Jun 17, 2014 Public/Private key in.net using C# is very easy. Dotnet framework provides several classes in System.Security.Cryptography namespace. RSACryptoServiceProvider is class which is used to generate public/private key pairs. This class provides several methods to generate keys and do encryption and decryption. Xiao Ling / February 27, 2014 October 29, 2019 / Security / C/C, OpenSSL, RSA 5 comments It is known that RSA is a cryptosystem which is used for the security of data transmission. This tutorial introduces how to use RSA to generate a pair of public and private keys on Windows. Encryption and Decryption in RSA. Example of RSA: Here is an example of RSA encryption and decryption with generation of the public and private key. Generate public and private key: Encryption and Decryption. How to use the RSA Algorithm in a C# Windows Forms application. Open Visual Studio. For the session opening, the client generates a 256-bits AES session key, and a 128-bits AES session IV (Initialisation Vector). The client sends a GSP SESSION INIT message to the server, encrypted with the client's RSA private key (that is, encrypted with the private key). In a number of situations security software involves the interaction between (desktop) applications and web interfaces. For (RSA) asymmetric encryption we use the C library of OpenSSL (version 1.0.
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Cryptographic digital signatures use public key algorithms to provide data integrity. When you sign data with a digital signature, someone else can verify the signature, and can prove that the data originated from you and was not altered after you signed it. For more information about digital signatures, see Cryptographic Services.
This topic explains how to generate and verify digital signatures using classes in the System.Security.Cryptography namespace.
Generating Signatures
Digital signatures are usually applied to hash values that represent larger data. The following example applies a digital signature to a hash value. First, a new instance of the RSACryptoServiceProvider class is created to generate a public/private key pair. Next, the RSACryptoServiceProvider is passed to a new instance of the RSAPKCS1SignatureFormatter class. This transfers the private key to the RSAPKCS1SignatureFormatter, which actually performs the digital signing. Before you can sign the hash code, you must specify a hash algorithm to use. This example uses the SHA1 algorithm. Finally, the CreateSignature method is called to perform the signing.
Due to collision problems with SHA1, Microsoft recommends SHA256 or better.
Signing XML Files
The .NET Framework provides the System.Security.Cryptography.Xml namespace, which enables you sign XML. Signing XML is important when you want to verify that the XML originates from a certain source. For example, if you are using a stock quote service that uses XML, you can verify the source of the XML if it is signed.
The classes in this namespace follow the XML-Signature Syntax and Processing recommendation from the World Wide Web Consortium.
Verifying Signatures
To verify that data was signed by a particular party, you must have the following information:
- The public key of the party that signed the data.
- The digital signature.
- The data that was signed.
- The hash algorithm used by the signer.
Generate Rsa Private Key C Key
To verify a signature signed by the RSAPKCS1SignatureFormatter class, use the RSAPKCS1SignatureDeformatter class. The RSAPKCS1SignatureDeformatter class must be supplied the public key of the signer. You will need the values of the modulus and the exponent to specify the public key. (The party that generated the public/private key pair should provide these values.) First create an RSACryptoServiceProvider object to hold the public key that will verify the signature, and then initialize an RSAParameters structure to the modulus and exponent values that specify the public key.
Generate Rsa Private Key Windows
The following code shows the creation of an RSAParameters structure. The
Modulus
property is set to the value of a byte array called modulusData
and the Exponent
property is set to the value of a byte array called exponentData
.After you have created the RSAParameters object, you can initialize a new instance of the RSACryptoServiceProvider class to the values specified in RSAParameters. The RSACryptoServiceProvider is, in turn, passed to the constructor of an RSAPKCS1SignatureDeformatter to transfer the key.
The following example illustrates this process. In this example,
hashValue
and signedHashValue
are arrays of bytes provided by a remote party. The remote party has signed the hashValue
using the SHA1 algorithm, producing the digital signature signedHashValue
. The RSAPKCS1SignatureDeformatter.VerifySignature method verifies that the digital signature is valid and was used to sign the hashValue
.C# Generate Rsa Private Key
This code fragment will display '
The signature is valid
' if the signature is valid and 'The signature is not valid
' if it is not.