Encryption is the process of transforming plaintext using a cipher to make it unreadable to anyone except those possessing the key.

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Is AES-GCM length extension attack possible using authenticated decryption?

I am looking to encrypt a piece of data using AES-GCM with a full 16-byte GCM Tag and send it over the network using UDP. Is it safe to assume using the AEAD nature of AES-GCM that performing ...
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2answers
38 views

how to encrypt a sensitive model on android and ios

I am writing a mobile app which uses a statistical model contained in binary files. I want to be able to distribute the app freely, but I don't want anyone to be able to use my model files, even on a ...
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1answer
49 views

Storing encrypted data for offline use

A user downloads a file from a server. I want to store that file locally on the user's machine so they can view offline. For protection, it should be encrypted while not being viewed. My theory is ...
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0answers
31 views

Decrypting packets with wireshark when you have the Algorithm [on hold]

Algorithm for encryption / decryption data transmitted over the network: Code: unsigned char encryptKey[264] = { 0x2b, 0x00, 0x00, 0x00, 0xda, 0x00, 0x00, 0x00, 0x58, 0x24, 0x32, 0x6a, 0xc3, ...
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2answers
34 views

Why do I have to use multiple Keys for each direction and purpose?

I'm currently writing an examen about 'Lessons Learned in the IT-Security'. I already found some thing, which shouldn't be done. But right now I'm in trouble finding the reasons why not to do so. ...
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1answer
27 views

Emulating Client by sending encrypted hexdump to dB server and getting response back [on hold]

So I used wireshark to retrieve a hexdump that has been encrypted with RSA. I need to figure out what the response to that would be when it comes back from the server. How I imagine it would work ...
-1
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1answer
41 views

Decrypting packet data without private key [on hold]

Firstly I am not doing anything illegal. How would I go about decryption a packet from the server back to the client and vice versa and get it in plain text WITHOUT using a private key. I have tried ...
2
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1answer
73 views

Does encrypting a file make it larger?

I encrypted a Word document using Winrar by setting a password. Surprisingly the archive was larger than the original file (631 vs 614KB). I then tested to see what would happen if encryption wasn't ...
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1answer
82 views

How The Sony Hack Was Traced, and So Quickly? [on hold]

What are the steps that are required to locate a source that have routed their traffic through multiple zombie hosts, spanning multiple networks/carrier/nations?
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1answer
33 views

Windows 8.1 full disc encryption

I have a zenbook ux302 that I want to do a full disc encryption on. I had no problem using bitlocker on my stationary computer, but the zenbook doesn't seem to have that functionality? I have the ...
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0answers
19 views

How encryption/decryption of RSA private key by passphrase works?

I would like to know how exactly the encryption of private key by passphrase works. I am a software developer with no background in cryptography and I know only some basics. When I open the private ...
8
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3answers
1k views

Does the entire AES encrypted dataset have to be present to be 'cracked'?

I am implementing an AES 256 algorithm on credit cards and I am wondering if I would be strengthening or weakening the encrypted dataset if I split the dataset and persisted it in two locations. I ...
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0answers
32 views

How to securely store SSN details in a database while maintaining searches?

My question is very similar to this one, but in my situation I do not need to recover the real value. My concern with just hashing the value is that since there's a finite and (relatively) small ...
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2answers
51 views

A secure way to encrypt a connection between 2 clients securing against both passive and active adversaries

Recently I got interested in encryption and the methods behind them. So for a fun / school project I am building a program in python to encrypt data between two clients (chat and files). I'm just ...
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2answers
63 views

When do I use IPsec tunnel mode or transport mode?

I basically understand how tunnel mode and transport mode works, but I don't know when I should use one instead of another. Among the two parties who want to communicate, if one computer B doesn't ...
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0answers
28 views

KakaoTalk message encryption [closed]

I am trying to write a tool to decode the KakaoTalk chat application and the messages are encrypted with this pretty bizarre looking base64 'Lx7ZczQJ/sdOAw8DdFcauw==', That might possibly be a base64 ...
12
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0answers
874 views

Why are primes important for encryption [migrated]

Why are primes so important? Why can't we just use a random number? My guess is that it's because finding a random prime require more computing power, than finding a random number. Can anybody confirm ...
1
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0answers
28 views

Password Encoding/Encryption on ODC connection Strings

I'm interested to understand how passwords provided in ODC (Office Data Connection) connection strings are encoded or encrypted. The format of the connection string is ...
3
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1answer
45 views

Decrypting arbitrary offset of encrypted file

I want to store encrypted files on some storage backend that allows me to fetch bytes X through Y of the encrypted file. I can obviously decrypt the entire file locally and send it back to the client. ...
0
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1answer
101 views

Can you get someone's IP if you have their Skype number?

I was reading about capturing packets during skype sessions to get the other person's IP address... sounds like you can do this mainly while in a live skype chat / call between skype to skype, but Is ...
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1answer
66 views

PCI DSS - Recorded Phone Conversations

I am using the using the following image from FishNet Security as a sort of guide for the data flow diagram required by PCI DSS as defined by: 1.1.3 Current diagram that shows all cardholder ...
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0answers
19 views

how to convert mac address to floating value [migrated]

i want to change a mac address to floating point number. i tried using IEEE 754 converter online but it says "the value is out of range", how can i do it in a proper way?
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2answers
57 views

What's the best way to transform sensitive account numbers

I work on a web application that manages information about transmission setups and processes client transmission statistics to generate billing charges for the services used by these clients. The team ...
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1answer
44 views

What are the risks of encrypting a database with a single symmetric key

An application is required to store sensitive data* on each user. Additional columns are added to the database which store cyphertext encrypted on the application server. The algorithm of choice is ...
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2answers
65 views

Can a virtual machine be used instead of the host?

I was thinking of using a Debian guest as my main 'host' instead of my actual host (Ubuntu). Do you think this will have any advantages in terms of making it difficult for digital forensics to ...
2
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1answer
140 views

Reverse Engineer this basic Hash using known answer?

Little background: I forgot one of my CCTV accounts password, so used the admin account to create a new one. However I can't access the old one as it's not possible to change a user account password, ...
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2answers
136 views

Using my own encryption instead of https in app

I am writing a program that uses a webserver as a backend for communication between different users. Is it okay to use my own encryption (such as ...
2
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1answer
46 views

electronic voting system

Was looking at cryptocurrency and how, as a non techy, to get involved when I began thinking about the security of it being developed to undermine the stranglehold bankers have on economy and the ...
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1answer
30 views

Necessary components for PGP

I came across this question during an interview. I was asked: What are the two main components of PGP encryption necessary for it to work? I was thinking in line of Private and Public Keys but I am ...
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3answers
65 views

What information can be taken by submitting an online form?

Sorry I'm pretty clueless with this stuff.. I know that vpn hides your IP address when just browsing websites, but how about submitting an online form, such as when you send an inquiry? Would my IP ...
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3answers
108 views

Hardware encryption for Flash Drives

Could someone tell me the difference between Hardware encryption and Software encryption? (With regards to flash drives, if it makes any difference). From what I understand, software encryption is ...
0
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2answers
84 views

Prevent a file from being encrypted

Is it possible to prevent a file from being encrypted, or at least being easily decrypted in case of encryption? For instance; with the Crypto Locker malware attacking users, could you set up a ...
22
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6answers
3k views

What real world benefits does PGP have over sending email with SSL/TLS such as with HTTPS?

I've been learning about PGP, and I asked myself, "Why?" For example, if I'm using https://mail.google.com, then what benefit would adding PGP offer that would justify it being used? I can ...
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0answers
35 views

Suggestion of encrypt method for short fixed size result

I'm searching for a encrypt method that receives an int variable and outputs exactly 11 hexadecimal digits. I'm starting on a existing application, that already has a database of more than 130.000 ...
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1answer
72 views

How does this implementation of full disk encryption work?

I have a laptop that has Sophos Safeguard full disk encryption on it. I booted the machine into another operating system on a USB stick and attempted to read the disk from the other OS, and I verified ...
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1answer
58 views

Is digital certificate with 'issued to' field as *.example.com valid?

Came across a Digital Certificate which has issued to field *.example.com Is this a valid certificate?
2
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1answer
48 views

Long passwords and key derivation functions

Not being a security expert, I have a rather theoratical question that I have been thinking about for quite a while now: Let's imagine an encryption software that takes a user-provided password, ...
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4answers
227 views

Creating a secure and encrypted e-mail service

Model People living in countries with totalitarian, oppressive and other threatening regimes should be able to use this system and have some degree of privacy when communicating. Objectives ...
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2answers
760 views

Timing attack against HMAC in authenticated encryption?

In an answer to another question of mine, it was noted that a class using standard string comparison functions when checking the HMAC in authenticated encryption would make the class vulnerable to ...
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1answer
121 views

Protecting decryption key on server

What is the most suitable way to encrypt and decrypt sensitive data on a public cloud server disk without storing the decryption key on the server in plaintext? REQUIREMENTS In our SaaS web/mobile ...
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0answers
11 views

Decrypting a Windows MIG file [migrated]

I was wondering if anyone has any experience with decrypting an MIG file created by Windows 7 easy transfer. We have a client that has 15 years of genetic research and never wrote down her password ...
4
votes
1answer
177 views

How To Encrypt Group Emails?

I'm interested in encrypting e-mails. My very, very basic understanding is that I am to generate a private key, and share my public key with the message recipient (who will share his public key with ...
2
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2answers
66 views

Why is GPG encrypted message size not proportional to number of recipients & file size?

I have noticed that when I am using GnuPG to encrypt a file for multiple recipients, the size of the encrypted message does not seem to be directly proportional to the number of recipients. For ...
1
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0answers
37 views

FIPS Compliance with iOS app

Our company is working on getting FIPS validation for the iOS app and is in the initial phase. We have decided to use a private FIPS-certified libraries for using in the crypto modules. I have some ...
1
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1answer
90 views

“Inverted” asymmetric encryption

I am developing a system to prevent frauds in tickets. What do I need? An algorithm to generate a QR Code that will be shown to my clients in a ticket. An algorithm to validate (offline) the ...
2
votes
1answer
40 views

Protecting a statistics endpoint

When we download an application - it asks us whether it's ok to submit statistics, error reports to the vendor. Since this data is sent from the application to server endpoint - I am wondering how ...
3
votes
2answers
132 views

How can a connection be secure, if somebody observes it from the beginning? [duplicate]

If somebody observes a connention between client, and the server, then he can see the keys, by the following data encrypted is. As far as I know, if I connect to a server, then it sends me some keys, ...
7
votes
1answer
473 views

Is there a method to get plain-text from cipher-text in HMAC SHA-1, given that the key is known?

This is technically not even an attack. We have all the resources at hand, except for the original plain-text. We have the cipher-text (to be converted back to plain-text), as well as the key. The ...
0
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0answers
46 views

Older Cell / Smart phones were susceptible to bluesnarfing / bluetooth attacks, Why specifically are smartphones secure from this attack now?

Older cell / smart phones were susceptible to bluesnarfing / Bluetooth attacks, Nokia phones in particular. But now in days, modern smart phone and cell phones that use Bluetooth technology for ...
2
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3answers
134 views

Are there any flaws in this two way cryptographic function?

I created a simple two way cryptographic function which allows you to encrypt a message and decrypt it with the same key. Here's how it works. Split the message into an array of 32-bit (or something ...