C#

Encrypt with Chilkat, Decrypt with OpenSSL

See more OpenSSL Examples

Demonstrates how to RSA encrypt a string using Chilkat, and then shows the corresponding OpenSSL command to RSA decrypt. The OpenSSL command to decrypt is as follows:

openssl rsautl -decrypt -inkey VP_Private.pem -in rsa_encrypted.bin -out original.txt

C#

bool success = false;

//  This example requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

Chilkat.Rsa rsa = new Chilkat.Rsa();

//  Note: RSA encryption uses the public key.  
//  RSA decryption uses the private key.
//  The reason is that the public key can be freely provided to anybody.  This allows anybody
//  to send an encrypted message to the private key owner, and only the private key owner 
//  can decrypt.
Chilkat.PublicKey key = new Chilkat.PublicKey();

//  Load an RSA public key from a PEM file:
success = key.LoadFromFile("qa_data/pem/VP_Public.pem");
if (success == false) {
    Debug.WriteLine(key.LastErrorText);
    return;
}

//  Load the public key into the RSA object.
success = rsa.UsePublicKey(key);
if (success == false) {
    Debug.WriteLine(rsa.LastErrorText);
    return;
}

string strToEncrypt = "00000000;XYZ2-3BHQ-ABCD-MMVV;6MY1-GHJK-9LRR;0";

//  The LittleEndian property is false by default, but it is set here
//  anyway to show that LittleEndian byte ordering is required for OpenSSL compatibility.
rsa.LittleEndian = false;

bool usePrivateKey = false;
byte[] encryptedBytes = null;
encryptedBytes = rsa.EncryptString(strToEncrypt,usePrivateKey);
if (rsa.LastMethodSuccess == false) {
    Debug.WriteLine(rsa.LastErrorText);
    return;
}

//  The OpenSSL command to decrypt would be this:
//  openssl rsautl -decrypt -inkey VP_Private.pem -in rsa_encrypted.bin -out original.txt

Chilkat.FileAccess fac = new Chilkat.FileAccess();
success = fac.WriteEntireFile("qa_output/rsa_encrypted.bin",encryptedBytes);
if (success == false) {
    Debug.WriteLine(fac.LastErrorText);
    return;
}

Debug.WriteLine("RSA Encryption Succeeded.");