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 ...

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Is there an organization that reviews/approves crypto implementations?

As I understand it, NIST approves crypto algorithms but doesn't cover specific implementations. I think I've read about IEEE approving hardware implementations of, e.g. AES, but I can't think of any ...
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3answers
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MySQL OLD_PASSWORD cryptanalysis?

The password hash used for MySQL passwords prior to version 4.1 (now called OLD_PASSWORD()) seems like a very simple ad-hoc hash, without salts or iteration counts. See e.g an implementation in ...
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4answers
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Is Schneier's “Applied Cryptography” current?

I've been recommended Bruce Schneier's 1994 book Applied Cryptography as an introduction to the use and the inner workings of cryptography. Is this book still current and a good introduction?
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4answers
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What is the solution to Schneier's Law?

Schneier's law (which should probably be called Babbage's Law). States that: Anyone, from the most clueless amateur to the best cryptographer, can create an algorithm that he himself can't ...
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5answers
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Should one sign and encrypt using the same key? The Azure Training Labs are taking this approach

I'm taking the Azure lab LoadBalancing with WCF and recognise what I have been told is bad from a security perspective, but am not sure if it applies here. Can someone look at this code and tell me ...
6
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3answers
648 views

Patent free symmetric-only key exchange protocols?

I am working with a networked embedded device with AES-128 and no public key cryptography (1KB RAM, 8KB flash). At install, the device is pre-loaded with a longterm AES-128 key known also to the ...
9
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2answers
2k views

Data Encryption and Key Management in C#

Which route to take, what are the pros and cons, which is more secure.. Generate AES key, encrypt the data with it and then encrypt the AES key with RSA, save the encrypted data and encrypted AES ...
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4answers
1k views

Is Steganography considered encryption and subject to USA export restrictions?

I have written an application for Apple's iOS which embeds messages in JPEG files using steganography (see http://en.wikipedia.org/wiki/Steganography). For the purposes of this question lets assume ...
11
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7answers
3k views

Why can an encrypted private key be brute forced?

When using SSH keys to authenticate to a server for remote access, why is it possible to devise the true key and therefore the passphrase from an encrypted private key, without checking each guess of ...
5
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2answers
175 views

Complexity of web certificate attacks

I heard a while ago about someone exploiting md5 weaknesses to create a web certificate with the same md5 that a different certificate has. They were able to create a certificate through bad issuing ...
39
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4answers
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What is the use of a client nonce?

After reading Part I of Ross Anderson's book, Security Engineering, and clarifying some topics on Wikipedia, I came across the idea of Client Nonce (cnonce). Ross never mentions it in his book and I'm ...
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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 ...
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4answers
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Looking for example of well-known app using unsalted hashes

Does anyone know of a well-known application that still uses unsalted hashes for password storage? I'm looking for an example for an upcoming lecture on Rainbow Tables, and I think it would add ...
5
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2answers
1k views

Can RSA (or any public/private key algorithm) be repeated for large amounts of data?

I'm working on a small security assignment and I was instructed to implement simple encryption/decryption of files using RSA in C#. When attempting to encrypt/decrypt large files, I was informed by ...
5
votes
2answers
957 views

Generating one-time tokens from API-key?

I have a web-site for which I'm building a Drupal module that allows the users of that Drupal site to navigate to my web-site directly from the Drupal site. I intend to distribute secret API-keys to ...
14
votes
4answers
2k views

What are the chances to generate the same ssh key?

I could generate ssh keys on the client like (without password): ssh-keygen -b 8192 -t rsa -f /home/THEUSER/.ssh/id_rsa -P '' -v and copy the generated id_rsa.pub to the server: ssh-copy-id -i ...
14
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4answers
970 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 ...
26
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3answers
2k views

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. ...
8
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1answer
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Moving from a one tier to a two tier Microsoft Certificate Authority hierachy

Right now we have a single Microsoft Enterprise Root CA which issues certificates to our VPN users for two factor authentication. We're planning to extend use of the CA to issue certificates for RDP ...
11
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1answer
2k views

Renewing Microsoft Certificate Services Root Certificate

We currently have Microsoft Enterprise Certificate Server installed on a domain member machine which issues 1 year certificates to users for authenticating to VPN. We'd like to start issuing web ...
2
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2answers
362 views

What is the correct way to assess and compare Certicom's products to the alternatives?

I'm investigating Certicom's API because they are "free" with the Blackberry implementations, and have come to realize that I have several alternatives for implementing crypto such as BouncyCastle, ...
4
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3answers
614 views

Is it possible to have authentication without state

In order to login to most websites you need a username and password which is often stored in a SQL database. You are storing per-user information that can change, this is state. Can you prove that ...
4
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3answers
379 views

Are there any serious problems with this technique for generating symmetric keys?

I'm using a technique borrowed out of a book by Bruce Schneier and Niels Ferguson called Practical Cryptography. Basically, it boils down to this: Bob does this: pubk_A = Alice's public key ...
6
votes
1answer
160 views

Wireless auto-join on laptops

Maybe I have the wrong idea but this is a question that has been floating in my head for some time. Whenever you use an iPhone (or a Mac, Apple products seem to be more prone to this because it ...
6
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2answers
2k views

With reference to using Gpg4win, which is better: OpenPGP or S/MIME?

Which is better -- OpenPGP or S/MIME for higher security?
4
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2answers
220 views

What is the correct crypto to use for a “Password Wallet”, where decryption of the secret is needed?

I would like to create a shared "password wallet" where I encrypt several instances of a username/password and store it in a common location. I don't expect all key/value pairs to have the same ...
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 ...
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1answer
131 views

Enterprise and Open Cryptographic Systems/Applications?

Please can someone tell me the main Enterprise/Open Cryptographic Systems in use, I am having a hard time googling for them. I know OpenPGP is one, but is that the best and most ubiquitous one for ...
17
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2answers
790 views

Encryption and the “security time decay” of prior encrypted data

This question is on the assumption that any data once encrypted, may (eventually) be decrypted through Brute force (compute power/time) Exploits in the cryptography used Theft of private keys ...
13
votes
2answers
1k views

Evaluating the entropy gathering in a PRNG

I'm reviewing the random number generator (expected to be of cryptographic quality) on an embedded device. My point of view here is the operating system and crypto library implementer. I'm ...
13
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9answers
730 views

Anybody have additional information on the EMC RSA SecurID compromise?

The Security Advisory Press Release here doesn't have much information, the email that alerted me to this didn't help much more, and unfortunately I heard about the two Thursday evening conference ...
5
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6answers
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Should the bit-strength selection of a child certificate be influenced by the CA or the chain?

All things being equal; suppose I have a CA chain that has 1024 bits of RSA encryption. Does this mean that my selection of a child CA or WebServer certificate gains no benefit from a higher level of ...
8
votes
3answers
6k views

What SSL key should I make for IIS: RSA or DH? What bit length is appropriate?

I'm creating an SSL cert for my IIS server and need to know when I should choose the Microsoft RSA SChannel Cryptographic Provider or the Microsoft DH SChannel Cryptographic Provider. Question 1 Why ...
3
votes
4answers
456 views

Generating OpenPGP key pair with restrictions

I intend to generate an OpenPGP RSA key pair where a part (~half) of the private key is as I specify, i.e. a specific string. Are there tools for generating a key pair with such restrictions, or will ...
8
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3answers
2k views

Certificate authorities for a PKI

Some people think the certificate authorities for a PKI should be the government, but others think certificate authorities should be private entities, such as banks, corporations, or schools. What are ...
12
votes
4answers
872 views

Key management in cloud datacenters

In terms of infrastructure, how do Cloud providers (organizations providing SaaS, PaaS, or IaaS via the cloud) manage keys and cryptography? From my understanding, "private" datacenters tend to ...
6
votes
3answers
951 views

Is there a way to accept signed requests without storing client's password in plaintext?

We are developing REST Web service. We will give Identifier and Secret string to each of our REST clients. When doing requests, clients will authenticate themselves using HMAC algorithm (they will ...
11
votes
5answers
15k views

Compute the AES-encryption key given the plaintext and its ciphertext?

I'm tasked with creating database tables in Oracle which contain encrypted strings (i.e., the columns are RAW). The strings are encrypted by the application (using AES, 128-bit key) and stored in ...
9
votes
4answers
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License key / Serial number generator and checker

I need a serial number generator and accompanying checker. I would like to be able to set a salt (and maybe a length). The generator should only produce serial numbers that pass the test of the ...
12
votes
2answers
578 views

Is a large number of RSA-encrypted files a vulnerability?

Would having a large number (10^4) of RSA encrypted files make it easier for an attacker to find my private RSA key? Update: These files would be available to the attacker, and perhaps the content of ...
9
votes
1answer
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TLS replay attack - requirements of the serverHello nonce

As you all know, the SSL/TLS protocol requires both client and server to exchange (in clear text) a random number or nonce. This is presumably used to prevent replay attacks. It is not clear to me ...
28
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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 ...
12
votes
2answers
23k views

What are the differences between MD5, SHA and RSA?

MD5 tools output hexadecimal values. In the same manner, do SHA and RSA together produce a hexadecimal (or any other) output? What are the differences between the MD5, SHA and RSA algorithms?
3
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2answers
318 views

MD5 display format

When I run MD5 algorithm I am getting an output in numeric and a few lower case letters. Obviously it uses all numeric digits and rarely i saw some lower case alphabet letter. I need to understand ...
9
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3answers
1k views

How can I mitigate the threat that DPAPick poses to my DPAPI protected data?

The Windows Data Protection API (DPAPI) is the suggested method for storing secrets on Windows systems (such as database passwords required by ASP.Net applications). DPAPick was presented at BlackHat ...
9
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3answers
2k views

Suitable cipher for SMS encryption

I would like to create application for encrypting SMS messages. After long enough discussions I decided to use symmetric encryption, since handling public/private keys issue is too difficult for most ...
10
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5answers
2k views

Do mobile OS's provide crypto-quality randomness?

Which mobile OS's provide a primitive to generate crypto-quality randomness that applications can use? On desktop systems, these features are pervasive. Unix provides /dev/urandom. Windows provides ...
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5answers
390 views

What can one do when encryption methods fail?

I'm in search of an expert to answer my curiosity. Suppose that methods like AES/DES, SSH, PGP, RSA, etc. can be cracked or fail somehow. In other words, suppose that it's possible to determine one ...
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6answers
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Is PBKDF2-based System.Cryptology.RFC2898DeriveBytes() “better” for Unicode Password hashing than traditional methods?

When is it appropriate to use RFC2898DeriveBytes versus a typical hash? Update I now understand that a KDF is typically used to create a symmetric key for possible use in encrypting a stream. I ...
3
votes
1answer
221 views

What is encryption method for the 3rd part of the Kryptos text?

http://fr.wikipedia.org/wiki/Kryptos_%28sculpture%29 http://en.wikipedia.org/wiki/Kryptos I read the Kryptos wikipedia page, is says it's crypted with a "modular transposition of lines and columns". ...