Key generation is the process of generating keys for cryptography. A key is used to encrypt and decrypt whatever data is being encrypted/decrypted.

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Key hierarchy structure

If I am going to use a master key to generate a session key, the master key must be "stronger" than the session key. For instance, I should not be distributing a 128-bit AES keys with a 56-bit DES ...
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114 views

Secure Handshake and register for Auth

The registration The Start - pre-authentication Let's assume there are Alice and Bob. They know each others public keys and each of them generates a random string - Bob's Bobkey and Alice's ...
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MPPE-Send and Receive key derivation from MS-CHAPv2

I am trying to get the MS-MPPE-Send-key and MS-MPPE-Recv-key from the MS-CHAPv2 challenge material. I am able to follow the RFCs 2548 3078 and 3079 to the step of getting the GetNewKeyFromSHA() it is ...
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285 views

How does a chosen ciphertext attack work on textbook RSA?

I am very new to cryptography and I am confused with something. Here is the homework question I am having trouble with: Write a program to attack the Textbook RSA Encryption Scheme, in order to ...
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28 views

Algorithm to generate (and verify) string of 4 quad alpha numeric code

I am writing a system, for which I need to generate unique transaction numbers (which can be verified by myself). I want to use something similar to that used by credit cards, where a string of the ...
3
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33 views

Critical sub-packets in OpenPGP not used

OpenPGP in RFC4880 allow to tag signature sub packets as "critical" by setting the high bit 7 in the packet type. I checked a few keys generated with GnuPG2 and all the sub packets are not critical, ...
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37 views

Preventing a key from being found by analysis

Lets say Alice wants to send an encrypted message to Bob. They both know a secret key. Alice uses the key to encrypt the message and Bob uses the key to decrypt the message. Now, if the handshake ...
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77 views

OpenSSL key derivation

I'm trying to manually decrypt DTLS packets sent by OpenSSL. The cipher suite used between the server and the client is TLS_RSA_WITH_AES_256_CBC_SHA256 and my understanding is that the IV used by ...
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What is the best practice: separate ssh-key per host and user VS one ssh-key for all hosts?

Is it better to create a separate ssh-key for each host and user or just using the id_rsa key for all host to authenticate? Could one id_rsa be a malpractice for the privacy/anonymity policies? ...
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20 views

Should RSA primes p and q should differ in length by “a few digits”? [migrated]

When generating RSA keys in the original RSA paper it is stated: "to gain additional protection against sophisticated factoring algorithms, p and q should differ in length by a few digits" Why is ...
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Best practices: Use of a single private key as a person, or multiple to identify self across domains?

Similar to the question here, I'd like to apply the same question to a person. For example, I have implanted a chip in my hand that holds an encrypted private key that serves as my personal unique ...
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1answer
19 views

Are there any mechanisms to verify the correctness of a burned disc?

I was recently recommended a specific smartcard over on HardwareRecs.SE. As part of this, the answerer (our ursine overlord) stated that the cards in question don't offer a means to securely backup ...
2
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1answer
696 views

Determine private key size using public certificate [duplicate]

I have a public certificate in a PEM (.pem) file -----BEGIN CERTIFICATE----- MIICsjCCAZqgAwIBAgIJAMA1YIQ2JLXDMA0GCSqGSIb3DQEBBQUAMBExDzANBgNV ... 29V/R9RZOoSBHDzGPL84wm4qojMuwQ== ...
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24 views

key hierarchy management and master key

Now, I have this equation, {{K_ab}K_bs}K_as. K_ab is encrypted by K_bs then whole packet is encrypted by K_as I think the key structure is K_as is the master key, K_bs is under K_as and K_ab is the ...
2
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2answers
161 views

Which part is the longest when gerating RSA key pairs?

Whether I use openssll or gnutls's certtool, I end in a single threaded part which take several minutes. When I try to compile the libraries with auto-parallelizer advanced efficient tools. It sill ...
15
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2answers
630 views

Alternatives to HTML's deprecated <keygen> for client certs?

The keygen tag is used to make browsers generate private keys and POST the resulting CSR to the server, which can then issue a certificate. It's now been deprecated, for rather stupid reasons but ...
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1answer
31 views

How to properly use PGP for e-mail encryption/signature (key generation, key rollover, etc.) [duplicate]

To improve my privacy, I would like to use PGP to encrypt/sign my e-mails. How should I proceed to use PGP in a secure fashion? I am trying to think about how to do it properly. From what I found, ...
3
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57 views

Is it possible to use parallelism when computing a key derivation function for a single password/key?

Suppose I have an AES-256 encrypted file, and I want to derive the key using PBKDF2 and a given salt with a large number of rounds (say 1 million), but I'm limited by user tolerance for UI lag when ...
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Are OpenStack SSH keys secure? [closed]

I found two places that describe OpenStack SSH keys, but nothing seems to say whether or not they're generated on VMs. Is this configurable? I have read and heard here (How can you securely ...
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3answers
223 views

Is it safe to generate a password for a user during sign up in a web application?

I'm working on updating a web application. It currently creates a password for a user during sign up. Is asking the user to create the password themselves safer than relying on a generated password?
3
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1answer
76 views

Can I generate a random 32 bit key by using the Java hashCode and random English words?

I want to generate and communicate a 32 bit key to Bob over a phone conversation. I know he happens to have the same Java and OS installed as I have. Suppose I have a dictionary of 100,000 (English) ...
3
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3answers
857 views

Calculate time taken to break AES key

A 256 bit AES key is required to be broken using the brute force method on a 2GHz computer. How long would it take to break the key in the best case and in the worst case situations? Assume that 1000 ...
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5answers
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Generate a PGP key with more than 4096 bits?

I would like to know if generating a PGP key with a number of bits higher than 4096 is possible and if so how?
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1answer
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Decrypting packets sent from a server to a client, how to figure out the key, having both decoded packets and encoded packets

I have written a packet sniffer which succesfully intercepts all the packets sent from a server to my computer. The problem is that the packets are encrypted(of course) and i need to decrypt them. An ...
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5answers
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SSH key-type, rsa, dsa, ecdsa, are there easy answers for which to choose when?

As someone who knows little about cryptography, I wonder about the choice I make when creating ssh-keys. ssh-keygen -t type, where type is either of dsa,rsa and ecdsa. Googling can give some ...
7
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1answer
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Is a 43 character GPG (symmetric) passphrase as secure as a 256-bit key?

A 43 character securely randomly generated mixed case alphanumeric password (with 2 extra chars to give 64 possibilities per character) would constitute 258 bits of entropy (6 * 43 = 258). Since the ...
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1answer
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Is it true that key authentications are considered insecure nowaday?

Some of the comments on this post here: http://superuser.com/q/1034137/479461 are claiming this. i.e. this one says (emphasis mine) You got brute forced. This is why one does not leave a ssh ...
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What does key signing mean?

What exactly does the "key signing" mean? So for example I have a private/public GPG key so that people could send me encrypted e-mail, because they know my public key. But: what does key signing ...
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pseudo-random key generation

If you set up a pseudo-random number generator in two different locations, but with the same seed, and you assume that they are both on the same number of ticks from startup, will they output the same ...
3
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2answers
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How to counter the security risks of shared prime factors among RSA moduli employed in practice?

A. K. Lenstra et al. in an extensive examination of the RSA moduli employed in practice (http://infoscience.epfl.ch/record/174943/files/eprint.pdf, p.10) wrote that they "could not explain the ...
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How can I create a secure random key for AES?

I need to generate a lot of shared keys for an AES method which uses in various condition, my concern is how can I generate unpredictable keys? I've had some research on Cryptographically secure ...
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Why is the Key Derivation Function important?

Let's consider this openssl command : openssl enc -aes-256-cbc -pass pass:PASSWORD Why is it important to have a good Key Derivation Function? This answer to another question suggest that GnuPG is ...
3
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1answer
157 views

OBKG on smartcard with PKCS#11

I have a new smart card with an on board PKCS#11 module and operate in a Win 8 environment. Like many cards, it can generate its own key pairs for enhanced security (only the public key can leave ...
3
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1answer
362 views

Are WoSign S/MIME certificates generated on the server side and therefore unsafe to use?

WoSign has been in the media for offering free server and client certificates. Since one of my (free) S/MIME certificate from another CA is about to expire soon after one year and WoSign offers ...
2
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Safe to Encrypt ClientId (Integer value) to use as Client Key?

Asked a follow up question (see this link). Based on my understanding, I have to issue an unique ClientId and Client Secret Key to the API subscribers right after the registration phase (client lives ...
5
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1answer
103 views

Is this a safe way to verify public keys?

I want to verify a public key like this: Alice generates a public/private key pair for encryption Alice generates a public/private key pair for signing Alice signs a random 4-letter word + the ...
5
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1answer
25 views

Transparent key management for client computers

I'm tasked with adding a backup feature to our software. This backup feature should store the customer's database on external memory. One of the requirements for this feature is that the backup should ...
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Using 8192 bit keys GPG [duplicate]

I am interested in generating 8192 bit keys out of curiosity. I know that 4096 bit keys is the maximum key strength that is recommended, but I would like to know how to increase the size. I have ...
0
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1answer
84 views

OpenSSL ecparam generates same private key every time?

Currently I am trying to make my web server as secure as possible and I am testing different cipher suites on the server side, some of them using ECDHE key exchange. When generating private EC keys, ...
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1answer
26 views

One Input Two Hashes

Suppose I have some password x, and two different hash functions h1 and h2. I can then compute the hash y1 = h1(x) and y2 = h2(x). Is there any sort of vulnerability in this case? More ...
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Find private key from private certificate

I have a private certificate from my email server in order to sign emails. At Section "Your S/MIME Personal Certificate" I can view my: private certificate public certificate My public certificate ...
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2answers
87 views

How much entropy should passphrases for encrypting ssh keys have?

When one generates keys using ssh-keygen one gets prompted for a passphrase to encrypt the generated key with. How strong should such a passphrase be, entropywise, to withstand a full-blown ...
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How many bits of security is in a n-bit modulus?

In a paper that I read, "A riddle wrapped in an enigma" by N. Koblitz and A.J. Menezes, there are several statements like this one(at page 4, section 2.3): ..., the NSA updated to Suite B [40] so ...
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3answers
158 views

How to store encryption key securely?

Say I have symmetric key which I want to store securely. One way is I will store this key on file system encrypted using user password. Then user at windows startup will enter password which will be ...
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National ID analysis and generator?

A National ID in my country consists of 14 digits: CYYMMDDXXZZZZ1C1 Where: C refers to the century - 2 for those born between 1900 and 1999, 3 for those born between 2000 to 2099 YYMMDD - ...
3
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Using the password, among other values, as key data in two-factor authentication

I'm writing an implementation and a thesis about two-factor authentication, and am currently doing some research. I'm currently looking at an implementation for deterministically generating a ...
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What is the openssl equivalent of using java's KeyPairGenerator?

I have been using java's KeyPairGenerator in order to generate public/private keys within a program so that I can encrypt and decrypt files(also using java encrypt/decrypt methods). I want to be able ...
3
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1answer
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LibTomCrypt weird ECC Keys

I recently started working with the LibTomCrypt Library because it claimed to be a well documented C Library to get started with Elliptic Curve Cryptography. In my first little program I created an ...
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2answers
195 views

Why is openssl key length different from specified bytes

I realize this is rudimentary question, but I can't seem to even google diagnose it. Why is openssl key length different from specified bytes? For example when I use the command: openssl genrsa -out ...
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247 views

Do you need more then 128bit entropy

UUID use 128 bit numbers. Currently it is not feasible to randomly produce two UUIDs that are the same. Does that means 128 bits of entropy is suitable for all cryptographic operations? I would ...