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0
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1answer
49 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 ...
3
votes
0answers
48 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 ...
3
votes
1answer
44 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 ...
0
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5answers
156 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 ...
1
vote
1answer
20 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 ...
1
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5answers
110 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 ...
2
votes
1answer
96 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
votes
1answer
85 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 ...
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1answer
112 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
votes
1answer
151 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 ...
1
vote
0answers
199 views

Is LTV in a pdf required if it has a trusted timestamp and the Verification Authority is guaranteed to remain active? [closed]

I have successfully managed to add valid "qualified digital signatures" using a USB token to the PDFs generated by our web application through TCPDF. I am now wondering if I should try to add a ...
1
vote
3answers
81 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 ...
1
vote
1answer
78 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
votes
1answer
174 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 ...
4
votes
2answers
537 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 ...
6
votes
1answer
573 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 ...
1
vote
1answer
181 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 ...
2
votes
2answers
177 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
votes
1answer
169 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? ...
3
votes
5answers
1k 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 ...
1
vote
1answer
245 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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votes
1answer
341 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 ...
0
votes
2answers
2k 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
2answers
109 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 ...
5
votes
5answers
2k 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
votes
2answers
189 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
vote
1answer
243 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
votes
1answer
369 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 ...
5
votes
1answer
1k 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 ...
1
vote
1answer
321 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 ...
3
votes
1answer
1k 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 ...
1
vote
1answer
615 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
votes
1answer
368 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?
6
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2answers
1k 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 ...
3
votes
3answers
2k 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 ...
1
vote
1answer
360 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 ...
6
votes
3answers
474 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 ...