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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1answer
633 views

Reliability of scanning tools on icmp timestamp responses

A security auditor has done a vulnerability scan of our network and found that one of our server has returned an TCP timestamp response such that the scanner (Nmap) is able to guess the uptime of the ...
2
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1answer
405 views

Is a Fernet token's timestamp a security risk?

A Fernet token has the following format: Version ‖ Timestamp ‖ IV ‖ Ciphertext ‖ HMAC As the above shows, the timestamp is not part of the ciphertext, so anyone can read the time the token was made. ...
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1answer
130 views

Are there security implications to not installing the Leap Second patch on Red Hat systems? [closed]

What are Leap Seconds? A leap second is a second which is added to Coordinated Universal Time (UTC) in order to synchronize atomic clocks with astronomical time. The reason we have to add a second ...
5
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1answer
205 views

Random padding in hash functions

In this answer, it was recommended that you add random padding when hashing messages for a trusted timestamp, such as for predictions, in order to avoid dictionary and brute force attacks (at least ...
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3answers
125 views

Is it safe to include timestamps in error codes that are shown to the users?

If an error occurs, our web shop generates an error-code that is shown to the user. At the moment, it does not contain a time stamp but only the day of the month. That is non-intuitive but I assume ...
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1answer
133 views

Keeping signatures valid even after the private key has been compromised

If I understand the topic of digital signatures correctly, you sign a message via hashing+encrypting it using your private key. Then, if a private key is compromised by an attacker, she could sign ...
-3
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1answer
562 views

Authentication protocol based on hash function [closed]

Is it possible that Alice can authenticate Bob without using any secret information except her password, i.e they don't share any thing else. If so, how can I authenticate Alice and ensure the ...
10
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2answers
9k views

TLS reliance on System Time

I'm interested to know if there is any reliance on system time (as defined by Linux or windows) when initiating a secure handshake. I'm aware that TCP typically uses a random number (RFC 1323) to ...
8
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2answers
2k views

How do systems protect against a stolen code-signing certificate after the certificate expires?

Imagine this scenario: 1st December 2014 - a certificate is stolen and used to sign malware with 2014-12-01 timestamp. 15th December 2014 - the certificate is revoked. Malware will be prevented from ...
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1answer
1k views

Verification code generation and expiration

I am trying to implement an application that includes registration, In order to register to the system the user shall enter his organization ID number let's say. To verify the user identity, a ...
3
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2answers
627 views

Does NTP leak local system time?

As I understand the paper An Improved Clock-skew Measurement Technique for Revealing Hidden Services (6/23 = pdf page 3), it implies that a NTP client leaks the system's local time because of TCP ...
2
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1answer
300 views

Is code-signing with a non-ssl timestamp unsafe?

Assuming your code-signing tool is secure (e.g., does not suffer from buffer overflow exploits and the like), is there any reason to be concerned if a time-stamping service is not running over SSL? ...
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5answers
7k views

Password protect an excel file for a period of time?

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 ...
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1answer
937 views

OpenTSA and PKCS11

We are planning to implement the time-stamping service (RFC 3161) using OpenTSA and we wanted to know: Does OpenTSA support PKCS #11 (Cryptoki) to talk to HSMs? BTW: I did not find documentation or ...
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1answer
913 views

Prevent Replay attacks via timestamp while client clock is not adjusted [closed]

I'm going to send my timestamp to server and server will check if it is in a given interval. What if My mobile clock is not adjusted (say it gives 2:00 pm while now it is 2:00 am). now I lost the ...
2
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2answers
18k 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 ...
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2answers
121 views

Can I save & store a user's data in a way that proves that the information has not been altered, and that the timestamp is accurate?

There are many situations where the validity of the timestamp attached to a certain post (submission of information) might be invaluable for the post owner's legal usage. I'm not looking for a service ...
13
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6answers
9k views

What is the most credible timestamp I can create for a digital file?

Is it possible to create a timestamp that is so hard to fake, that it could be used as proof or simply strong evidence in a court of law, that something was not created after a certain point in time? ...
4
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2answers
242 views

How can I validate time-sensitive data is coming from a mobile app, and not being forged?

In our application, a user selects answers to questions. Their score is based on the time spent answering each question down to a tenth of a second. The server is responsible for calculating and ...
1
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1answer
502 views

Is long-term validity definitively corrupted upon TSA certificate revocation?

Suppose a document that was signed with a long-term signature (e.g. CAdES-A): D S T1 (D - document, S - signature, T1 - time-stamp created using a time-stamping certificate C1). If C1 appears in the ...
3
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1answer
899 views

How to handle CRLs correctly in long-term electronic signatures?

What is a recommended way of handling CRLs in long-term electronic signatures (specifically the CAdES-A)? The problem I see is in that CRLs are not protected against modification (they are plain text,...
5
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1answer
3k views

How is an Authenticode timestamp verified?

For an Authenticode signed file to be verifiable by Windows after the original signing certificate has expired (typically 1-3 years after issue), the file also needs to have a cryptographically signed ...
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1answer
717 views

Why is ICMP timestamping disabled on OS X?

It would seem like ICMP timestamping is quite a useful feature for troubleshooting networks with asymmetric paths. Replies to icmp(4) timestamp requests are generated by the kernel: On OpenBSD, the ...
4
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1answer
2k 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 ...
2
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1answer
3k views

Expiring Decryption Key

So, I'm just a programmer -- I don't know much about cryptography so bare with me and my lack of knowledge in this realm. But essentially, I'm wanting to cache data that could be potentially volatile (...
5
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1answer
844 views

Trusted Timestamping Scope and Real-World Uses

What security assurances does Trusted Timestamping based on Cryotography provide? What are the real-world uses of Trusted Timestamping?
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2answers
3k views

What are the real-time applications of long term digital signature with timestamp

I want to know the real time applications that uses digital signatures with timestamps. Specially I am interested to know the applications where we can trust an old signed document which is now ...
5
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4answers
5k views

How to sign & timestamp log or zip files?

I think I can easily sign the files however I also need a timestamp from 3rd party vendor. I want to digitally sign + stamp log files including DHCP & mail because of laws here. UPDATE: I found ...
2
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1answer
600 views

Signature and Timestamp for Long Term Document Archival Question

I have a PDF document intended for long-term (many years, maybe decades) archival which I would like to digitally sign with my personal certificate to ensure its integrity. As far as I understand, I ...
9
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3answers
848 views

On-line cryptographically signed date/time?

I’m looking for a source of on-line cryptographically signed date/time. I do not need a full timestamp service, as I am happy with the information « date/time was that », without a link to a challenge/...
9
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4answers
1k 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, ...

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