Org.BouncyCastle.Crypto.DataLengthException: attempt to process message to long for cipher

[jaskcdem]

CryptographiesTexter.zip

I try to encrypt a url data, and decrypt it on another web page, like the CryptographiesTexter do
But I GOT Exception : Org.BouncyCastle.Crypto.DataLengthException: attempt to process message to long for cipher when decoding

Can someone tell me the code where need to change to fix It
I had GOOGLE and COPILOT whole two days.
still no any idea

[peterdettman]

I guess you get the exception because you try to decrypt a message that is too large for the RSA key you are using, but I don't know if it's a design issue or an implementation bug. You should create small example showing the input and the decryption key you are trying to use.

[jaskcdem]

one step test

two step test

both key use RsaKeyPairGenerator to create

[peterdettman]

The problem is in CryptographyHelper:

    public string Decrypt(string encryptData) => Encoding.UTF8.GetString(Crypto.Decrypt(Encoding.UTF8.GetBytes(encryptData)));

The encryptData that is passed to this method is in Base64 encoding, so it should be decoded from Base64 instead of UTF8:

    public string Decrypt(string encryptData) => Encoding.UTF8.GetString(Crypto.Decrypt(Convert.FromBase64String(encryptData)));