. Net (C #): signhash and verifyhash of RSA

The two methods are equivalent to signdata and verifydata, except that the input parameter is a hash value rather than the original data. That is to say, the RSA-encrypted hash function in signdata is self-calculated. While signhash requires us to calculate and then input parameters.

 

The only note is that the hash algorithm specified by the signhash (and verifyhash) method is a string object, but it is in the format of a hash algorithm identifier (OID. Therefore, another method is required: cryptoconfig. mapnameiid to convert a hash algorithm string into a hash algorithm identifier (OID.

 

Code:

// + Using system. Security. Cryptography

Using (var rsa = new rsacryptoserviceprovider ())

Using (VAR sha1 = sha1.create ())

{

// Raw data

VaR DATA = new byte [] {1, 2, 3 };

// Calculate the hash value

VaR hash = sha1.computehash (data );

 

// Use signhash. Use cryptoconfig. mapnametooid

VaR sighash = RSA. signhash (hash, cryptoconfig. mapnametooid ("sha1 "));

// Use signdata to pass in data directly (the hash value is calculated inside the function)

VaR sigdata = RSA. signdata (data, typeof (sha1 ));

 

// Output two signature data

Console. writeline (bitconverter. tostring (sighash ));

Console. writeline (bitconverter. tostring (sigdata ));

 

// Verify

Console. writeline (RSA. verifyhash (hash, "sha1", sighash ));

Console. writeline (RSA. verifydata (data, typeof (sha1), sigdata ));

}

 

Output:

Bytes

-Timeout

Slave-

Bytes

-69-97-d8-0c-f7-1d-01-ae-89-8c-be-fe-86-8c-81-24-aa-9d-8a-22-84

 

Bytes

-Timeout

Slave-

Bytes

-69-97-d8-0c-f7-1d-01-ae-89-8c-be-fe-86-8c-81-24-aa-9d-8a-22-84

 

True

True

 

The two methods can obtain the same signature data.