Signature generation with VB.net

[gihanchandima]

my program is developed by Vb.net 2005. and i need to call web API using VB.Net 2005 and it has to generate Signature. i'm generated signature but API retern Invalid Signature Error. sample signature code with PHP. here is the sample code. and how can i generate Signature using this example. really thanks for your help

1. Concatenate (order values based on the alphabetical order of the parameter names) all values to single string.

$dataString ​=​$amount​. ​$apiToken​.​$UserId​.​$requestId​;

2. Sign data string using RSA signing algorithm. Hashing algorithm is SHA256.

$pkeyid ​= openssl_pkey_get_private(​"file:///private_key".pem"​)​; $signResult ​= openssl_sign(​$dataString​, ​$signature​, ​$pkeyid​, ​OPENSSL_ALGO_SHA256 ​ )​;

3. Base64 encodes the generated signature

$signature ​= base64_encode(​$signature​)​; 

Thanks