I have some question about implementation Multi-Prime RSA (More than 2 prime) in .NET
Is it possible to generate RSA key with Multi-Prime enabled using RSACryptoServiceProvider()?
Just reading [this article]:http://www.codeproject.com/Articles/10877/Public-Key-RSA-Encryption-in-C-NET but it use a standard RSA with 2 prime.
If I want to do Multi-Prime what should I do?
Thank you
I haven't seen any example of multi prime RSA in C#. The main place to look is of course key pair generation, if you cannot perform multi-prime generation then you cannot use multi-prime RSA. I've checked this on Bouncy Castle as well, and I don't see any RSA-MP key pair generation parameters.
So you either have to find an external library or you have to program it yourself. Note that RSA-MP is not standardized by NIST or specified in a universally recognized standard (such as RFC, PKCS#1) so that's a pretty good reason not to adopt it. Many runtimes only contain well recognized algorithms + a set of older algorithms, using NIST/FIPS as starting point.
Related
I have read round all the articles on StackOverflow and while a lot of them come close to the solution I want, none appear to work.
I simply want to take an existing private key to create a signature of a piece of data. This then becomes part of a data file which includes a header describing the parameters used. Next comes the signed version of a datafile, lastly the datafile itself (a hex file). Concatentation of files is not the issue, generating a certificate using the private and public key pairs I have is. The keys are of the format ("-----BEGIN PRIVATE KEY-----") I can generate signature files easily enough from scratch, but the software that will read the final file is expecting a 256 bye signature, whereas mine (using RSA-256) is only producing 32 byte signatures. It only has access to the public key for decryption and validation of the file signature.
I have come up across a number of errors such as keysets not being valid, not existing, the ComputeHash function not working and causing a crash. I suspect I need to provide more information to my RSACryptographicService through CSPParameters but am not sure what is necessary and sufficient to do so.
I would like to avoid digging into the mathematics behind the algorithm such as manually setting/reading the modulus / P/Q values etc. Can anyone propose a simple way to do this or tell me where I am going wrong? Code is available on request.
The comments you are getting saying 256-byte signature is too long are absurd. Ignore those.
256 bit (32 bytes) would be a very small signature, that cannot be correct. I believe what you're actually looking for is 2048-bit (256-byte) RSA signatures. Those are more sensible by today's standards (though a step larger doesn't hurt).
In terms of importing your key, and not setting key components manually, you should look into "PEM" format RSA keys. There are several nuget packages out there to handle them. Otherwise you can strip the header/footer and decode the base64 yourself and import the key components with some of the built in X509 classes.
.NET does not natively support PEM format keys, and as such, I recommend using a reputable crypto library such as BouncyCastle, as they support PEM key parsing in their RSA algorithms.
This existing stackoverflow link describes how to import keys in BouncyCastle:
Reading PEM RSA Public Key Only using Bouncy Castle
I do not usually work with encryption but I need to use AES-GCM algorythm in C# with 128-bit blocks and 256-bit key.
I already read many articles about it but I can't find a valid solution.
Maybe:
https://github.com/lukemerrett/Bouncy-Castle-AES-GCM-Encryption / BouncyCastle
or
https://blogs.msdn.microsoft.com/shawnfa/2009/03/17/authenticated-symmetric-encryption-in-net/
Can be valid solutions? Is there something already present in the Framework?
Is it possible to implement the same solution in ASP.NET 2.0? (I found: https://msdn.microsoft.com/it-it/library/system.security.cryptography.rijndaelmanaged(v=vs.110).aspx)
I've been tasked with adding in a system that allows my company to encrypt files so that we can send them to a third party and they can run some operations on our data. The third party has given me a public key in this format,
-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: GnuPG v2.0.18 (Darwin)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=k/9l
-----END PGP PUBLIC KEY BLOCK-----
Can I stick this text string directly into say the RSACryptoServiceProvider class in C# as the public key? Or is there more to it than that? I haven't worked with PGP before, and I'm trying to know what I need to do in order to get data encrypted using this key.
Although OpenPGP takes advantage of RSA and other standard algorithms, you cannot use the default C# RSACryptoServiceProvider. RSA is only one possible algorithm for OpenPGP, and furthermore you need some symmetric encryption algorithm like AES (which would also be available). But there are further problems: you'd need to implement a generator for the OpenPGP message format, and OpenPGP defined its own cipher mode. Implementing all this on your own will not only be a hassle involving incompatibilities (an incomplete list exists in the RFC, but also has lots of ways to include security issues (and a bunch of further interesting attacks have been proposed and mitigated with existing implementations like GnuPG).
If you want to use OpenPGP from C#, in the end it boils down to following alternatives:
use GnuPG through GPGME (but the wrapper still seems to be in alpha state),
use BouncyCastle which has native implementations of several cryptographic protocols including OpenPGP for both C# and Java, but the C#-implementation seems to be less wide-spread and is not as capable,
SharpPrivacy is another implementation, but seems dead
interface the GnuPG command line directly
All of those have advantages and disadvantages. Probably BouncyCastle will be the best way to go, if it does not support the required features, you'll probably have to drop calling command GnuPG on the command line.
There seems to be a C# library for this on GitHub but it is a few years old. I am sure it can point you in the right direction if you want to implement your own PGP encryption.
https://github.com/da2ce7/SharpPrivacy
There is also a codeproject article about it but it is quite old and references a site that seems to not be up any more. Here is a link to that one for reference as well
http://www.codeproject.com/Articles/4284/SharpPrivacy-OpenPGP-for-C
.
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Closed 10 years ago.
Possible Duplicate:
Simple 2 way encryption for C#
I want to encrypt data in my C# program, but want to be able to decrypt it later. Does anyone know of any library or tool that I can download that will enable me to do that?
Take a look at the System.Security.Cryptography namespace. There's, for example, the TripleDESCryptoServiceProvider.
You can use Microsoft Enterprise Library there is an encryption block in it
If you take a look at the System.Security.Cryptography namespace in the documentation then you'll find classes for most of the common cryptographic systems.
There are two types of algorithm:
Public key (e.g. RSA) - you encrypt with a public key and then decrypt with a private key.
Symmetric key (e.g. AES, DES) - encryption and decryption is performed with the same key.
Which one to choose depends mainly on your situation. Symmetric key algorithms are typically used for encrypting data because they're faster, but that poses the problem of exchanging the key securely. If you can manually configure the endpoints of communication with the same key, then great. If not then you can either use public key to encrypt everything or - as is used in SSL, etc. - add in a handshake phase where the keys are exchanged via public key cryptography.
There is a built in class for Cryptography
System.Security.Cryptography.RSACryptoServiceProvider
Please check this link RSACryptoServiceProvider
After reading this post regarding the use ECC to implement the hashing using aa private key I set about trying to find an implementation of ECDH and came across BoucyCastle.
Unfortunately documentation is minimal (as in zerow!) and I'm unsure what I'm about to accomplish is completely correct/valid.
We want to simply hash 4 strings which will be the users registration information (Name, Company, their company ID and their account ID which are both 12 characters long) which will then compute a serial they can use to activate our software.
I have generated a key pair using PUTTYGEN.exe but I cannot workout how to apply this with BouncyCastle, which class can I use to get started? Are there any examples out there?
So far I've concatenated the information and computed a MD5 hash of it (using the .NET classes) I cannot use the new VISTA enhanced API functions as we target XP still - .NET 3.5.
Anyone have any ideas?
I think .NET has the RSACryptoServiceProvider class which is a full RSA implementation.
There's sample code for your particular application here:
http://www.codeproject.com/KB/security/xmldsiglic.aspx
In this example they use MS's sn.exe tool to create the key.
So far I've concatenated the information and computed a MD5 hash of it (using the .NET classes).....
That statement in itself worries me. MD5 is seriously crackable - not just theoretically but practically. Please, please don't use MD5 for secure hashing. Use SHA-256 or SHA-512 and here's why
Also the post you linked is not quite true - yes symmetric algorithms use the same key to encrypt/decrypt but public/private key is not a magic bullet.
1) Public/private key is slow
2) Most publicc/private algorithms just encrypt the symmetric key and then use symmetric encryption for the data because it's much faster
The point is that a good hashing algorithm is non-reversible and hence very difficult to crack so is perfectly fine for your purposes. However, I'd suggest using a SALT, which is a cryptographically random number to add to your user data then hash that data as it makes your data much safer against dictionary attacks ( where hackers use well know terms and variants to crack passwords )