Cryptography is the practice and study of logical means used to achieve information confidentiality, integrity and authenticity. It covers, among other things, encryption (making some data unreadable except for those who know a given secret element, called a key), data hashing (in particular for ...

learn more… | top users | synonyms

3
votes
1answer
73 views

Does PKCS #7 (CMS) add assurance to an email if a CRL/OCSP response is included, then revoked?

Suppose I issue a signing certificate in January, and have a daily CRL issued (expires in 1 day) to verify the validity of that signature. Then sometime in July I need to revoke that certificate. My ...
2
votes
1answer
65 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?
3
votes
1answer
100 views

Security of hybrid encryption scheme

I want to use a hybrid encryption scheme for file encryption. The scheme must use PKCS#1 v1.5 – which is vulerable to padding oracle attacks – because many smartcards (e.g. the OpenPGP Card) only ...
3
votes
1answer
251 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 ...
3
votes
1answer
129 views

Has the security of PuTTY been examined?

I am wondering how PuTTY stacks up against other SSH implementations with respect to scrutiny and security of its SSH2 protocol implementation. PuTTY is probably the most-used SSH client on the ...
-2
votes
1answer
59 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 ...
0
votes
1answer
65 views

What is the security/copy protection model for streaming media services?

I realize this is a broad question, but maybe there is a simple answer From my understanding, Streaming media services such as Amazon instant video, Netflix, and others do all decryption client side. ...
1
vote
1answer
58 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 ...
1
vote
2answers
60 views

Two-way encryption that can be nested?

In building a security system, I'm looking to prevent 'man-in-the-middle' attacks in a two-way encryption system, using the following setup: A sends B a message, encrypted with code 1 B sends it ...
7
votes
4answers
933 views

What happens when encrypting with private key? [duplicate]

I have a theoretical question. There is a public key-system. Person1 wants to privately send a message to person2. From my understanding, person1 is supposed to encrypt their message with public key. ...
1
vote
0answers
69 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 ...
2
votes
1answer
49 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 ...
0
votes
2answers
118 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 ...
0
votes
1answer
59 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
votes
2answers
82 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
vote
2answers
79 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 ...
2
votes
2answers
101 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 ...
3
votes
2answers
183 views

What is the point of AES key wrap (with JSON Web Encryption)?

I'm looking at JSON Web Encryption (JWE) and am left a bit confused about why you would use AES key wrapping. The document even talks about using matching key algorithm strengths: Algorithms of ...
14
votes
6answers
2k views

What are the differences between an encryption seed and salt?

Today I had a hard time explaining the difference to a friend. I know seeds are used when generating "random" strings. And salts are used when providing different outcomes to a hash. What is a ...
17
votes
1answer
468 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 ...
4
votes
3answers
22k 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 ...
12
votes
1answer
773 views

Relationship between RSA, Diffie-Hellman Key Exchange, PKI and X.509?

I am getting confused with RSA, Diffie-Hellman Key Exchange, PKI and X.509v3. I took a look of RSA's mathematics algorithm, it seems like a encryption algorithm, right? Generating public key and ...
0
votes
1answer
31 views

length of a session key in EC?

In elliptic curve cryptography what should be the length of session key? Is there a specific metric to choose one, or are they randomly generated? I was studying one paper about defence against a ...
11
votes
0answers
476 views

Strength and length of Symmetric vs Asymmetric keys [duplicate]

There are many questions surrounding the differences between symmetric and asymmetric encryption keys. I think I've read them all at this point. But I'm still left wondering: Why does a "secure" ...
-3
votes
1answer
83 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 ...
0
votes
0answers
26 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
45 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 ...
0
votes
1answer
54 views

How to save a web page with its certificate?

I've made a payment to an online store and they're claiming there's no order with the number that appeared in my screen, therefore they're refusing to send me the product. I still have the page opened ...
23
votes
5answers
5k views

Never spell a word the same way twice?

A long time ago I was reading about Renaissance-era ciphers and I remembered this quote: David Kahn, author of The Codebreakers, quotes Giovanni Battista Porta who published, in 1563, a famous ...
0
votes
1answer
82 views

SSO software – where is symmetric key stored?

In SSO software (Oracle E-SSO …), I heard about (primary) key encrypting user’s credentials, but I can’t read anything about how this key is managed ? When using smartcard, I can understand that ...
-2
votes
2answers
80 views

Will cyber security be around forever? [closed]

As time goes on, won't computers be able to automatically test for vulnerabilities to the point where they will not be prevalent any more? What I'm essentially asking is will information security be ...
1
vote
0answers
65 views

Problem in understanding Blakley's Secret Sharing Scheme

I need to implement Blakley's Secret Sharing Scheme. I have read below mentioned two research papers but still unable to understand how to implement it. 1. Safeguarding cryptographic keys 2. Two ...
0
votes
1answer
222 views

How does LSARPC protocol work?

I'm trying to understand how does the LSARPC protocol work internally. In particular, I would like to know how secured is it. I couldn't find anything in the internet or in different books.
0
votes
2answers
354 views

Generating authentication token from PHP sessions

I have a traditional PHP site which uses sessions. I've developed a real-time app in nodejs and wish to authenticate users here based on their PHP session. The procedure would go something like this: ...
0
votes
1answer
48 views

Is it possible to perform one-way OTR MITM?

Here's something that is bugging me recently: suppose that me and my friend establish an OTR session and - as a result of that - DH key exchange is performed. My friend verifies my key, but I cannot ...
0
votes
1answer
102 views

Two-factor encryption model [closed]

Please some on help me to understand this "Are you ready for this? With the two-factor encryption model your data is protected two-fold. First, a unique key is generated, encrypted, and turned into ...
3
votes
2answers
148 views

Encrypting USB traffic: Is RSA necessary for AES session key exchange when using pre-installed secret keys?

I need a solution to encrypt USB communication between device A and device B. I was thinking about configuring each device with a secret RSA-2048 key, which would be used to exchange an AES-256 ...
1
vote
1answer
74 views

Correct auth method using oAuth 2.0?

Been trying to wrap my head around oAuth 2.0, but I'm struggling figure out the correct way to implement it for our system, as there are so many different approaches. Our specifications are: Secure ...
-2
votes
1answer
84 views

Is it really worth to spend time on Telegram Crypto Contest? [closed]

Telegram is running this crypto contents. But what I heard from some people on the web is that they designed the contest in such a way that they made it practically impossible to crack. Is it really ...
7
votes
7answers
595 views

Is it possible to make a more secure random number generator algorithm by XORing two or more less secure random number algorithms?

Is it possible to make a more secure random number generator (e.g. for cryptologic purposes) by combining two or more less secure random number generator algorithms using XOR? Here is an example of ...
4
votes
1answer
116 views

Is it considered woth it to replace OpenSSH's moduli file?

Consequences of tampered /etc/ssh/moduli describes a possible risk if the moduli file for an OpenSSH server has been tampered with. Taking the logic a step further, is there any concern with the ...
2
votes
1answer
72 views

PBKDF2 strong salt for client-side hashing

What should I use as a secure/strong salt for PBKDF2 hashing when salt is not available to use before login as it will be client-side javascript to hash user+pass with PBKDF2 ? I'm going to use ...
1
vote
1answer
42 views

PBKDF2 strong salt

I want to use a strong authentication scheme, so I decided to use PBKDF2. I'm using PBKDF2 with SHA256 algorithm, 5000 iterations and I use username (which is full email address of user) as salt. So ...
0
votes
0answers
71 views

Cryptographic Testing

Given an algorithm (say, AES), how to create/generate test vectors? I have tried using the NIST test vectors for AES and found it to be working fine with a package of "chilkat". Suppose, for a ...
0
votes
1answer
106 views

Client authentication with a collection of open source distributed servers

With a collection of open source distributed servers, all sharing every users data. How can the user authenticate with any server, without the passwords being compromised by a malicious server? ...
0
votes
2answers
69 views

How do certificates work in protecting against a man-in-the-middle attack? [duplicate]

As I understand it, if Alice and Bob wants to communicate securely, they must first agree on the protocols that will be used. Then they must confirm that they are indeed communicating with each other. ...
0
votes
3answers
86 views

Constant time compares when array sizes are not equal?

What is the preferred or recommended way to pursue contestant time compares when array lengths are not equal? Should we exit as early as possible? Something like: if (array1.size() != array2.size()) ...
6
votes
3answers
225 views

Any way to prove that two devices are in the same physical space, for authentication?

I need to come up with digital proof that two physical devices are in the same (approximate) location whenever that transaction occurs. This could be: A digital ID and the authenticator A consumer ...
16
votes
3answers
5k views

Now that it is 2015, what SSL/TLS cipher suites should be used in a high security HTTPS environment?

It has become quite difficult to configure an HTTPS service that maintains "the ideal transport layer". How should an HTTPS service be configured to permit some reasonable level of compatibility while ...
2
votes
1answer
241 views

Arduino to Android secure bluetooth connection

I'm using an Arduino Uno and a nRF8001 board from Adafruit to connect to an Android phone over bluetooth. I will be using it to lock and unlock a lock and I need to make sure only verified devices are ...