在envenedCms 中使用aes256gcm 算法加密/解密文件的问题。 我的选择是什么？

Question

I'm trying to replicate example from Java in c# with partial success

    CMSEnvelopedDataStreamGenerator gen = new CMSEnvelopedDataStreamGenerator();

    // NOTE: Uses the RECEIVER's PUBLIC encryption key
    gen.addRecipientInfoGenerator(new JceKeyTransRecipientInfoGenerator(remoteEncryptionCert, rsaesOaepIdentifier()));

    OutputEncryptor encryptor = new JceCMSContentEncryptorBuilder(CMSAlgorithm.AES256_GCM).setProvider(BC).build();

    try (FileOutputStream fileStream = new FileOutputStream(OUTPUT_FILE); OutputStream encryptingOutputStream = gen.open(fileStream, encryptor)) {
                
                //
                // write file
                //
 
                encryptingOutputStream.flush();
            }

I've tried so far

Using System.Security.Cryptography.Pkcs

public byte[] Encrypt(byte[] plainBytes, X509Certificate2 recipientCert)
{
    // create ContentInfo
    ContentInfo plainContent = new ContentInfo(plainBytes);

    // EnvelopedCms represents encrypted data
    Oid encryptAlgoOid = new Oid("2.16.840.1.101.3.4.1.46"); // AES-256-GCM, 
    //Oid encryptAlgoOid = new Oid("2.16.840.1.101.3.4.1.42"); // AES-256-CBC
    EnvelopedCms encryptedData = new EnvelopedCms(plainContent, new AlgorithmIdentifier(encryptAlgoOid));

    // add a recipient
    CmsRecipient recipient = new CmsRecipient(recipientCert);

    // encrypt data with public key of recipient
    encryptedData.Encrypt(recipient); //Throws "Unknown cryptographic algorithm."

    // create PKCS #7 byte array
    byte[] encryptedBytes = encryptedData.Encode();

    // return encrypted data
    return encryptedBytes;
}

error stack trace

Unknown cryptographic algorithm.
   at Internal.Cryptography.Pal.Windows.PkcsPalWindows.EncodeHelpers.CreateCryptMsgHandleToEncode(CmsRecipientCollection recipients, Oid innerContentType, AlgorithmIdentifier contentEncryptionAlgorithm, X509Certificate2Collection originatorCerts, CryptographicAttributeObjectCollection unprotectedAttributes)
   at Internal.Cryptography.Pal.Windows.PkcsPalWindows.Encrypt(CmsRecipientCollection recipients, ContentInfo contentInfo, AlgorithmIdentifier contentEncryptionAlgorithm, X509Certificate2Collection originatorCerts, CryptographicAttributeObjectCollection unprotectedAttributes)
   at System.Security.Cryptography.Pkcs.EnvelopedCms.Encrypt(CmsRecipientCollection recipients)
   at System.Security.Cryptography.Pkcs.EnvelopedCms.Encrypt(CmsRecipient recipient)
   at ConsoleApp1.Program.Encrypt() in Program.cs:line 91

Using Org.BouncyCastle.Cms

public byte[] Encrypt(X509Certificate2 recipientCert)
{
    // file stream
    FileStream fileEncrypted = new FileStream(pathToFile)

    CmsEnvelopedDataStreamGenerator gen = new CmsEnvelopedDataStreamGenerator();
    gen.AddKeyTransRecipient(recipientCert);

    var outEncryptedStream = gen.Open(fileEncrypted, "2.16.840.1.101.3.4.1.46"); 
    // Throws "KeyGenerator 2.16.840.1.101.3.4.1.46 not recognised." CmsEnvelopedDataGenerator doesn't 
    // have named constant for aes256gcm 

    return outEncryptedStream
}

error stack trace

KeyGenerator 2.16.840.1.101.3.4.1.46 not recognised.
   at Org.BouncyCastle.Security.GeneratorUtilities.GetKeyGenerator(String algorithm)
   at Org.BouncyCastle.Cms.CmsEnvelopedDataStreamGenerator.Open(Stream outStream, String encryptionOid)
   at ConsoleApp1.Program.Encrypt() in Program.cs:line 128

I have to make it work in a way so i can encrypt files with c# code and decrypt with java and vice versa.

What i noticed that i if i encrypt file in c# using Aes256CBC i can decrypt it in java, hows that possible? Does that mean that i implemented encryption wrong?

So what are mine options to make this work?

Answer 1

I'm sorry, as per https://github.com/bcgit/bc-csharp/blob/5bd4c8c70f80f1e7ead8e3c73459b78eb93d0ef7/crypto/src/security/GeneratorUtilities.cs it seems to be that AES-256-GCM mode is not available even in actual C# Bouncy Castle:

static GeneratorUtilities()
...
AddKgAlgorithm("AES256",
  "2.16.840.1.101.3.4.42",
  NistObjectIdentifiers.IdAes256Cbc,
  NistObjectIdentifiers.IdAes256Cfb,
  NistObjectIdentifiers.IdAes256Ecb,
  NistObjectIdentifiers.IdAes256Ofb,
  NistObjectIdentifiers.IdAes256Wrap);
...

Answer 2

根据Michael Fehr 的评论，AES-256-GCM 模块在 C# Bouncy Castle 中不可用，因此我们制作了 Java Api 并从我们的代码库中调用