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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2answers
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ECDSA ciphers and forward secrecy question about key exchange

I have heard that with forward secrecy that the ECDSA ciphers generate different keys for "each session" because they are not dependent on the private key of the server. My question is how is "each ...
2
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1answer
153 views

Is encrypting something more than once safer than hashing more than once?

I am aware of the implications that hashing something more than once correctly will increase the security of a system, but doing it incorrectly will decrease it, as noted here and on various other ...
2
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1answer
44 views

Possibility of using CA as an attack point by governmental organizations under their pressure

I was always concerned about the model of trust behind CA stuff we use . Well, for most of us, it is OK to trust them, since they are reliable organizations with a bunch of solid experience. ...
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1answer
170 views

Security margin of a winzip, Winrar password of 64 characters against GPU cracking

what s the longterm security margin of of a winzip or Winrar file encrypted with aes-256 and a password consisting of 64 completely random characters set a-z 0-9 and other printable special ...
4
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2answers
1k views

Extract AES key by comparing plaintext and encrypted data

Is there a kind of analysis which would enable me to get AES key which was used for encrypting arbitrary data while I have both original and encrypted version of data ? The problem is that the AES ...
0
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3answers
389 views

A service that claims beyond army level encryption

I would like to understand if this service is as safe and good as it claims to be: https://unseen.is This is what they say: ... Many other services that offer encryption keep the key, but ...
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2answers
52 views

Identifying/decrypting hashed/encrypted data [closed]

This weekend I took part in an security challenge. I had great fun doing it but i found a huge gap in my knowledge that I'm really keen to fill and hope someone here can help get me pointing in the ...
5
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2answers
720 views

Are Telegram secret chats secure assuming MTProto isn't?

For those who don't know: Telegram is a partially open source Whatsapp alternative (Server is closed source) which offers secret chats and normal chats. Secret chats are encrypted with Diffie-Hellman ...
2
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1answer
77 views

Drawbacks to only using TLS 1.2 ciphers in OpenSSL

I understand you would not want to do this as it would limit compatibility for older devices and platforms. However if someone were in an all TLS1.2 environment, say a very well managed internal ...
27
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5answers
18k views

Should RSA public exponent be only in {3, 5, 17, 257 or 65537} due to security considerations?

In my project I'm using the value of public exponent of 4451h. I thought it's safe and ok until I started to use one commercial RSA encryption library. If I use this exponent with this library, it ...
0
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3answers
89 views

Why do we use such a redundant language (English) for network communication? [closed]

I have heard throughout the internet that English is incredibly redundant. So why do we turn English messages in to a cipher which is then, from my understanding more vulnerable to letter frequency ...
4
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2answers
245 views

Safety of using web based proxy?

Lets say for example I have to use a public online proxy like https://www.zend2.com to load a PHP webpage controlled by me containing sensitive data over HTTPS. How would I make sure that the proxy ...
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1answer
24 views

Choosing right way to secure access to server access via socket

I have an application running on a server, that has an exposed socket to the Internet to communicate with client that is/are application(s) on a phone. How would one go about properly securing the ...
1
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3answers
94 views

How are HSMs used in payment processing on the server?

I came to know recently that HSMs are used in credit card processing on the server side but since I don't work in that space and stumped as to why its needed. I can see it used in an ATM machine - ...
3
votes
1answer
351 views

iPhone iOS 7 Encryption at Lock Screen

Following this topic, I have a question about how the OS and apps access data while the phone is locked. Particularly in the case of iPhone 5S running iOS 7. When the device is locked, what allows ...
4
votes
1answer
93 views

Is there a secure way to create and distribute Shamir Secrets?

This Shamir Secret sharing utility consumes the secret key, and then generates N keys that must be manually distributed to each person. This is probably fine for most low-security situations, but not ...
2
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1answer
87 views

Are all TCP connection protected by IPsec?

I hope this question fits this stackexchange: From what I understand, IPSec takes care of encrypting everything above the IP layer (transport, application). Does that mean that if I open a socket ...
5
votes
2answers
964 views

How does the encryption of FPGA works?

I know that FPGAS of Altera enables you to encrypt the RTL code while you work with it, what I can't understand is why it is really encrypted since once I have the FPGA, I can take it and with flash ...
1
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1answer
215 views

Using AES as a Stream Cipher

I need to send a lot of small messages that are usually between 128 bits and 256 bits long, and each message is encrypted with a separate 128 bit AES key. Therefore, to send each message with the key ...
1
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3answers
94 views

What does the pgp public key length depend on?

What does the pgp public key length depend on? Does a long private key result in a long public key? The longer public key the better; or is it even the private key the crucial factor?
2
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6answers
2k views

How are ProtonMail keys distributed?

There is a service called ProtonMail. It encrypts email on the client side, stores encrypted message on their servers, and then the recipient decrypts it, also on the client side and the system ...
9
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2answers
4k views

Encryption decryption time

Does the encryption / decryption time of rsa algorithm vary significantly with a change in key length? For example, is there a noticeable difference in encryption/decryption time between 512 bit and ...
4
votes
1answer
190 views

How is ZixCorp able to provide email encryption without a password?

I am trying to understand how/if an email I received is being encrypted. A financial institution sent me a verifiable email (i.e. not phising) asking me to fill out a pdf form to complete a ...
0
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0answers
44 views

Payment Application Integration - Encryption or HMAC

Doing an integration with an online payment provider. Payment provider will be making a web request to my server to provide some information about the basket content. On my end there's no payment ...
1
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2answers
49 views

How to identify Encryption algorithm for data coming in field/attribute values of an xml

I have data coming in the form of XML with certain XML attributes being encrypted. I am very new to encryption/decryption. So I would like a detailed explanation on how to find the encryption ...
4
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2answers
113 views

How does an insecure RNG affect cryptography, and how do I measure the corresponding loss of security?

Suppose a given random number generator has poor entropy, and is compressible by any compression algorithm (zlib, bzip2, lzma, etc). Specifically the issues with this RNG are: Bad entropy Bad seed ...
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3answers
100 views

What's the most secure way to send information from one device to another?

I need to send sensitive information from one piece of hardware to another. I was thinking wifi, but if someone obtains the password, it wouldn't be encrypted. I don't think you can use ssl unless ...
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2answers
373 views

GSM A5/1 encryption: Key management

I'm currently studying the A5/1 algorithm used for GSM encryption. I understood how thanks to the symmetric private Key and a public counter frame one can encrypt the communication between A and B. ...
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2answers
108 views

Creating an application in which all user content is encrypted

Does any one have references or sources on how to approach developing a web application in which the content is encrypted and unreadable for the developers or company owners; I'm referring to content ...
0
votes
1answer
66 views

A folder lock/encryption program that can do this? [closed]

I am looking for a program that can lock or encrypt folder, but in case if my laptop is stolen and C drive is reformatted and reinstalled, and i have locked folders on D drive, these folders to remain ...
0
votes
1answer
125 views

SSL decryption without installing a certificate on each client

Given a proxy performing MITM SSL decryption and inspection, is it possible to install a wildcard certificate (*.domain.com) on the proxy signed by a root CA (such as VeriSign or GoDaddy) such that ...
0
votes
4answers
521 views

How could I totally secure a connection between two nodes?

I'm building an authentication server in python, and was wondering about how I could secure a connection totally between two peers totally? I cannot see how in any way a malicious user wouldn't be ...
0
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2answers
2k views

PHP encrypt and decrypt with certificate

I am trying to think of the best way to encrypt and decrypt a message between two servers. I have found a lot of examples where people simply use a secret and PHP's mcrypt... ...
0
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2answers
90 views

How to combine a key and a password in practice

Alice wants to encrypt her data. She is not comfortable with using only a password. While she prefers to use a properly random crypto key, she isn't confident she can protect the key file from theft ...
0
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0answers
74 views

What else do I need to secure my data in an encrypted non-system drive?

I have to use an almost seven years old laptop running Windows 7 ultimate and want to encrypt my hard disk to protect my private data (e.g. documents, pictures, Dropbox, etc.). I encrypted a ...
0
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0answers
35 views

Composing and Inverting Symmetric Encryption Keys

First Question: Using a symmetric encryption algorithm E on a message M, users usually send E(M) to the recipient and then the recipient will compute E^-1(E(M))=M to retrieve the message. If M is ...
2
votes
3answers
94 views

How can DH provide a known secret to two parties over an unencrypted connection without it being intercepted via MITM?

Without using Private and Public keypairs, i do not understand how Diffie-Hellman is able to generate a secret key between two parties on the internet without passing something between that could be ...
25
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4answers
4k views

How secure are my passwords in the hands of Firefox using a Master Password?

I'm relying on Firefox to remember my passwords, using a Master Password of more than 25 characters. How secure is this set-up?
1
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2answers
68 views

Is there a secret-sharing public-key-encryption-based service? [closed]

I need to share some sensitive information with someone else who can only communicate via E-mail. I don't love the idea of sharing this information freely over email in plain text, so I was ...
1
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2answers
140 views

Will an IP packet to the own IP address ever leave the computer? [duplicate]

I am working on a system that consists of several applicaitons communicating with each other. Some of these applications will run on the same server and some will run on a different one. So there is ...
0
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2answers
53 views

Is server-side access control sufficient or should I encrypt querystrings

I've got an ASP Classic system that passes around sequential ids corresponding to keys in the database. I had gotten an encryption module (chilkat, an activex control) that I was using to encrypt and ...
3
votes
2answers
160 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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2answers
140 views

Can ISP use MITM attack to “break” encrypted traffic?

Use connection of A and B as an example. Their communications were encrypted by Public Key Encryption. Before they exchange their public key, ISP MITM attacked. A got "B"'s public key (ISP generated) ...
7
votes
9answers
3k views

How can I share files with other individuals using the cloud in a secure way?

I would like to use a dropbox because it is easy and convenient. But I want to encrypt the files with the public key of the intended recipient, so he will be the only one who can access the data in ...
4
votes
2answers
2k views

openssl_digest vs hash vs hash_hmac? Difference between SALT & HMAC?

openssl_digest vs hash vs hash_hmac I want to use SHA512 for storing password. Which of the above methods are best to use? Why? What is the difference between SALT & HMAC? I just read ...
25
votes
2answers
3k views

Break the popularity contest crypto

There is a very interesting puzzle on the Programming Puzzles and Code Golf site to Rearrange pixels in an image so it can't be recognized and then get it back. I understand that this is not ...
5
votes
1answer
108 views

Is a Linux environment PCI compliant if the swap file is not encrypted and PANs are loaded into RAM?

Is a Linux environment PCI compliant if the swap partition/file is not encrypted and PANs are loaded into RAM by an application?
5
votes
2answers
788 views

Website: Pre-Shared-Key Authentication

We have this web-application with high valuable (business) data. All communication is encrypted through TLS/SSL. While I consider this a really safe protocol, it can still be compromised if someone ...
-1
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1answer
265 views

PHP/Ajax Data transmission security

I'm learning about web security mechanisms. I have developed the following system in PHP and JavaScript: assuming that I have a page named: messages.php which is a real-time chat system. first when ...
3
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1answer
169 views

What is the best way to manage gpg keys across multiple devices?

I have a desktop computer and a laptop computer both running Debian. All of the devices have encrypted hard drives. I also have a phone running Cyanogenmod/Android. What is the best way to manage ...