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Questions tagged [timestamp]

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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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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 ...
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0answers
38 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 ...
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406 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 ...
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3answers
179 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 ...
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1answer
133 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 ...
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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 ...
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3answers
198 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 ...
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2answers
343 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 ...
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695 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 ...
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1answer
142 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 ...
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1answer
384 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 ...
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1answer
95 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 ...
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43 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 ...
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2answers
733 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 ...
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1answer
57 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 ...
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2answers
341 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 ...
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2answers
205 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 ...
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110 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 ...
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1answer
446 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)...
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1answer
481 views

Do any third party time stamping signature services exist?

I'm wondering if there exists any trusted third-party service that I can submit a file, or just a signature of a file, and get back a signature of that file signed with the timestamp of when it was ...
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71 views

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 ...
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1answer
5k 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 purpose ...
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2answers
645 views

Does x509 have an “issued at” timestamp? Can you tell when an x509 certificate was issued?

The JWT Spec (RFC 7519) has an issued at field ("iat"). Does x509 have any analogous value? I see a Validity field, but nothing else time related.
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906 views

How to timestamp a document without electronic signature under eIDAS

I need to timestamp a file to prove data integrity, not authorship. I will use a RFC3161 qualified timestamping service. From the EU Regulation Section 6, Article 41, I understand that I can use a ...
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3answers
987 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....
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1answer
390 views

Adding custom embedded Precertificate SCTs into the certificate?

It it possible to insert a list of ct certificate timestamps in the my own certificate created in by internal CA using openssl configuration file. I didnt find any information about ASN.1 sequence ...
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1answer
174 views

Dual Code Signing: Should SHA-1 signature have a SHA-1 or SHA-2 timestamp?

I am signing executables for our software both with a SHA-1 and a SHA-256 signature. In addition I timestamp both of these signatures. Here I am wondering: I can timestamp the SHA-1 signature with a ...
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1answer
364 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 ...
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1answer
781 views

Issuing TSA (Time Stamping Authority) certificates

What is a practice for issuing TSA (Time Stamping Authority) certificates? I read that TSA certificates should be issued directly from Root CA, but basically TSA certificate is end entity certificate ...
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1answer
997 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 ...
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2answers
151 views

Can a time stamp protect a signature with the obsolete SHA1?

I am trying to figure out the scope of SHA1 deprecation for existent signatures. Reading this.An attacker (after 110 years) could present a fake document for a valid signature I believe this only ...
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1answer
280 views

Why AdES -A signatures require TWO timestamps?

Latest ETSI standard CAdES, XAdES and PAdES require for baseline profile LTA to fulfill previous LT, T and B levels. Summarizing,the conformance requirements are: B : Base signature with content-...
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9answers
19k views

How to prove a picture was taken before a certain date? [duplicate]

I need to prove that all my pictures were taken before a certain date. Is uploading them to Picassa, Flickr or a similar service a good way to achieve such timestamping?
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2answers
3k views

How to prove that a file was not created in advance

Sometimes we need to prove that a file was not created in advance - a good example is warrant canaries. The person releasing them may have been forced to sign the file with a future timestamp. For ...
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1answer
182 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 ...
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1answer
255 views

Is RFC 3161 necessary?

As I've been implementing RFC 3161 software components, I got to thinking about running my own TSA and how one really proves the integrity of a time stamp (preferably without violating patents). I ...
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1answer
1k views

How to prove that something happened before some time in a distributed way? [closed]

To prove that something happened after some time in a distributed way, just refer to something publicly know just before. Is that right? (Though I wonder how to make the time granularity smaller.) ...
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1answer
5k views

SHA-256 Timestamp not recognized in windows 7 when dual signed

I wanted to dual sign my exe so that the XP and Vista users can use the software. But when i dual sign the exe with SHA1 and SHA256 timestamps, In windows7 only 1 timestamp is shown. To dual sign I ...
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1answer
217 views

Why timestamping chain is better than “code signature” chain?

Timestamping is recommended as the way to prolong signature validity after its certificate expiration date. One just need to add new timestamp signature before previous timestamp is expired. But what'...
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1answer
2k views

Timestamp vs Replay attack

1) A → B : username, timestamp, h(password) 2) A → B : username, h(password), h(timestamp) Can above two formula prevent from suffering replay attack? I think 1 is immune from replay attack but i ...
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106 views

Is there a cryptographically secure way to verify the date of a process? [duplicate]

I have a few git repositories of content that will be updated constantly over the next decade. At some point down the road I anticipate being asked to prove that the content was actually in the state ...
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2answers
494 views

Could I use a TimeStamp also as IV?

For an academic application, I use AES-GCM to encrypt my frames between 2 parties. To enhance security, and reduce the possibility of replay, I'd like to use a TimeStamp in my frame exchanges. But, ...
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1answer
1k views

Can setting the date on your iPhone to the epoch really brick it? [closed]

So, I've started seeing warnings that there is a troll/hoax saying that people should set the date on their phone to 1st January 1970 to get a retro logo to display. The warnings say that this will ...
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1answer
306 views

Generation of a shared nonce that cannot be pre computed [closed]

Is there any system out there currently, which can generate a nonce, which all nodes on a distributed network can agree and calculate the same nonce at the same time, but one an attacker cannot pre ...
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1answer
356 views

Different Microsoft-signed excecutables have apparently the same signature!

On Windows 10 systems, I found two versions of bootsect.exe (a Microsoft-supplied utility that writes disk boot sector) with different hashes (SHA-1 9b7463c79460a55a36b53bee0889f894b2379ec3 for one ...
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3answers
20k 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 ...
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1answer
709 views

Verification of a timestamped PDF

I'm kinda new to the process of timestamping files to provide digital integrity. For testing purposes, i use tsa.safecreative.org for PDF files. Now i've signed a couple PDF files and if i open up ...
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5answers
209 views

How to make sure nobody has read this!

Is there any computer/server which would allow me to get "guaranteed read access history" for files? For example, suppose I made a file with my plaintext passwords and simply wanted to make sure that ...
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1answer
378 views

How can I put in relation http timestamp with country time zone of the IP?

I have a series of packets within a PCAP files, among them I'm getting packet with HTTP protocol. starting from IP address I get the timestamp in GMT format and the time zone, for example: Source IP:...
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5answers
293 views

Proving an action was done at an exact time - a posteriori

I was thinking about the way git allows to edit the timestamp on commits, and how you can rewrite (public) history that way. I then drifted from that to "can we prove someone did an action at time X ...

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