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

0
votes
1answer
33 views

How to verify the signature value in a SSL certificate?

According to RFC 3280 a certificate's basic syntax is Sequence := { tbsCertificate signatureAlgorithm signatureValue } In tbsCertificate, SubjectPublicKey is the public key of the ...
7
votes
3answers
994 views

What are the disadvantages of using public key cryptography when encrypting files? [duplicate]

I am wanting to encrypt a file with my public key, my friend told me that this is not a good idea but did not explain why. Can someone explain please.
0
votes
2answers
72 views

Is open source a good option for cryptography libraries? [closed]

I am trying to find good cryptography library to use with my project. I found open source options like openSSL and many more and also proprietory options like Intel Integrated Performance Primitives ...
0
votes
0answers
28 views

security authentication protocol [duplicate]

I'm "creating" a secure authentication protocol for my system and it is this: C-> S C S-> C N(once) C-> S Kc,aut[N] S-> AUT Ks,aut[C,Kc,aut[N]] AUT-> S Ks,aut[N] the line : X ...
-1
votes
0answers
29 views

Decrypt asymmetric private key with user password [closed]

I want to store sensitive information in database. My idea is I use RSA encryption I store public key in database and I would like to decrypt private key with user password and I also store this in ...
0
votes
2answers
120 views

Why don't the majority of today's malware use strong cryptography?

While reading another story of botnet takedown, my wondering has reached its apogee: Why don't malware authors use cryptography (encryption + signing) provided by good libraries when their creations ...
0
votes
0answers
41 views

How does Signal Protocol, used by `whatsapp` Works?

I want to understand the process of The Signal Algorithm, I have google it, but unable to find any good Article or tutorial. I want to understand the basic definition and functionality of The signal ...
1
vote
1answer
78 views

AES step by step

I can't seem to find an AES tutorial that starts from Unicode to Cipher text. All of the tutorials I found starts with 128 bit block already. Also, where do I start or what topics do I have to start ...
9
votes
2answers
807 views

techniques to detect & mitigate Crypto-ransomware?

Crypto ransomware attacks are the latest concerns for our organization, we need to verify if we are adequately protected from them & if affected, what are the generic mitigation measure? How do ...
1
vote
0answers
25 views

Create a signed file from the detached signature and the clear text file content

Assuming I have the following: data.txt data.ps7 (the detached signature) Can I generate the bundled signed file ? Any example would be great, using C#, Java or openssl or any other tool ?
1
vote
1answer
64 views

Cryptography behind RedHat subscription system (DRM)?

I have to do a project like a subscription manager. Ideally this should work like RedHat subscriptions. I'm having a hard time figuring out how it was implemented. How do they manage to avoid a ...
3
votes
1answer
86 views

What would be the repercussions in Information security, if someone found a way to factor large numbers quickly?

I am curious as to how exactly cyber-security would be affected if someone found a way to factor a large number quickly into its multiples. Let's assume that the time required for factorization is ...
4
votes
2answers
63 views

Signature that can only be verified by author and recipient - without pre-shared key

Desiderata: Alice wants to send a message to Bob for him to keep and to be able to refer to, such that Bob can be certain that the message came from Alice and was not tampered with. Alice also ...
3
votes
1answer
64 views

Is having a unique key to encrypt data not sufficient

Is it necessary to use a unique Initialization Vector (IV) with various cipher modes of operation (e.g. CBC) even though I use a unique key to encrypt plain text every time? It is said that an IV ...
-1
votes
1answer
63 views

What defines a “good” cryptographic algorithm? [closed]

The title pretty much says it all. I am looking for a formal definition of what a good crypto algorithm is. I cannot find anything online.
1
vote
1answer
65 views

how is public key being exchanged in asymmetric cryptography?

I understand that exchanging public key between parties is challenging task in asymmetric cryptography.Can someone help me understand how it is achieved?
1
vote
1answer
60 views

Hide data from user, but process it in application

Is there a way to hide the data that's received somehow from the user? In particular, I have some data that gets send from a webserver to an application. I want the application to process the data, ...
2
votes
1answer
56 views

Question on MAC(Message Authentication code)?

I am new to Cryptography and unable to understand clearly about MAC concept. As per MAC concept, Sender 'A' will encrypt the original message with symmetric key to create MAC1 value and then will send ...
3
votes
1answer
47 views

Is this good/secure method for client-server communication encryption?

Something came to my mind, and I wonder if this is proper method for client-server communication, and if this method is wide-used. On connection, client generates seed, encrypts it using asymmetric ...
2
votes
1answer
64 views

Can an attacker make in-app-purchases of my products in their app?

My iOS app needs to store a pre-shared secret. It cannot embedded within the App Bundle itself because it could be extracted by statically analysing the bundle. Apple's In-App-Purchase system allows ...
9
votes
1answer
173 views

How do EMV contactless cards protect against replay attacks?

I understand that standard RFID cards are vulnerable to replay attacks however, how do smart cards which are also contactless protect against replay attacks? Is this decided by the chip or by the ...
4
votes
2answers
58 views

Does EMV protect against sniffing PAN data from untrusted network?

I have received conflicting information in regards to the security of PAN data on the wire. Can this be sniffed with properly configured EMV at an atm? To quote from the link below: ...
2
votes
2answers
103 views

Are there any security advantages to the “TrueCrypt-Paradigm”?

TrueCrypt and its successors use a file format that has the special property, that it looks completely random, there's only a salt (which is random) and the cipher text (which looks random). I like to ...
3
votes
5answers
590 views

Why can passwords be used to encrypt data, but are less strong for authentication?

Encryption software is often password based. Even if the adversary gets your computer they can't get the data without knowing the password, and bruteforcing is infeasible. Websites use passwords to ...
1
vote
0answers
6 views

If we should not reuse primes in DH, shouldn't we not reuse ECDH elliptic curve properties? [migrated]

An article How is NSA breaking so much crypto? describes NSA's methods for breaking encryption. If a client and server are speaking Diffie-Hellman, they first need to agree on a large prime number ...
4
votes
1answer
127 views

What are active research topics in SSL/TLS?

I don't know whether it is right to ask a question here for my MTech dissertation. I thought there is no good place in the world where I can find security experts like here. I am interested in doing ...
2
votes
4answers
182 views

How could online encryption ever work? [duplicate]

I have recently read about the german enigma machine in WW2, It worked in a way that every day the machine configuration was sent per mail to the different operators. (I couldn't find official sources ...
0
votes
0answers
18 views

Decrypting keys wrapped by the Storage Root Key (SRK) of a TPM

Lets say I have a symmetric key wrapped with a storage root key (SRK) in a TPM. The SRK cannot be read by an attacker and so I perform the decryption and using the SRK and get the symmetric key in ...
1
vote
0answers
30 views

password aging, advantages and disadvantages [duplicate]

What is the advantages and disadvantages of password aging? Should we apply password aging policies? Thanks a lot.
2
votes
2answers
106 views

Where to store a pepper?

Assuming you're using a pepper in your password hashing, where should it be stored? I know you shouldn't store it in the database since it can easily be found there during a dump and the idea is to ...
1
vote
0answers
27 views

How to acquire the RSACryptoServiceProvider from the existing key container?

The Key containers of "Microsoft Base Smart Card Crypto Provider" are enumerated by setting PP_ENUMCONTAINERS flag for the function CryptGetProvParam(). The enumerated key containers are set to the ...
9
votes
1answer
136 views

How to compare key management strategies

Are there formal security definitions or frameworks to evaluate the quality of a key management scheme? Can I state something like "the key is XYZ-protected against a polynomial adversary given that ...
-3
votes
2answers
76 views

How do I know if a string is a cipher? [closed]

Hhello everyone. I have this string here: 697yqf3e3d9e3ej6d80y34y7jq Is it a cipher? I've tried to decode it as a cryptogram. It didn't work. How do I know if something is a cipher?
6
votes
2answers
1k views

Can I use SHA-512 hash as AES key?

I want to combine hashing and encryption for better security. So can I use a hash key generated from SHA-512 as a key in AES. For example, I have a password "secret", I calculate SHA-512 hash for it ...
3
votes
1answer
174 views

What would be a simple example of an asymmetric encryption function (asymmetric function)?

I am trying to understand RSA encryption but the algorithm seems quite complex. I know that with asymmetric encryption you use a key and a function to encrypt data and a different function to decrypt ...
0
votes
0answers
27 views

Secure transfer with proxy person in the middle

I am new to cryptography, so I would like some validation. I have an unusual use case that I haven't found described anywhere and would like to get some help validating my approach. Alice needs ...
1
vote
0answers
66 views

How to enable ECDHE in openjdk-1.8.0 in CentOS 6.7?

I have seen many posts that hinted ECDHE is available in the SunEC provider way back in openjdk-1.6.0. My environment: CentOS 6.7 with openjdk 1.8.0.71-1.b15.el6_7. No ECDHE. Made 2 changes in ...
1
vote
0answers
43 views

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 ...
2
votes
2answers
55 views

Does Thunderbird Enigmail plugin decrypt attached files?

From my research I have found out that you can easily send encrypted messages to one another using Enigmail. If first I encrypted a file,then attached it to an email, sending it through Enigmail to a ...
4
votes
3answers
126 views

How to decrypt a file encrypted under multiple public keys GPG

According to https://www.gnupg.org/gph/en/manual/x110.html To decrypt a message the option --decrypt is used. You need the private key to which the message was encrypted. Similar to the ...
-5
votes
1answer
90 views

Friend sent me a text and is encoded could anyone decode and tell me what it is? [closed]

I have been searching for hours to find out what this is but I have had no luck, would anyone mind helping? We are geeks so we do this all the time but I have never seen an encoding like this "Mlac ...
1
vote
1answer
36 views

GPG/Bitcoin usb gadget device

My idea is to take a raspberry pi zero (or any embedded linux board) and shove GPG inside it to encrypt/decrypt/sign data with RSA/ECC (for bitcoin) via USB. Like a USB thing that holds your ...
0
votes
1answer
53 views

How many hashes do I need to compute to get x collisions?

I know that you need to hash about 2^(N/2) to find a collision taking into account the birthday problem. But I'm not really sure about more than one collision, I mean, collisions with different ...
2
votes
1answer
54 views

The Requirements of a Cryptographic Algorithm [closed]

I remember reading a book on cryptography with a section detailing the objectives that modern cryptography must accomplish, one being that even if the algorithm is known, the method remains secure. ...
1
vote
1answer
80 views

Fast data integrity protection

I have a small device with a 16-bit (embedded) architecture, which transmits 1500 bytes every 3 milliseconds. This device has no built-in integrity protection, and it is possible to manipulate the ...
0
votes
1answer
40 views

Why the private key is not present for the certificate retrieved from the personal information exchange file?

certificate data is retrieved from the personal information exchange using the following Crypto API's hCertStore = PFXImportCertStore( &data, wszPassword, CRYPT_EXPORTABLE ); ...
1
vote
2answers
36 views

Client verification with PKCS#7

When a client sends you a pkcs#7 file to communicate with you, Is this because the file has their public key(certificate) and their chain and to avoid the confusion on your side what needs to be there ...
1
vote
3answers
98 views

Are there any problems with using CAMELLIA, IDEA and SEED based cipher suites on a web server in 2016?

I have recently seen CAMELLIA, SEED and IDEA cipher suites in use for HTTPS on a web server and am unsure what to suggest to the owner. The keys in use are all over 128 bits in length and standard ...
2
votes
1answer
108 views

How might a PIN based Web authentication scheme work?

I'm interested in implementing PIN based authentication for a web application, similar to what Facebook provides in their mobile web site. Here is the user flow: User visits the site for the first ...
1
vote
1answer
107 views

What is the format of an RSA public key?

I have this RSA public key from which I want to get Modulus and exponent part but not able to get the format in which it is encoded. Can someone please tell how to decode it? -----BEGIN PUBLIC ...