(C# UWP/WinRT) RSA Encrypt RSA/ECB/OAEPWithSHA1AndMGF1Padding

Demonstrates how to RSA encrypt using RSA/ECB/OAEPWithSHA1AndMGF1Padding. Also demonstrates RSA/ECB/OAEPWithSHA-256AndMGF1Padding. Both of these terms are from Java's JCE. Note: In this context, "ECB" doesn't actually mean anything. It's a symmetric cipher mode that doesn't apply (or make sense) in this context.

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

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

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

// First load a public key object with a public key.
// In this case, we'll load it from a file.
Chilkat.PublicKey pubkey = new Chilkat.PublicKey();
bool success = pubkey.LoadFromFile("qa_data/pem/rsa_public.pem");
if (success != true) {
    Debug.WriteLine(pubkey.LastErrorText);
    return;
}

// RSA encryption is limited to small amounts of data. The limit
// is typically a few hundred bytes and is based on the key size and
// padding (OAEP vs. PKCS1_5).  RSA encryption is typically used for
// encrypting hashes or symmetric (bulk encryption algorithm) secret keys.
string plainText = "Time is an illusion. Lunchtime doubly so.";

// Import the public key to be used for encrypting.
success = rsa.ImportPublicKeyObj(pubkey);

// To get OAEP padding, set the OaepPadding property:
rsa.OaepPadding = true;

// To use SHA1 or SHA-256, set the OaepHash property
rsa.OaepHash = "sha256";
// for SHA1 --
rsa.OaepHash = "sha1";

// Indicate we'll want hex output
rsa.EncodingMode = "hex";

// Encrypt..
bool usePrivateKey = false;
string encryptedStr = rsa.EncryptStringENC(plainText,usePrivateKey);
Debug.WriteLine(encryptedStr);

// -------------------------------------------------
// Now decrypt with the matching private key.
Chilkat.Rsa rsa2 = new Chilkat.Rsa();

Chilkat.PrivateKey privKey = new Chilkat.PrivateKey();
success = privKey.LoadEncryptedPem("qa_data/pem/rsa_passwd.pem","passwd");
if (success != true) {
    Debug.WriteLine(privKey.LastErrorText);
    return;
}

success = rsa2.ImportPrivateKeyObj(privKey);

// Make sure we have the same settings used for encryption.
rsa2.OaepPadding = true;
rsa2.EncodingMode = "hex";
rsa2.OaepHash = "sha1";

string originalStr = rsa2.DecryptStringENC(encryptedStr,true);

Debug.WriteLine(originalStr);