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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Connecting to Oracle Database from VBScript - Hiding Credentials

At work our first level support uses a ticket management system that allows us to add extra functionality via VBScripts that the application invokes. First level support also receives quite a few ...
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125 views

Why does the finance industry uses 2TDEA instead of 3TDEA?

Why does the finance industry uses 2TDEA instead of 3TDEA; is there any historical reason or technical limitations like the support by HSMs used in the industry? The paper referred to here says ...
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112 views

Efficacy of self-made ransomware protection

I was recently wondering about how to circumvent malware such as the infamous Cryptolocker a while back and was wondering about the efficacy of having a set of files with known content in a known ...
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4answers
997 views

Why secure encrypted data consistency by strong hashing?

Consider the SSH protocol: the SSH packet is like [data, SHA1(data)]. The packet is entirely encrypted by a block cipher. The question is, why do we need a strong hash to protect the packet ...
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84 views

Encrypting the salt with password [duplicate]

Salts are stored in the plain text and readily available with the hashed passwords if the password database is compromised. What if we encrypt the salt using password itself? Doesn't it make offline ...
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1answer
105 views

Key Exchange using RSA

I'm trying to do key exchange using the following scheme. Server generates an RSA-2048 key pair and sends the public part to the client Client generates an RSA-592 key pair (I have to use RSA-592 ...
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58 views

Full control on cryptography vs relying on external certificate [closed]

I have a question with regards to having full control on the cryptography which you will be using for your own application vs relying on external entities such as certification authorities? What are ...
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1answer
118 views

rolling code & keyless entry system [closed]

The security industry typically uses rolling code algorithms to authenticate sender & receivers in keyless entry systems, which is called RKE (ex: KeeLoq). In key-less smart key car system, The ...
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86 views

Link Layer authenticated encryption vs authentication

Many security articles discuss about adding an extra layer of security at the link layer by either authenticating the data at the link layer authenticating and encrypting it. If we have ...
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3answers
116 views

Is information security based entirely on mathematics [closed]

I started to show interest in information security few months ago, the more I read the more I think it's all about mathematics not information techonolgy. I mean the whole thing is based on encryption ...
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2answers
89 views

Real-world applications of Differential Privacy?

Differentially private techniques guarantee privacy while often permitting accurate answers ...this is something I have been reading up on lately as a means of preserving user ...
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4answers
2k views

Why should I sign data that's already encrypted? [duplicate]

My question is about the difference between signing and encrypting. Why would you still sign something if you are already going to PKI encrypt it? Doesn't the PKI encryption inherently provide ...
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42 views

Forward Secrecy not supported with referenced browsers?

I am running a scan against one of our servers from the Qualys SSL tester site and it says that my server "does not support forward secrecy with the referenced browsers". What exactly does that mean? ...
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3answers
175 views

Is there any security gain / risk by adding additional padding (beyond what is required) when using AES-256 to encrypt very short strings?

I would like to encrypt some authentication tokens using AES 256 (not tied to this algorithm but it seems to be a reasonable choice). These messages are usually very short at 128-256 bits. I'm ...
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1answer
373 views

How are TLSv1.0 ciphers negotiated as TLSv1.2?

I'm a little confused about something I am reading in Bulletproof SSL. "TLS 1.2 is the only protocol that allows suites to define their PRFs. This means that for the suites defined before TLS 1.2 ...
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2answers
90 views

Encrypting using the private key in Identity-Based Cryptography

In normal asymmetric crpyto like RSA, if Alice encrypts something using her private key, Bob can decrypt it using Alice's public key. Is the same possible in Identity-Based Cryptography, where the ...
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2answers
115 views

ECDSA ciphers and forward secrecy question about key exchange

I have heard that with forward secrecy that the ECDSA ciphers generate different keys for "each session" because they are not dependent on the private key of the server. My question is how is "each ...
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60 views

How does Spideroak manage encryption keys

I'm trying to understand the following from SpiderOak's engineering page (sorry I'm on a mobile phone so have no access to formatting functions like quote blocks): "SpiderOak uses a nested series of ...
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1answer
512 views

What is the deal with Valicert SSL root certificates?

Does anyone know what the status of the "Valicert Class 2 Validation Authority" root certificate is or what's going on with Valicert in general? I've heard that that cert has been deprecated, no ...
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1answer
60 views

What is the purpose of “g” -> generator of the multiplicative group

I am currently beginning to studying the different security protocols and came across the SRP secure remote password protocol. I manage to understand the mathematic formulas behind it and the ...
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0answers
28 views

Key management for hosting applications

We're looking to host a number of client applications in our environment. Some of those will use crypto, e.g. for ssl or database encryption and obviously we'll need to manage keys for that. I am ...
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0answers
38 views

How is this SHA-1 hash generated? [closed]

If you get a disposable email from say guerrillamail.com, and then fill out the forgot my password page at dahorta.org/app/index.php/cliente/resgatar_senha, it emails you a link to reset your ...
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1answer
100 views

Is there a secure way to create and distribute Shamir Secrets?

This Shamir Secret sharing utility consumes the secret key, and then generates N keys that must be manually distributed to each person. This is probably fine for most low-security situations, but not ...
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1answer
166 views

Password Storage with Jasypt StrongPasswordEncryptor vs PBKDF2

We are currently working on authentication for a web application. For password storage, we're using Jasypt StrongPasswordEncryptor with SHA-256 and tens of thousands of iterations. Going into the ...
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1answer
2k views

4096 bit RSA encryption keys vs 2048

Where do 4096 bit RSA keys for SSL certs currently stand in terms of things like CA support, browser support, etc? In the overall scheme of things is the increased security worth the risk of 4096 bit ...
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2answers
86 views

Typical mistakes when implementing digital signatures?

I am looking for a list of typical mistakes someone can make when implementing digital signatures for a software. And of course why they are mistakes and how an attacker could take advantage of them. ...
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2answers
86 views

Do DES keys have to be random?

In stream cipher (namely the OTP ) . The pad which the plain text is Xored with has to be random to achieve perfect secrecy , or psudorandom to ensure semantic security Dose this apply to DES or ...
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140 views

Did the “Malicious SHA-1” technique enable the NSA to insert a backdoor into SHA-1?

SHA-1 was standardized by the NSA. It appears to be possible to choose the constants in such a way that collisions can be derived easily. Yet, it is not easily possible to discover that the constants ...
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73 views

Public/Private key validation

Suppose I have this scenario: User --> Inputs License Key --> I validate it --> If success, good, move onto main window. If not, prompt the user to reenter the license key. The license key will not ...
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51 views

Payment Application Integration - Encryption or HMAC

Doing an integration with an online payment provider. Payment provider will be making a web request to my server to provide some information about the basket content. On my end there's no payment ...
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2answers
119 views

How does an insecure RNG affect cryptography, and how do I measure the corresponding loss of security?

Suppose a given random number generator has poor entropy, and is compressible by any compression algorithm (zlib, bzip2, lzma, etc). Specifically the issues with this RNG are: Bad entropy Bad seed ...
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2answers
110 views

Securing fingerprint templates stored on web authentication server

I have a multi-factor web authentication server, that in addition to regular passwords uses fingerprints for user authentication. Can anyone think of a security flaw in the following scenario: I ...
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1answer
245 views

Bitdefender Antivirus SSL Cert substitution

I am using Bitdefender AV 2013 ed and I have noticed that when the Scan SSL is enabled in the configuration BD will use a local certificate, as mentioned here. This modifies the cert chain with BD as ...
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1answer
90 views

Will obtaining password hash compromise derived encryption key?

I've been looking at how PBKDF is used to generate encryption key for AES. One thing I couldn't get my head around is that how those OS keep the encryption key safe apart from using hardware modules. ...
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4answers
212 views

Using a Public-Key-Encryption browser side to avoid PCI compliance

We're developing a web application in which certain not logged users (clients) need to send their credit card details to other users (merchants) - which, we'll assume, are PCI compliant. We are ...
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58 views

Uniqueness of name in cryptography

If I publish my public key (I think I understand how this works, I'm still learning encryption) and I have a common name, could this leas to problems at all? OR does the email part guarantee that this ...
43
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1answer
4k views

How does a SIM card prevent cloning?

I have read a few articles about SIM cards, stating that the chip inside them uses some cryptographic magic to prevent people from cloning your number. This to me seems borderline impossible, given ...
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2answers
99 views

Related-password hash security

Say we are given a strong cryptographic hash function hash(), a strong completely random password of 15 characters pass15, two single-character salt values salta, saltb. We compute the hashes hasha, ...
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2answers
68 views

Is there something similar to pseudorandom generators but in the opposite direction?

Pseudorandom generators (PRG) are functions that takes a random small input (called the Seed) and maps it into much larger output . However, the mapping process must be unpredictable in order for the ...
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2answers
74 views

How to generate a superkey to decrypt strings

I'm working on an application where users have a key or password generated by me that is used to encrypt a string. Each user has their personal key, and no user should be able to decrypt another ...
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1answer
132 views

How easy is it to crack this encryption algorithm? [closed]

When I was about 13 or 14 years old, I was a little interested in cryptography (which is, after all, an interesting field). I learnt quite a lot since that time (it has been about 8 years since then), ...
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1answer
36 views

Can any ECC field element be safely serialized as “compressed” and then restored as uncompressed?

I have a library that stores all its ECC Field Elements in uncompressed form, in a bloated Base64 XML format, and storage has become a concern. (We want to support QR code as a form factor,etc) ...
2
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1answer
77 views

Would it be possible to add additional files to a password protected zip 2.0 file

So the scenario is this: I don't have the ability to determine/recover the master password for a production system that uses zip 2 archives. However, I need to be able to add new files to existing ...
2
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2answers
106 views

What problem does ECC seek to fix compared to RSA?

Elliptical Curve Cryptography (ECC) is one of the newest encryption schemes to challenge RSA cryptography. What problem does ECC seek to fix compared to RSA? Would you have any qualms with using ECC ...
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1answer
62 views

In TLS1.2 AES-GCM mode, what happened when input is not exactly the multiple of its block size?

I know that AES-GCM mode does not need padding, and its output are exactly the length of input data plus the tagging. But I am a little bit lost, as AES itself is block cipher, it could only operate ...
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1answer
550 views

good books for learning network and web security? [closed]

I am reading "Hacking The Art of Exploitation" book . i have read till chapter 2 programming but most of it has gone above my head . I want to learn basically cryptography , network security and web ...
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2answers
139 views

Cryptography protocol suitable for two-way radio communications

Specifically talking about walkie talkie radio networks. Suppose there is a group of up to 16 persons, each equipped with such a unit. Typically, one person will be talking with one another ...
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36 views

Mobile App Processing Debit Card Transactions

I am creating a mobile app for iPhone and Android and the respective API that will be exposed to support the operations. This operations will require the customer to type the PIN to complete the ...
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2answers
148 views

What is the collision likelihood of MD5 when non-numeric values are removed?

Start with a unique identifier String macAddress = "CC:3A:61:24:D6:96"; Hash the identifier via MD5 implementation String hash = md5(macAddress); //bd37f780e10244cf28810b969559ad5b Remove all ...
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1answer
50 views

Сompromised client.p12 file in OpenVPN

I'm not clearly understand technologies behind OpenVPN, so I have a question about OpenVPN security: What if I have client.p12 (PKCS#12) file and this file was leaked (with export password) to some ...