Consider obsoleting RSA.EncryptValue, RSA.DecryptValue

[reflectronic]

RSA.EncryptValue and RSA.DecryptValue have been obsolete and non-working since .NET Framework 4.6 (and were removed initially from .NET Core). A comment in the .NET reference source suggests that the members should have been marked obsolete long ago, but weren't because for .NET Framework compatibility reasons. Since .NET doesn't have these issues anymore, adding these obsoletions should now be straightforward.

namespace System.Security.Cryptography;

public partial class RSA : AsymmetricAlgorithm
{
+   [Obsolete("RSA.EncryptValue and DecryptValue are not supported and throw NotSupportedException. Use RSA.Encrypt and RSA.Decrypt instead.")]
    public virtual byte[] EncryptValue(byte[] rgb);
    
+   [Obsolete("RSA.EncryptValue and DecryptValue are not supported and throw NotSupportedException. Use RSA.Encrypt and RSA.Decrypt instead.")]
    public virtual byte[] DecryptValue(byte[] rgb);
}

public partial class RSACryptoServiceProvider : RSA
{
+   [Obsolete("RSA.EncryptValue and DecryptValue are not supported and throw NotSupportedException. Use RSA.Encrypt and RSA.Decrypt instead.")]
    public override byte[] EncryptValue(byte[] rgb);
    
+   [Obsolete("RSA.EncryptValue and DecryptValue are not supported and throw NotSupportedException. Use RSA.Encrypt and RSA.Decrypt instead.")]
    public override byte[] DecryptValue(byte[] rgb);
}

[ghost]

Tagging subscribers to this area: @dotnet/area-system-security, @vcsjones
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Issue Details

---

RSA.EncryptValue and RSA.DecryptValue have been obsolete and non-working since .NET Framework 4.6 (and were removed initially from .NET Core). A comment in the .NET reference source suggests that the members should have been marked obsolete long ago, but weren't because for .NET Framework compatibility reasons. Since .NET doesn't have these issues anymore, adding these obsoletions should now be straightforward.

namespace System.Security.Cryptography;

public partial class RSA : AsymmetricAlgorithm
{
+   [Obsolete("RSA.EncryptValue and DecryptValue are not supported and throw NotSupportedException.")]
    public virtual byte[] EncryptValue(byte[] rgb);
    
+   [Obsolete("RSA.EncryptValue and DecryptValue are not supported and throw NotSupportedException.")]
    public virtual byte[] DecryptValue(byte[] rgb);
}

public partial class RSACryptoServiceProvider : RSA
{
+   [Obsolete("RSA.EncryptValue and DecryptValue are not supported and throw NotSupportedException.")]
    public override byte[] EncryptValue(byte[] rgb);
    
+   [Obsolete("RSA.EncryptValue and DecryptValue are not supported and throw NotSupportedException.")]
    public override byte[] DecryptValue(byte[] rgb);
}

Author:	reflectronic
Assignees:	-
Labels:	area-System.Security
Milestone:	-

[bartonjs]

Huh, I thought we had already done this. But, apparently not.

[bartonjs]

RSA.EncryptValue and RSA.DecryptValue have been obsolete and non-working since .NET Framework 4.6

Actually, they've never worked for built-in providers. They were abstract in .NET Framework 1.0 and RSACryptoServiceProvider threw a NotSupportedException. RSAPKCS1KeyExchangeFormatter is the only thing that hinted at what the method pair was supposed to do, namely the raw RSA public key operation and raw RSA private key operation.

All we did in 4.6 was change abstract to virtual+throw so we didn't have to keep declaring override+throw for RSACng (4.6), RSAOpenSsl (.NET Core 1.0) and RSASecurityTransforms (.NET Core 2.0, non-public)

[teo-tsirpanis]

@reflectronic can you reword the message to guide the users towards using Encrypt and specifying an RSAEncryptionPadding?

[terrajobst]

Video

• Since the method (and all derivatives) always throw, we should also hide it.

namespace System.Security.Cryptography;

public partial class RSA : AsymmetricAlgorithm
{
    [Obsolete("RSA.EncryptValue and DecryptValue are not supported and throw NotSupportedException. Use RSA.Encrypt and RSA.Decrypt instead.")]
    [EditorBrowsable(EditorBrowsableState.Never)]
    public virtual byte[] EncryptValue(byte[] rgb);
    
    [Obsolete("RSA.EncryptValue and DecryptValue are not supported and throw NotSupportedException. Use RSA.Encrypt and RSA.Decrypt instead.")]
    [EditorBrowsable(EditorBrowsableState.Never)]
    public virtual byte[] DecryptValue(byte[] rgb);
}

public partial class RSACryptoServiceProvider : RSA
{
    [Obsolete("RSA.EncryptValue and DecryptValue are not supported and throw NotSupportedException. Use RSA.Encrypt and RSA.Decrypt instead.")]
    [EditorBrowsable(EditorBrowsableState.Never)]
    public override byte[] EncryptValue(byte[] rgb);
    
    [Obsolete("RSA.EncryptValue and DecryptValue are not supported and throw NotSupportedException. Use RSA.Encrypt and RSA.Decrypt instead.")]
    [EditorBrowsable(EditorBrowsableState.Never)]
    public override byte[] DecryptValue(byte[] rgb);
}

[vcsjones]

@reflectronic were you interested in implementing this?

[bartonjs]

@danmoseley What's your interest in taking some extra obsoletions in RC1? (The methods have thrown NotImplementedException in inbox types since they were introduced in .NET Framework 1.0, so it's as low of potential usage as we could ever really hope to expect 😄)

[deeprobin]

If you want I can do that as well.
/cc @reflectronic @danmoseley