Bouncy Castle Decryption in c# from private key and encrytedtext

Question

Encrytped text is: wMXLjsRSfO1VngHqotJXoxygP1eTktr3gc3tuhdzXpqOy1N1V8/wflJuHkn1PX7Rf3/ccvL5vzPYYaKIm3s4IMhshrwVH3p4euprwRyNTvlBPLLmZ/b/wuTXkKqRdK81V9oHocIfxerivS4oIJfA4J6fMbtKom6IoE4GVhiAsJs=

My Private Key is:

  -----BEGIN RSA PRIVATE KEY-----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 yGNmcNFpgefjm4P4WrH81Ho8ImYp7QH3S35I36CtS1UGsj5OBSSj9ZAIGmkCQDI/
 xowjKMfamLckhg0PLnMJlVvyI8PVelnrIg0NpSTG2VtBsmFFi+Gk2gl/ayp3HEba
 lqPYWEWnjIQVXVnUD8kCQQDJpHSBSFQWRBRGHl2Oyy1SXiBYFdW2FH7+2c1WzN4P
 iKkmgOXqC2RfMD0aE/xtMe8F2zFhPKcARIvEvfneVjmT
 -----END RSA PRIVATE KEY-----

I am using Bouncy Castle in c# , when i decrypt using the encrytedtext and private key using below code:

keyPair = (AsymmetricCipherKeyPair)new PemReader(reader).ReadObject();
IAsymmetricBlockCipher cipher = new RsaEngine();
RsaKeyParameters privateKey = (RsaKeyParameters)keyPair.Private;
cipher.Init(false, keyPair.Private);
byte[] deciphered = cipher.ProcessBlock(bytesl, 0, bytesl.Length);
string decipheredText = utf8enc.GetString(deciphered);

I am getting decipheredText as

☻♣?????U??`?u????|???^H?|???☺????♦M>?→?&↔.0p?J??a?▼?S←$*▬T☼?  xQ??-??Ai9;??siqD??_???  ♥↓§?k?Ny??kr?U??↔z Mazher Ul Haq

but my actual string was "Mazher Ul Haq" , How to get actual string

Answer 1

Your "encrypted text" is actually base64 text. I suspect that if you convert that into non-base64 data first, you should be fine. If you've already got it as a string, that's as simple as:

byte[] binaryData = Convert.FromBase64String(base64Text);

If you need to convert it to a string first:

string base64Text = Encoding.ASCII.GetString(base64Binary);
byte[] binaryData = Convert.FromBase64String(base64Text);