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Bouncy Castle C # PGP Decryption Example

I look all day yesterday and I cannot find a working example of PGP decryption using Bouncy Castle in C #

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Finally he earned. The main problem that I encountered with other samples was the fact that I had a keyword in which I included the signing key, which appeared first when I tried to download the key for decryption. That's why I had to add ElGamalPrivateKeyParameters key ElGamalPrivateKeyParameters on the key.

Below is my code. Not very clean, but it works.

  private static PgpPrivateKey GetPrivateKey(string privateKeyPath) { using (Stream keyIn = File.OpenRead(privateKeyPath)) using (Stream inputStream = PgpUtilities.GetDecoderStream(keyIn)) { PgpSecretKeyRingBundle secretKeyRingBundle = new PgpSecretKeyRingBundle(inputStream); PgpSecretKey key = null; foreach (PgpSecretKeyRing kRing in secretKeyRingBundle.GetKeyRings()) { foreach (PgpSecretKey secretKey in kRing.GetSecretKeys()) { PgpPrivateKey privKey = secretKey.ExtractPrivateKey("1234567890".ToCharArray()); if (privKey.Key.GetType() == typeof (Org.BouncyCastle.Crypto.Parameters.ElGamalPrivateKeyParameters)) //Org.BouncyCastle.Crypto.Parameters.ElGamalPrivateKeyParameters { return privKey; } } } } return null; } public static void Decrypt(Stream input, string outputpath, String privateKeyPath) { input = PgpUtilities.GetDecoderStream(input); try { PgpObjectFactory pgpObjF = new PgpObjectFactory(input); PgpEncryptedDataList enc; PgpObject obj = pgpObjF.NextPgpObject(); if (obj is PgpEncryptedDataList) { enc = (PgpEncryptedDataList)obj; } else { enc = (PgpEncryptedDataList)pgpObjF.NextPgpObject(); } var akp = new AsymmetricKeyParameter(true); PgpPrivateKey privKey = GetPrivateKey(privateKeyPath); PgpPublicKeyEncryptedData pbe = enc.GetEncryptedDataObjects().Cast<PgpPublicKeyEncryptedData>().First(); Stream clear; clear = pbe.GetDataStream(privKey); PgpObjectFactory plainFact = new PgpObjectFactory(clear); PgpObject message = plainFact.NextPgpObject(); if (message is PgpCompressedData) { PgpCompressedData cData = (PgpCompressedData)message; Stream compDataIn = cData.GetDataStream(); PgpObjectFactory o = new PgpObjectFactory(compDataIn); message = o.NextPgpObject(); if (message is PgpOnePassSignatureList) { message = o.NextPgpObject(); PgpLiteralData Ld = null; Ld = (PgpLiteralData)message; Stream output = File.Create(outputpath + "\\" + Ld.FileName); Stream unc = Ld.GetInputStream(); Streams.PipeAll(unc, output); } else { PgpLiteralData Ld = null; Ld = (PgpLiteralData)message; //Stream output = File.Create(outputpath + "\\" + Ld.FileName); Stream output = File.Create(outputpath); Stream unc = Ld.GetInputStream(); Streams.PipeAll(unc, output); } } } catch (Exception e) { throw new Exception(e.Message); } }
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I had problems with the Ron Harlev decryption function containing the output file until the program was interrupted. I have added some examples of using Stream to solve this problem. I also replaced the coded passphrase in favor of the input argument. Hope someone finds this helpful.

 private static bool DecryptFile(Stream inputStream, string outputDir, char[] passPhrase, string privateKeyLoc) { try { using (var newStream = PgpUtilities.GetDecoderStream(inputStream)) { PgpObjectFactory pgpObjF = new PgpObjectFactory(newStream); PgpEncryptedDataList enc; PgpObject obj = pgpObjF.NextPgpObject(); if (obj is PgpEncryptedDataList) { enc = (PgpEncryptedDataList)obj; } else { enc = (PgpEncryptedDataList)pgpObjF.NextPgpObject(); } var akp = new AsymmetricKeyParameter(true); PgpPrivateKey privKey = GetPrivateKey(privateKeyLoc, passPhrase, logger); PgpPublicKeyEncryptedData pbe = enc.GetEncryptedDataObjects().Cast<PgpPublicKeyEncryptedData>().First(); using (Stream clear = pbe.GetDataStream(privKey)) { PgpObjectFactory plainFact = new PgpObjectFactory(clear); PgpObject message = plainFact.NextPgpObject(); if (message is PgpCompressedData) { PgpCompressedData cData = (PgpCompressedData)message; Stream compDataIn = cData.GetDataStream(); PgpObjectFactory o = new PgpObjectFactory(compDataIn); message = o.NextPgpObject(); if (message is PgpOnePassSignatureList) { message = o.NextPgpObject(); } PgpLiteralData Ld = null; Ld = (PgpLiteralData)message; using (Stream output = File.Create(outputDir + "\\" + Ld.FileName)) { Stream unc = Ld.GetInputStream(); Streams.PipeAll(unc, output); } } } } return true; } catch (Exception e) { throw new Exception(e.Message); return false; } }
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A good example of how to do this in a simple way: https://blog.bitscry.com/2018/07/05/pgp-encryption-and-decryption-in-c/

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