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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Requirements Placed on a User of a FIPS 140-2 Validated System

Per customer requirements, I am working with a FIPS 140-2 validated network switch that is actually running in FIPS mode. This guarantees that any cryptographic operations the device performs will be ...
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0answers
52 views

How do overlay network nodes communicate without IP addresses? [migrated]

I've been reading about how Tor and I2P use cryptographic addresses to send messages to other nodes, but how does this work? I looked through the documentation for each and neither is very clear on ...
1
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0answers
26 views

Understanding Key Serial Numbers (KSN) in Derived Unique Key Per Transaction (DUKPT)

I have a number of questions regarding Key Serial Numbers (KSNs) in DUKPT: KSNs are 8 - 10 bytes long. Older implementation are 8 bytes whereas newer ones are 10 bytes. Do I risk being incompatible ...
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0answers
11 views

Blinding to mask private key operations

Blinding is often used to mask private key operations when the underlying problem is integer factorization. For example, its used in both RSA and Rabin-Williams signature schemes. This presumes ...
2
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2answers
214 views

Why is there a “des-ede3-cbc” in my rsa private key?

I have created an OpenSSL RSA private key and certificate request with 4096 bit with the following command: openssl req -newkey 4096 When I view the private key with openssl asn1parse -in privkey ...
4
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2answers
164 views

How do cryptographic algorithms help hackers to bypass Antivirus software?

I was wondering how do hackers use cryptography for bypassing antivirus software. I don't have some deep understanding on how antivirus software works, but I know that every antivirus has base of ...
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2answers
117 views

Encryption Laws in India

Is cryptography legal in India? If yes, then what type of encryption is not allowed?
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1answer
36 views

Does WebCrypto also mandate the crypto algorithms be implemented in Javascript?

I am trying to understand what WebCrypto means. From what I understand it is - A Javascript Crypto API spec that all browsers must (hopefully) support. Am I correct? If so are the crypto algorithms ...
0
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1answer
27 views

Getting multiple key matches on plaintext/ciphertext pairs in double DES

I'm trying to implement a Meet-in-the-Middle attack and just to test it out I've done some hardcoding of values, which is simply this block of simple code: byte[] key1 = new byte[] { 0x20, 0x00, ...
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0answers
20 views

2DES vs. two-key triple encryption, with no decryption step [migrated]

So studying double encryption (double DES) and understanding why it is subject to a Meet-in-the-middle attack, I tried to see if the same attack could be applied to a triple encryption with only two ...
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1answer
33 views

CryptoAPI to CommonCrypto with RC4

I have cryptographic code used in the Windows platform, which uses the Crypto API functions and need to convert this to using Common Crypto on OS X. Essentially the original code is this, with error ...
0
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0answers
41 views

Is there an encryption scheme that allows an auditor to view some, not all data?

I want to create an online chat room allows for privacy, freedom of speech, and for law enforcement to protect citizens from violent behavior. I think the best approach is to use Shamir secret ...
2
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0answers
36 views

Using RSA-SHA as/instead HMAC in OpenVPN?

While reading the manual of OpenVPN 2.3, I came across the --auth alg option. The manual says: Authenticate packets with HMAC using message digest algorithm alg. (The default is SHA1 ). HMAC is a ...
1
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1answer
47 views

Can TPM Storage Keys be Created Outside TPM?

I am interested in 'adding' preexisting keys to a TPM's storage hierarchy. An example of a desired key hierarchy can be shown as: (SRK)----->(User Storage Key)-------> User Working Key 1 ...
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0answers
82 views

Would it take long to brute force a md5 hash like this?

1be8917510-36.51929856278002 10bce1af27-99.18403192423284 103fa11cc6-87.21158325206488 Few examples above and as you can see the pattern is: 1xxxxxxxxx-{a percentage (0-100) to 14 decimal places} ...
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0answers
10 views

Checklist for Data Communication Review in ERP Solution

I am looking out for a checklist for data communication review within ERP application. I understand some of the checks would be related to digital signature, TLS/SSL use, Key Life Cycle management ...
64
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5answers
7k views

Why can't I MitM a Diffie-Hellman key exchange?

After reading the selected answer of "Diffie-Hellman Key Exchange" in plain English 5 times I can't, for the life of me, understand how it protects me from a MitM attack. Given the ...
0
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1answer
37 views

How to encrypt or store data so that only a pool of processes can share it on Windows?

I am writing an application T1 which is using SQLite database to store some sensitive data and i am trying to encrypt it securely. The issue i am facing is that i don't want my symmetric key to be ...
0
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1answer
22 views

Size of initialisation vector and plaintext in CBC mode

If I have a 16-number sequence (7,7,7,....7), and I need to encrypt this using a simple 4-bit substitution cipher, do I have to "chop" the plaintext in blocks which are of same size as the IV? In my ...
5
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4answers
251 views

Which strategy to encrypt data accessed by multiple users?

I need suggestions to design my database architecture (in the context of a web application) on the particular point of its encryption ; knowing that the following elements must be respected: 1- Data ...
7
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3answers
1k views

Why do we have such big keys?

In Chapter 7 of Applied Cryptography, Bruce Schneier claims that, due to thermodynamic limitations, "brute-force attacks against 256-bit [symmetric] keys will be infeasible until computers are built ...
5
votes
4answers
833 views

Client side encryption - only web browser available

I am creating an enterprise application, the server side runs a whole set of different apps, On the client side, there is only a webpage, no applet or anything else. Unfortunately data created by the ...
2
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2answers
92 views

Understanding salted password hashing using Java

Context: I am using this tutorial and trying to understand and implement salted password hashing using Java. After spending some time on this topic, I figured out that the basic idea is to: Convert ...
0
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1answer
32 views

How is an epsilon of 1/1000 non-negligible?

Lately I've been studying cryptography and in the current course I'm taking we're reviewing statistical tests and how they can be used to determine if a pseudo-random generator is secure or not. ...
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2answers
51 views

Is there a way to give out secure tickets wihout storing them?

I'm building a website on which I want to make it very easy for users to create pages anonymously and later be able to come back and edit those pages. One way to do so is to give out confidential ...
0
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1answer
45 views

How to authenticate users?

I'm in the scenario that I'm planning a detailed description on "how to securely encrypt files" without putting too much in one Q/A. So, in a file-encryption scenario, what are the possible ways to ...
0
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1answer
14 views

Is the method of hardening the creation of a Cryptographically Generated Address (CGA) called hash extension

CGAs are sha1 hashes truncated to a 59 bit value. Along with a 3 bit security parameter they form a IPv6 address (more precisely the interface identifier). from wikipedia: The Sec parameter ...
2
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3answers
215 views

How can two parties compare whether a simple (5 letter) shared word matches, without disclosing their word to each other?

I'm having some trouble with this scenario, some advice would be great. The context is that a group of people have each been give a simple 5 letter word - for example: Alice: ACTOR Bob: JEANS Dan: ...
4
votes
2answers
226 views

Sharing RSA keys between PGP and SSH protocols: Does this pose a security risk?

If I generate a PGP subkey that only has the authentication capablity and use this to generate an SSH keypair to authenticate Git for example, does this pose a security threat? When I do, should I ...
1
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1answer
33 views

Can DUKPT BDK be 192 bits?

All examples seem to be with 128 bits. Can it be 192 bits?
0
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2answers
86 views

Is there a cryptographic function that generates a reconizable visual pattern?

I have to build a system that will ultimately print a pass allowing access to a building. The validation of this ticket will be done manually (it can also be automatic but that's not likely at this ...
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votes
2answers
83 views

How is encryption broken [duplicate]

The title describes pretty well what I want to ask, because I just can't wrap my head around it. I understand the basics of breaking encrypted data with the method of kind-of-bruteforcing where you ...
5
votes
1answer
143 views

How secure is CertiVox M-PIN?

CertiVox have designed a system with the aim of "getting rid of passwords". Essentially the system authenticates users with two factors of authentication: A 4 digit PIN and a token stored within the ...
0
votes
1answer
124 views

Google Chrome obsolete cryptography

I have a apache server running and following configuration for ssl: Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains" SSLProtocol -all +TLSv1.2 SSLCompression Off ...
1
vote
1answer
50 views

Linux Kernel module signing

If the linux kernel is compiled to check for kernel modules signing, it checks the validity of the public key (X.509) w.r.t the current system time. For the first time the system is booting up, it ...
0
votes
1answer
96 views

What can I do if someone is using my IP address? [closed]

Another device in my network is using my IP address, what can he do if he is using my IP address? Is this a crime? Can him be caught by police or sue by Malaysia government?
3
votes
2answers
169 views

RSA public key and private key lengths

I'm having a problem understanding the size of an RSA public key and its private key pair. I saw different key sizes for RSA algorithm (512, 1024,... for example), but is this the length of public ...
2
votes
1answer
203 views

SSH Key: Ed25519 vs RSA

A lot of people recommend using Ed25519 instead of RSA keys for SSH. The introduction page of Ed25519 (http://ed25519.cr.yp.to/) says: [..] breaking it has similar difficulty to breaking [..] RSA ...
2
votes
2answers
110 views

Are hashes of hashes used for password storage in practice? Why/why not? [duplicate]

A naive developers might store a password in the database directly, which would then be compared directly with the password sent from a client. A more security conscious developer might instead store ...
2
votes
1answer
127 views

Is HTML5 sessionStorage secure for temporarily storing a cryptographic key?

Assume I am building a local web application (e.g. browser extension) in HTML5 to encrypt a database locally. Access to the database is controlled by a password and a cryptographic master key is ...
2
votes
1answer
33 views

How can the parallelization in CTR mode be attained?

I am using CTR mode to encrypt/decrypt files. Theoretically CTR mode is faster than CFB or CBC because of its individual operations on blocks. In my case CTR mode takes almost as long as CFB. How can ...
1
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2answers
61 views

Can I use AES CTR mode to encrypt files with same key and nonce?

I want to encrypt the files stored in SD card and I am using the CTR mode of AES to encrypt it. The key and IV are fixed. So each time I encrypt/decrypt I use the same key and nonce. Most of the ...
6
votes
3answers
160 views

Does TLS_FALLBACK_SCSV provide blanket protection against downgrade attacks?

The TLS_FALLBACK_SCSV flag was touted as a way to prevent POODLE, which abused the potential to downgrade to SSLv3 from TLS. Does the implementation of this flag prevent similar downgrade attacks ...
-2
votes
1answer
79 views

Crypto for penetration test [closed]

I'm a newbie but I want to become a penetration tester. I'm taking a course on cryptography but I'm wondering... how useful is crypto for penetration testing compared to other skills like operating ...
1
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0answers
48 views

What is the difference between XOR and poly-XOR? [closed]

What is the difference between XOR and poly-XOR in encryption?
-1
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1answer
102 views

Cryptowall encryption files

This is a question concerning the way the Cryptowall ransomware encrypts files on the victim's computer. Someone knows if it is possible to recover the encryption key comparing the encrypted file and ...
1
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1answer
57 views

Prevent padding oracle attack on key exchange process

I found in my searches that the padding oracle attack can be used against the RSA with PKCS1PAdding or OAEP padding, and I used this algorithm for a symmetric key exchange. How can I prevent a padding ...
4
votes
2answers
92 views

Can the intended recipient be derived from a public-key encrypted ciphertext?

Assuming you have a list of possible recipients' public keys, and a ciphertext encrypted with one of those public keys, would it be possible to determine which public key?
0
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1answer
63 views

RSA: same symbols in plaintext give same symbols ciphertext?

I just started studying Information Security, but I just ran this program: http://www.sanfoundry.com/cpp-program-implement-rsa-algorithm/ and faced this strange thing. For small keys (don't try to ...
0
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0answers
45 views

Designing a security system for road pricing

It's my first semester with Information Security and I still feel a little lost. Sorry in advance for stupid mistakes I may have made. the examples in round brackets below are my own ideas, wrote ...