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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4
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1answer
77 views

Do IVs need to be unpredictable?

I am encrypting a sequence of messages with AES/CTR. For each sequence, I generate a random initial IV, say IV(0). Define IV(i) = MD5(IV(i - 1)) for i = 1, ..., n. Then for each message m(i), I ...
2
votes
1answer
74 views

Is TLS enough to prevent eavesdropping? [duplicate]

Is it enough to use only SSL/TLS for client-server application with authentication, registration and data transmission (like chat)? If it is not what I also need to use?
-2
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1answer
43 views

Sanity check security scheme, is it secure? Is there cruft?

This article: Life in a post-database world: using crypto to avoid DB writes Prompted me to write this url-crypt Node.js module to convert a Secret into secure urlsafe base64 strings. Think of an ...
1
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0answers
49 views

Android 5 encryption

There's been lots of talk about the allegedly improved encryption in Android 5. Some questions about this: What is the maximum length for passphrases? (i.e. is it still limited to 16 characters?) ...
1
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0answers
36 views

authentication token not stored in DB

I am implementing a webserver and the guideline I am following suggests: - to create token by a Serializer that takes the IdUser, a symmetric key and an expiry date - provide it to the user but not ...
3
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1answer
301 views

SIM card - Cryptography

I would like to have general infos about crypto and commom SIM card in mobile phone(I know there may be different implementations, technos according to the operator...). Is crypto used only for ...
1
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0answers
27 views

How can i know my security level as “ SSL 256 bit encryption” [duplicate]

I am using openssl tool to create certificate self-signed certificate I have known that [2048 bit SSL] it is the length of the public key then what about [256 bit encryption] how can i know type of ...
2
votes
1answer
636 views

Perfectly secure Postfix MTA (SMTP) configuration

I want to secure my root server (further) service by service, starting with the SMTP service (Postfix MTA) as the most busy one. I the course of setting everything up, I read a lot about security and ...
-2
votes
1answer
70 views

Tell type of encryption if given both input and output strings [closed]

I have the string Thisisatest that is encoded as MDQ4MGFhMzRhYTNkYjM1OGIzN2NkZTJhYjZiNjUzMjY= and I am trying to find out what encryption is used here. I think that the encoded string is base64 ...
1
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2answers
57 views

Client side encryption with sustainability as a service

I only need 2 things. 1) The user to know that only him (not even then admins) can decrypt his data that rely on my server. He will always provide his key to decrypt data. 2) To be able to provide ...
1
vote
1answer
68 views

Why should I have my GPG key expire? [duplicate]

When creating a key pair using gpg it asks me for an expiration date: $ gpg --gen-key Please specify how long the key should be valid. 0 = key does not expire <n> = key expires ...
2
votes
1answer
84 views

Is it necessary to encrypt nonce in cryptographic communication?

Server and client have a pre-shared key K. Assuming that that pre-shared key is safe, so nobody other than server/client can encrypt/decrypt. Client sends a nonce N to server, server then sends back ...
1
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4answers
118 views

Which is more effective and 'secure': Compression+Encryption, or only Encryption?

This came up in an IRC discussion on freenode, and now I"m curious. The idea is that someone wants to determine whether or not encryption alone, or compression+encryption (with gpg/pgp being the ...
1
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0answers
77 views

Is it possible to trick a CA into signing a certificate by intercepting on SSL domain validation email?

From my understanding domain validation certificate are verified by receiving an email on some special email addresses on the domain (e.g. postmaster@example.com, admin@example.com) or by sending on ...
1
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0answers
73 views

Questions about SRP algorithm

I trying to use SRP algorithm but I have some questions: Is that a good choice to use for registration and authorization SRP algorithm with SSL/TLS? And for all other transmission using just ...
1
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0answers
70 views

Store 2-legged one-time password's key securely

I have a system with a OTP authentication and I need a method to encrypt the main "secret algorithm". In my system each OTP has a pair named "solution" and it is also changing like the OTP. I need to ...
1
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2answers
117 views

Encrypting short data with RSA only?

I have a case where I need to create recovery accounts and I want to create them so that nobody knows the password to them until/unless necessary. Hence, I thought that I would do it using RSA - when ...
0
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0answers
81 views

Brute-forcing a RSA private key password vs. LUKS volume

I need to store various private keys for my clients. Given these options, what would be the least prone to brute force attacks: Encrypt the private keys using a separate RSA key (each user get its ...
0
votes
1answer
43 views

How are various softwares' files/information kept safe from me, the user [closed]

I started making a simple user authentication program just for fun, and I realised I don't know how to keep safe the files that will store all the usernames and passwords. This got me thinking. What ...
1
vote
1answer
166 views

In PSK TLS, how is the key used for encryption derived?

I'm trying to decrypt a message sent over a secure communication channel using TLS_PSK_WITH_3DES_EDE_CBC_SHA. I now have the client random number, server random number, PSK identity and PSK value. My ...
2
votes
1answer
54 views

What does a FIPS validation certificate cover? Just software version or OS and hardware too?

As I understand it, if you want to be FIPS-compliant you have to use FIPS-certified components. My question is how different can your use of the component by from what's on the component's validation ...
1
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3answers
135 views

Mitigating the LUKS decryption key residing in RAM for FDE

I've come to find Full Disk Encryption to be a rather unsafe method of securing data as standardized tools are becoming available to just read out the encryption key from RAM, where the system needs ...
0
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2answers
126 views

Why use anything other than RSA for transmission encryption?

Being fairly new to the cryptography and data security space, I have sampled a few "Introduction to cryptography" sites/textbooks and they all seem to start in the same general way: This is a Caesar ...
27
votes
7answers
6k views

Can you say that since one time pad encryption is unbreakable, it is the best if used properly?

I'm currently reading about one time pad encryption, and I have a question. They say OTP encryption is unbreakable, and this can be proved mathematically. This is provided that the key used is truly ...
1
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2answers
136 views

Roommate Frequently Hacked — How Do I Protect My Network/Devices?

If you absolutely had to share a network with a user who had a very lax approach to security and was frequently hacked (1-2x month for over a year now), what might you consider doing to secure your ...
2
votes
2answers
85 views

Determine if compressed or encrypted [closed]

I have a bunch of network data and I would like to determine if it is either 1) encrypted or 2) compressed. I doubt it is both, but the potential exists. If I am assuming that the traditional ...
0
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1answer
63 views

Default Encryption - A Panacea or Placebo

I wrote this on LinkedIn - Discrete Discretion My first question is: Is it accurate to say that default encryption is a placebo? Will default decryption only make end-users think they are secure ...
2
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2answers
101 views

How can I create my own public certificate using openssl?

I have a public key/private key pair i generated using two primes p and q. I now need to use openssl to sign and create the certificate. I heard req utility and wrote this from the man pages. openssl ...
1
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2answers
102 views

What type of encoding do .pem files use to store the key?

What encoding is the modulus in RSA cryptography stored as in a .pem file? Is it something similar to base64 of the modulus? I can retrieve the modulus using the following: openssl rsa -in ...
1
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3answers
517 views

How to intercept and analyze mobile SSL application traffic?

What is the best way to analyze requests sent by a mobile application over SSL? The communication protocol is not necessarily HTTP/S so intercepting them with BURP/ZAP/Fiddler or any other HTTP proxy ...
2
votes
2answers
95 views

Hashing a password, and summing it with every byte in a file. How secure?

I have a text document with all my usernames and passwords in it sitting on my desktop. I decided to spend a couple hours making that more secure. I wrote a program for the purpose. It takes a ...
2
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2answers
124 views

RSA and AES combination in offline situation

I need to securely request and receive data from a server. The client has the RSA public key, and the server has the RSA private key. So I am generating a random key for AES-128/CBC cipher and ...
2
votes
1answer
72 views

Is the same decryption key used for data on the server as locally with Lastpass?

Lastpass stores the password databases encrypted on the server. Does it give a database to anyone who asks? If no, then what authentication (i.e. password) is used? I use Lastpass on multiple devices ...
0
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0answers
42 views

Implementation of AEAD_AES_256_GCM and AEAD_AES_128_GCM ciphers in secure RTP

I am in the process of implementing AEAD_AES_256_GCM and AEAD_AES_128_GCM ciphers in secure RTP. There is a mechanism in RFC 5116 to implement the algorithm, but I am not able to find any sample code ...
2
votes
3answers
98 views

How could a shared password database be implemented?

In the traditional form, a password database is similar to any other database file, except the contents are encrypted using a key derived from a passphrase entered by the user. The user enters their ...
19
votes
1answer
507 views

How to encrypt in PHP, properly?

How do I encrypt data in PHP, properly, using symmetric-key encryption? I have a message M and a secret S. I'm looking for a solution that uses cryptography properly without making any of the usual ...
1
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1answer
132 views

Looking for advice on storing sensitive information - Rails, Postgres, https, pg_crypto, Digital Ocean

A potential contract requires the following sensitive information to be persisted in a postgres database: Bank Account type (Uk/Int) Bank Account Number Bank Sort Code Passport Number Passport ...
5
votes
3answers
30k views

CryptoWall 3 - how to prevent and how to decrypt?

My father's computer is now infected with CryptoWall 3, according to the link below. http://www.bleepingcomputer.com/virus-removal/cryptowall-ransomware-information#CryptoWall Is there a way to ...
0
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1answer
64 views

Proprietary cards [closed]

I was recently reading about automotive fare collection systems and came across loyalty card systems. In these systems, if I understood correctly, each passenger has a card in which a value, not ...
0
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0answers
67 views

Implementation of IDEA algorithm in MATLAB

I need to implement IDEA (international-data-encryption-algorithm) in MATLAB. I have thoroughly searched in different pages and forums but couldn't find the implementation details. I also tried to ...
2
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0answers
92 views

Proper credit card encryption for use in a blacklist

I have a general encryption question. I have read through many of the encryption related questions here and I can't find any specifically addressing my concern. This is the hypothetical scenario: I ...
-3
votes
1answer
109 views

AES 256 bit key to plaintext conversion? [closed]

I'm a little rusty on cryptography, but I have successfully acquired a 256 bit key that is used for encryption and I want to know if it is possible to reverse it into its corresponding plain text ...
2
votes
2answers
133 views

Mount ecryptfs directory via SSH

I have access to a server that I use for backups. I use rsync with the --delete flag to make an exact copy of my backup directory. I have no need for incremental backups. The backup directory on the ...
0
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0answers
27 views

TLS fallback when only one protocol is enabled

Consider I have IE with ONLY TLS 1.2 enabled. TLS 1.0 and 1.1 are disabled. (And SSLv2,v3) I have a server that only supports TLS1.2, with 1.0 and 1.1 disabled as well. Assuming they share a ...
2
votes
0answers
59 views

Offering a privacy scenario with PHP mcrypt library

first of all, sorry if my question is not clear, because English is not my first language. Anyway, let-me explain the concept I'm struggling to solve as the best solution. I have some guys, and they ...
1
vote
1answer
48 views

Bus smart ticketing systems and EMV

I have recently started to study the smart ticketing systems. Most of the modern systems support the use of EMVCo standards for buying tickets in the bus. Also, in each bus usually there are more than ...
2
votes
3answers
901 views

What is Provable Security? [closed]

In computer security, what does provable security mean? I read the Provable Security article on Wikipedia, and I was able to grasp the basics. I would like to see this described in more detail, using, ...
0
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0answers
20 views

Chrome/Youtube says incorrect certificate for host? [duplicate]

Why my Youtube always ask me: Incorrect certificate for host. The server presented a certificate that doesn't match built-in expectations. These expectations are included for certain, high-security ...
1
vote
2answers
137 views

Does “Magic Numbers” weaken encryption?

I was wandering at superuser and I found this question: Compress and then encrypt, or vice-versa? Nearly all files have a Magic Number at a certain position in them. So, I wonder if I can attack (to ...
0
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2answers
85 views

Encrypt database records to be accessed by multiple users

I want to encrypt serialised customer details and store in a database to protect against attacks where the attacker has access to the raw database records. The records then need to be accessible by ...