead of just using another existing issuer CA, for example, one used to sign S/MIME ...
0 votes
0 answers
204 views

Is it possible to get the original UUID1 from a timestamp?

Say, for example, I generate a time based UUID with the following program. import uuid uuid = uuid.uuid1() print uuid print uuid.time I get the following: 47702997-155d-11ea-92d3-6030d48747ec ...
5 votes
1 answer
3k views

Is there any functional distributed timestamp server available? If not what about this homebrew solution?

Objective A secure Arrow of Time with unpredictable future behaviour to stop attackers or DDoS BotNets from pre-calculating proof-of-work and other gateway protections for P2P/F2F. A distributed ...
9 votes
4 answers
2k views

What good, standard digital signature / timestamp verification clients are widely or easily deployed?

I'm looking for a good way to publish data along with a digital signature (and ideally a timestamp) which is as easy as possible to verify via software run locally on public data. For example, imagine ...
3 votes
0 answers
2k views

Verify PKCS#7 (CMS) detached signature with timestamp with OpenSSL

I have a PKCS#7 (i.e., CMS) detached signature of a file that is signed by my signing certificate and then timestamp signed by a TSA that is all generated by an application we wrote. I would like to ...
1 vote
1 answer
236 views

Is it possible to verify that a signature was made prior to the content of the document it is found on?

In What to do after I signed a blank sheet of paper given to me by my manager?, a distressed individual (B) has signed a blank piece of paper and given it to an adversary (A). A has openly stated to ...
1 vote
1 answer
1k views

Signing and timestamping implementation

I am writing a software that records and stores data files. I want to digitally sign and time stamp these files so that I can assure that it's Contemporaneous and Attributable (to comply with 21 CFR ...
0 votes
1 answer
339 views

How to have both TLS and Time Stamp Signing for data?

As you know, we use TLS for multiple purposes, including integrity, confidentiality and authentication and we use TSAs (Trusted Timestamp Authorities) to have signed timestamps for our data. (Read ...
1 vote
0 answers
108 views

Is it possible that a usb drive manufactured 3 months ago can have data copied to it that shows the file last modified date before manufacturing date? [closed]

I have some data that needs to be handed to a friend. I don't want to give the original drive (drive-1), so I plan to purchase a drive (drive-copy) and copy data to it. The data copied will still show ...
0 votes
2 answers
3k views

If a file on USB drive shows a certain "date modified" time in the windows explorer, can the correct added date/time be checked for the file?

If someone copied files from a drive-1 to usb-drive-2, then it seems the directories and files get the original modified time from drive-1 in some cases and in some cases not. Can it be checked if ...
0 votes
1 answer
117 views

How can one make sure that some specific directories are fully deleted (without any record of their deletion) from a USB/flash drive?

It seems data resides in USB somewhere until it's completely overwritten. But is there a way to delete big directories 10-100GB or so without zero-filling the remaining space and only eradicating ...
1 vote
2 answers
2k views

Is it possible to verifiably timestamp a video?

I am wondering if there is a way to timestamp a video. (e.g. Security camera footage) I know that there is a way to timestamp a document with a trusted time authority, and it will certainly be ...
1 vote
0 answers
189 views

Error while Verifying OpenSSL Timestamp Response

Good morning. I'm having a weird issue while verifying a response from a TSA (TimeStamping Authority). I'm using the TimeStamping Service from the ERMIS Gateway (Hellenic Public Administration). I use ...
3 votes
1 answer
1k views

When would a Authenticode signature expire?

I'm curious about how Windows check the Authenticode signature. For example, I would sign test.exe I know that if test.exe doesn't have a TS (timestamp) signature from a TSA (Timestamp Authority)...