public override bool TryEncrypt(ReadOnlySpan <byte> data, Span <byte> destination, RSAEncryptionPadding padding, out int bytesWritten)
{
ArgumentNullException.ThrowIfNull(padding);
ThrowIfDisposed();
int rsaSize = RsaPaddingProcessor.BytesRequiredForBitCount(KeySize);
if (destination.Length < rsaSize)
{
bytesWritten = 0;
return(false);
}
if (data.Length == 0)
{
if (padding.Mode != RSAEncryptionPaddingMode.Pkcs1 && padding.Mode != RSAEncryptionPaddingMode.Oaep)
{
throw new CryptographicException(SR.Cryptography_InvalidPaddingMode);
}
byte[] rented = CryptoPool.Rent(rsaSize);
Span <byte> tmp = new Span <byte>(rented, 0, rsaSize);
try
{
if (padding.Mode == RSAEncryptionPaddingMode.Oaep)
{
RsaPaddingProcessor.PadOaep(padding.OaepHashAlgorithm, data, tmp);
}
else
{
Debug.Assert(padding.Mode == RSAEncryptionPaddingMode.Pkcs1);
RsaPaddingProcessor.PadPkcs1Encryption(data, tmp);
}
return(Interop.AppleCrypto.TryRsaEncryptionPrimitive(
GetKeys().PublicKey,
tmp,
destination,
out bytesWritten));
}
finally
{
CryptographicOperations.ZeroMemory(tmp);
CryptoPool.Return(rented, clearSize: 0);
}
}
return(Interop.AppleCrypto.TryRsaEncrypt(
GetKeys().PublicKey,
data,
destination,
padding,
out bytesWritten));
}
private static bool TryEncrypt(
SafeRsaHandle key,
ReadOnlySpan <byte> data,
Span <byte> destination,
Interop.Crypto.RsaPadding rsaPadding,
RsaPaddingProcessor rsaPaddingProcessor,
out int bytesWritten)
{
int rsaSize = Interop.Crypto.RsaSize(key);
if (destination.Length < rsaSize)
{
bytesWritten = 0;
return(false);
}
int returnValue;
if (rsaPaddingProcessor != null)
{
Debug.Assert(rsaPadding == Interop.Crypto.RsaPadding.NoPadding);
byte[] rented = ArrayPool <byte> .Shared.Rent(rsaSize);
Span <byte> tmp = new Span <byte>(rented, 0, rsaSize);
try
{
rsaPaddingProcessor.PadOaep(data, tmp);
returnValue = Interop.Crypto.RsaPublicEncrypt(tmp.Length, tmp, destination, key, rsaPadding);
}
finally
{
CryptographicOperations.ZeroMemory(tmp);
ArrayPool <byte> .Shared.Return(rented);
}
}
else
{
Debug.Assert(rsaPadding != Interop.Crypto.RsaPadding.NoPadding);
returnValue = Interop.Crypto.RsaPublicEncrypt(data.Length, data, destination, key, rsaPadding);
}
CheckReturn(returnValue);
bytesWritten = returnValue;
Debug.Assert(returnValue == rsaSize);
return(true);
}
private static bool TryEncrypt(
SafeRsaHandle key,
ReadOnlySpan <byte> data,
Span <byte> destination,
Interop.AndroidCrypto.RsaPadding rsaPadding,
HashAlgorithmName?oaepHashAlgorithmName,
out int bytesWritten)
{
int rsaSize = Interop.AndroidCrypto.RsaSize(key);
if (destination.Length < rsaSize)
{
bytesWritten = 0;
return(false);
}
int returnValue;
if (oaepHashAlgorithmName != null)
{
Debug.Assert(rsaPadding == Interop.AndroidCrypto.RsaPadding.NoPadding);
byte[] rented = CryptoPool.Rent(rsaSize);
Span <byte> tmp = new Span <byte>(rented, 0, rsaSize);
try
{
RsaPaddingProcessor.PadOaep(oaepHashAlgorithmName.Value, data, tmp);
returnValue = Interop.AndroidCrypto.RsaPublicEncrypt(tmp.Length, tmp, destination, key, rsaPadding);
}
finally
{
CryptographicOperations.ZeroMemory(tmp);
CryptoPool.Return(rented, clearSize: 0);
}
}
else
{
Debug.Assert(rsaPadding != Interop.AndroidCrypto.RsaPadding.NoPadding);
returnValue = Interop.AndroidCrypto.RsaPublicEncrypt(data.Length, data, destination, key, rsaPadding);
}
CheckReturn(returnValue);
bytesWritten = returnValue;
Debug.Assert(returnValue == rsaSize, $"{returnValue} != {rsaSize}");
return(true);
}
// Conveniently, Encrypt() and Decrypt() are identical save for the actual P/Invoke call to CNG. Thus, both
// array-based APIs invoke this common helper with the "encrypt" parameter determining whether encryption or decryption is done.
private unsafe byte[] EncryptOrDecrypt(byte[] data, RSAEncryptionPadding padding, bool encrypt)
{
if (data == null)
{
throw new ArgumentNullException(nameof(data));
}
if (padding == null)
{
throw new ArgumentNullException(nameof(padding));
}
int modulusSizeInBytes = RsaPaddingProcessor.BytesRequiredForBitCount(KeySize);
if (!encrypt && data.Length != modulusSizeInBytes)
{
throw new CryptographicException(SR.Cryptography_RSA_DecryptWrongSize);
}
if (encrypt &&
padding.Mode == RSAEncryptionPaddingMode.Pkcs1 &&
data.Length > modulusSizeInBytes - Pkcs1PaddingOverhead)
{
throw new CryptographicException(
SR.Format(SR.Cryptography_Encryption_MessageTooLong, modulusSizeInBytes - Pkcs1PaddingOverhead));
}
using (SafeNCryptKeyHandle keyHandle = GetDuplicatedKeyHandle())
{
if (encrypt && data.Length == 0)
{
byte[] rented = CryptoPool.Rent(modulusSizeInBytes);
Span <byte> paddedMessage = new Span <byte>(rented, 0, modulusSizeInBytes);
try
{
if (padding == RSAEncryptionPadding.Pkcs1)
{
RsaPaddingProcessor.PadPkcs1Encryption(data, paddedMessage);
}
else if (padding.Mode == RSAEncryptionPaddingMode.Oaep)
{
RsaPaddingProcessor processor =
RsaPaddingProcessor.OpenProcessor(padding.OaepHashAlgorithm);
processor.PadOaep(data, paddedMessage);
}
else
{
throw new CryptographicException(SR.Cryptography_UnsupportedPaddingMode);
}
return(EncryptOrDecrypt(keyHandle, paddedMessage, AsymmetricPaddingMode.NCRYPT_NO_PADDING_FLAG, null, encrypt));
}
finally
{
CryptographicOperations.ZeroMemory(paddedMessage);
CryptoPool.Return(rented, clearSize: 0);
}
}
switch (padding.Mode)
{
case RSAEncryptionPaddingMode.Pkcs1:
return(EncryptOrDecrypt(keyHandle, data, AsymmetricPaddingMode.NCRYPT_PAD_PKCS1_FLAG, null, encrypt));
case RSAEncryptionPaddingMode.Oaep:
IntPtr namePtr = Marshal.StringToHGlobalUni(padding.OaepHashAlgorithm.Name);
try
{
var paddingInfo = new BCRYPT_OAEP_PADDING_INFO()
{
pszAlgId = namePtr,
// It would nice to put randomized data here but RSAEncryptionPadding does not at this point provide support for this.
pbLabel = IntPtr.Zero,
cbLabel = 0,
};
return(EncryptOrDecrypt(keyHandle, data, AsymmetricPaddingMode.NCRYPT_PAD_OAEP_FLAG, &paddingInfo, encrypt));
}
finally
{
Marshal.FreeHGlobal(namePtr);
}
default:
throw new CryptographicException(SR.Cryptography_UnsupportedPaddingMode);
}
}
}
// Conveniently, Encrypt() and Decrypt() are identical save for the actual P/Invoke call to CNG. Thus, both
// span-based APIs invoke this common helper with the "encrypt" parameter determining whether encryption or decryption is done.
private unsafe bool TryEncryptOrDecrypt(ReadOnlySpan <byte> data, Span <byte> destination, RSAEncryptionPadding padding, bool encrypt, out int bytesWritten)
{
if (padding == null)
{
throw new ArgumentNullException(nameof(padding));
}
using (SafeNCryptKeyHandle keyHandle = GetDuplicatedKeyHandle())
{
if (encrypt && data.Length == 0)
{
int bufSize = RsaPaddingProcessor.BytesRequiredForBitCount(KeySize);
byte[] rented = ArrayPool <byte> .Shared.Rent(bufSize);
Span <byte> paddedMessage = new Span <byte>(rented, 0, bufSize);
try
{
if (padding == RSAEncryptionPadding.Pkcs1)
{
RsaPaddingProcessor.PadPkcs1Encryption(data, paddedMessage);
}
else if (padding.Mode == RSAEncryptionPaddingMode.Oaep)
{
RsaPaddingProcessor processor =
RsaPaddingProcessor.OpenProcessor(padding.OaepHashAlgorithm);
processor.PadOaep(data, paddedMessage);
}
else
{
throw new CryptographicException(SR.Cryptography_UnsupportedPaddingMode);
}
return(TryEncryptOrDecrypt(keyHandle, paddedMessage, destination, AsymmetricPaddingMode.NCRYPT_NO_PADDING_FLAG, null, encrypt, out bytesWritten));
}
finally
{
CryptographicOperations.ZeroMemory(paddedMessage);
ArrayPool <byte> .Shared.Return(rented);
}
}
switch (padding.Mode)
{
case RSAEncryptionPaddingMode.Pkcs1:
return(TryEncryptOrDecrypt(keyHandle, data, destination, AsymmetricPaddingMode.NCRYPT_PAD_PKCS1_FLAG, null, encrypt, out bytesWritten));
case RSAEncryptionPaddingMode.Oaep:
IntPtr namePtr = Marshal.StringToHGlobalUni(padding.OaepHashAlgorithm.Name);
try
{
var paddingInfo = new BCRYPT_OAEP_PADDING_INFO()
{
pszAlgId = namePtr,
pbLabel = IntPtr.Zero, // It would nice to put randomized data here but RSAEncryptionPadding does not at this point provide support for this.
cbLabel = 0,
};
return(TryEncryptOrDecrypt(keyHandle, data, destination, AsymmetricPaddingMode.NCRYPT_PAD_OAEP_FLAG, &paddingInfo, encrypt, out bytesWritten));
}
finally
{
Marshal.FreeHGlobal(namePtr);
}
default:
throw new CryptographicException(SR.Cryptography_UnsupportedPaddingMode);
}
}
}
