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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How is it possible that people observing an HTTPS connection being established wouldn't know how to decrypt it?

I've often heard it said that if you're logging in to a website - a bank, GMail, whatever - via HTTPS, that the information you transmit is safe from snooping by 3rd parties. I've always been a little ...
35
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3answers
7k views

Why should one not use the same asymmetric key for encryption as they do for signing?

In an answer to a question about RSA and PGP, PulpSpy noted this: It is possible to generate an RSA key pair using GPG (for both encryption and signing -- you should not use the same key for ...
19
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2answers
8k views

where to store a key for encryption

I am looking for a way to store a key used for password encryption. I am using a mysql db which would store a user name and an encrypted password that would be encrypted using ...
21
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5answers
13k views

What ciphers should I use in my web server after I configure my SSL certificate?

There are many great questions that ask what is the best certificate to use for a website; but once the certificate is purchased, there is also the possibility to choose or edit the Cipher list. ...
15
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4answers
2k views

In what ways does Full or Partial Homomorphic Encryption benefit the cloud?

Can someone explain, in plain English, the practical ways FHE and PHE can be leveraged in the cloud? Some interesting (and confusing) links include this Microsoft Research PDF and this wiki entry. ...
93
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11answers
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Why are hash functions one way? If I know the algorithm, why can't I calculate the input from it?

Why can't a password hash be reverse engineered? I've looked into this ages ago and have read lots on it, but I can't find the explanation of why it can't be done. An example will make it easier to ...
50
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5answers
10k views

Is sending password to user email secure?

How secure is sending passwords through email to a user, since email isn't secured by HTTPS. What is the best way to secure it? Should i use encryption?
35
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6answers
8k views

How hard is it to intercept SMS (two-factor authentication)?

A lot of two-factor authentication mechanisms use SMS to deliver single-use passphrase to the user. So how secure is it? Is it hard to intercept the SMS message containing the passphrase? Do mobile ...
22
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3answers
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What steps do Gmail, Yahoo! Mail, and Hotmail take to prevent eavesdropping on email?

I would like to ask what happens when an email is sent from gmail, yahoo or hotmail public web email services? I don't understand email protocols in details, but as far as I know email traffic is ...
21
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3answers
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Is there any advantage to splitting a password?

I've been reading about the LANMAN (LM) hash and I'm curious about a particular part of the algorithm. The LM hash is computed as follows: The user’s ASCII password is converted to uppercase. ...
34
votes
8answers
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How to determine what type of encoding/encryption has been used?

I've looked on this site and on SE. but i couldn't get a handle on this. Is there a way to find what type of encryption/encoding is being used? For example, I am testing a web application which ...
11
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3answers
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Checklist on building an Offline Root & Intermediate Certificate Authority (CA)

Microsoft allows a CA to use Cryptography Next Generation (CNG) and advises of incompatibility issues for clients that do not support this suite. Here is an image of the default cryptography settings ...
41
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8answers
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Is there any technical security reason not to buy the cheapest SSL certificate you can find?

While shopping for a basic SSL cert for my blog, I found that many of the more well known Certificat Authorities have an entry-level certificate (with less stringent validation of the purchaser's ...
17
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2answers
803 views

Are URLs viewed during HTTPS transactions to one or more websites from a single IP distinguishable?

For example, say the following are HTTPS URLs to two websites by one IP over 5 mins: "A.com/1", "A.com/2", "A.com/3", "B.com/1", "B.com/2". Would monitoring of packets reveal: nothing, reveal only ...
17
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3answers
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Understanding 2048 bit SSL and 256 bit encryption

On DigiCert's page, they advertise a 2048 bit SSL with a 256 bit encryption: http://www.digicert.com/256-bit-ssl-certificates.htm What exactly is the difference here and why are two encryption bits ...
14
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4answers
1k views

Future proof encryption possible in theory?

Let's say I have a message that I want to keep safe for the next 100 years. Is it theoretically possible? Let's say the message is unique (raw picture data, raw video video data, raw text data) and ...
16
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2answers
1k views

Digital Certificate deployment: using two certs for each user?

At a large enterprise environment I have come across a deployment approach for Digital Certificates where each user is issued two (2) key pairs: One for signing documents, emails, etc. that is ...
15
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5answers
18k views

Asymmetric vs Symmetric Encryption

I am currently taking a principles of information security class. While talking about different encryption methods a large number of my classmates seem to believe that Asymmetric Encryption is better ...
19
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6answers
1k views

What are the good use cases for disk encryption?

I've been researching disk/file system encryption, and on the surface it seems like a good idea for a lot of things. But as I dig further, the security it offers seems more mirage like than real. ...
5
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1answer
960 views

What are the benefits and drawbacks of the HTML5 Keygen element?

As of January 2013, what are the potential benefits and drawbacks of the HTML5 Keygen element?
26
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2answers
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How to estimate the time needed to crack RSA encryption?

How to estimate the time needed to crack RSA encryption? I mean the time needed to crack Rsa encryption with key length of 1024, 2048, 3072, 4096, 5120, 6144, 5120, 7168, 8192, 9216, 10240, 11264, ...
18
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2answers
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symmetric encryption session keys in SSL/TLS

This question concerns the session send and receive keys used in SSL/TLS protocol. my understanding is that this key uses symmetric encryption (DES, AES, BlowFish, etc.) I'm wondering, if ...
9
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3answers
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Block chaining modes to avoid

Everyone knows that ECB operation mode with a block cipher should be avoided because of clear and obvious weaknesses. But little attention is given to comparison of the other modes in the context of ...
32
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3answers
1k views

Am I wrong to believe that passwords should never be recoverable (one way hash)?

I recently forgot my password for our cable provider online account, only to discover that they sent it to us via plain text in an email. I quickly sent an email to customer support asking them if ...
22
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4answers
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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?
11
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2answers
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What should I know before configuring Perfect Forward Secrecy?

PFS has gained attention in our audit department because of its' innate ability to limit our exposure if someone steals our private key. What pitfalls or common mistakes should I be aware of before ...
8
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1answer
564 views

Why can't I use the same key for encryption and MAC?

I wrote a simple file encryption program as an example of how to do encryption correctly, but after reading a questions about encryption + MAC, I think I made a mistake by using the same key for both. ...
4
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2answers
3k views

How expensive is it to guess a 15 character password, and should I be worried?

I'm currently using AES encryption (at home) on GNU/Linux (one of LUKS AES-256 variants with xts) and on Windows 7 (Truecrypt) with a 15 characters password (alphanumeric lowercase only plus _). ...
9
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4answers
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Why does PGP use symmetric encryption and RSA?

Looking into the details of Pretty Good Privacy, I'm confused as to the reasoning behind encrypting the message with a session key and the key with the recipient's public key via RSA. I fail to see ...
149
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7answers
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RSA vs. DSA for SSH authentication keys

When generating SSH authentication keys on a Unix/Linux system with ssh-keygen, you're given the choice of creating a RSA or DSA key pair (using -t type). What is the difference between RSA and DSA ...
75
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2answers
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What is the difference between https://google.com and https://encrypted.google.com?

Is it there any difference between the encrypted Google search (at https://encrypted.google.com) and the ordinary HTTPS Google search (at https://google.com)? In terms of security what were the ...
46
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8answers
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Online backup : how could encryption and de-duplication be compatible?

A "soon to enter beta" online backup service, Bitcasa, claims to have both de-duplication (you don't backup something already in the cloud) and client side encryption. ...
23
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5answers
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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 ...
15
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Which Instant Messaging services use or allow secure protocols, and what do those protocols cover?

We all know there's a myriad of Instant Messaging (IM) services out there. But, which of these services uses or permits protocols that actually secure your communications? For those that do, what ...
21
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4answers
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Standards for encrypting passwords in configuration files?

My workplace has a standard that plaintext passwords are not allowed in application configuration files. This makes enough sense on its face, in case someone gets access to the config files they ...
24
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5answers
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Why most people use 256 bit encryption instead of 128 bit?

Isn't 128 bit security enough for most practical applications?
8
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1answer
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When using AES and CBC, is it necessary to keep the IV secret?

If I encrypt some data with a randomly generated Key and Initialization Vector, then store all three pieces of information in the same table row; is it necessary to encrypt the IV as well as the Key? ...
13
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5answers
1k views

How should passwords be stored if they must be recoverable?

By "encrypting" passwords you are violating CWE-257: Storing Passwords in a Recoverable Format. But this is exactly what the French government wants. They want to be able to obtain the passwords of ...
12
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2answers
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Smartphone / GSM Sniffer

This question would be in the category of SmartPhone Sniffers. So we have sniffers that can show the packets that are being sent across a wired or wireless (802.11) network. I am just performing a ...
7
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3answers
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Securing an E-commerce site

I'm building a custom e-commerce site, and the user will input their credit card details on the site instead of being directed to the payment gateway's site. I'm confused as to what the critical ...
14
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4answers
900 views

Doubling up or cycling encryption algorithms

I've occasionally read the suggestion to enhance security by either doubling up on encryption algorithms (encrypt a message once with one algorithm, then encrypt the ciphertext again with a different ...
13
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3answers
765 views

How secure is aSSL (javascript)? Does it effectively mimic SSL?

Some of you may be familiar with the aSSL project, which uses AJAX/PHP to mimic the SSL protocol. It uses RSA 512 or 1024 for the keys, and AES for the actual data. It looks impressive to me in ...
13
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1answer
1k views

How would I implement “Broadcast Encryption”?

I have a stream that I want to encrypt for broadcast to 10,000 subscribers. I know I should encrypt this data using a symmetric key; and also intend that this symmetric key will be rotated every 30 ...
12
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2answers
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Encryption strategies for multi users access in production systems

I am pretty unknown to encryption strategies in production environments. So my concern is to find a solution how to strongly encrypt data, but make it available to multiple users with different keys. ...
7
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2answers
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sniffing/recording GSM 3G signals

Is it possible to sniff or record and process GSM 3G signals (from some reciever) given that there is no other signals interrupting etc (the most comfortable conditions) Update (with some supporting ...
6
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1answer
3k views

Will double encryption increase the security of cipher vs bruteforce?

Lets say, I have a function encrypt(mes,key) where : mes = message key = key Length of key is 64bits. Lets say, that only way to crack my cipher is brute force attack. If I use ...
13
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3answers
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What's the mathematical model behind the security claims of symmetric ciphers and digest algorithms?

Why can SHA-1 be considered a secure hash function? That's something I still wonder about. I understand the concepts of why modern asymmetric algorithms are deemed to be secure. They are founded on ...
10
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How might the U.K. Government's proposed internet surveillance equipment “bypass” encryption?

http://www.channel4.com/news/black-boxes-to-monitor-all-internet-and-phone-data http://rt.com/news/uk-privacy-internet-freedom-186/ 'Black boxes' will be installed by internet services providers ...
7
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4answers
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How effective is iPhone 3GS and 4 device-at-rest encryption?

My primary goal is to protect Activesync-based communication from being copied or stolen from an offline device. In that context how effective is iPhone 3GS and 4 encryption?
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How can one secure a password/key in source code [duplicate]

If there is a need for source code to have a password in it, how should this be secured? This is purely an example, but say there is an app that is using an API, and you don't want to expose ...