CA5384: Do not use digital signature algorithm (DSA)
Property | Value |
---|---|
Rule ID | CA5384 |
Title | Do not use digital signature algorithm (DSA) |
Category | Security |
Fix is breaking or non-breaking | Non-breaking |
Enabled by default in .NET 8 | No |
Cause
Using DSA in one of the following ways:
- Returning or instantiating derived classes of System.Security.Cryptography.DSA
- Using System.Security.Cryptography.AsymmetricAlgorithm.Create or System.Security.Cryptography.CryptoConfig.CreateFromName to create a DSA object.
By default, this rule analyzes the entire codebase, but this is configurable.
Rule description
DSA is a weak asymmetric encryption algorithm.
How to fix violations
Switch to an RSA with at least 2048 key size, ECDH or ECDsa algorithm instead.
When to suppress warnings
It is not recommended to suppress this rule unless for compatibility with legacy applications and data.
Suppress a warning
If you just want to suppress a single violation, add preprocessor directives to your source file to disable and then re-enable the rule.
#pragma warning disable CA5384
// The code that's violating the rule is on this line.
#pragma warning restore CA5384
To disable the rule for a file, folder, or project, set its severity to none
in the configuration file.
[*.{cs,vb}]
dotnet_diagnostic.CA5384.severity = none
For more information, see How to suppress code analysis warnings.
Configure code to analyze
Use the following options to configure which parts of your codebase to run this rule on.
You can configure these options for just this rule, for all rules it applies to, or for all rules in this category (Security) that it applies to. For more information, see Code quality rule configuration options.
Exclude specific symbols
You can exclude specific symbols, such as types and methods, from analysis. For example, to specify that the rule should not run on any code within types named MyType
, add the following key-value pair to an .editorconfig file in your project:
dotnet_code_quality.CAXXXX.excluded_symbol_names = MyType
Allowed symbol name formats in the option value (separated by |
):
- Symbol name only (includes all symbols with the name, regardless of the containing type or namespace).
- Fully qualified names in the symbol's documentation ID format. Each symbol name requires a symbol-kind prefix, such as
M:
for methods,T:
for types, andN:
for namespaces. .ctor
for constructors and.cctor
for static constructors.
Examples:
Option Value | Summary |
---|---|
dotnet_code_quality.CAXXXX.excluded_symbol_names = MyType |
Matches all symbols named MyType . |
dotnet_code_quality.CAXXXX.excluded_symbol_names = MyType1|MyType2 |
Matches all symbols named either MyType1 or MyType2 . |
dotnet_code_quality.CAXXXX.excluded_symbol_names = M:NS.MyType.MyMethod(ParamType) |
Matches specific method MyMethod with the specified fully qualified signature. |
dotnet_code_quality.CAXXXX.excluded_symbol_names = M:NS1.MyType1.MyMethod1(ParamType)|M:NS2.MyType2.MyMethod2(ParamType) |
Matches specific methods MyMethod1 and MyMethod2 with the respective fully qualified signatures. |
Exclude specific types and their derived types
You can exclude specific types and their derived types from analysis. For example, to specify that the rule should not run on any methods within types named MyType
and their derived types, add the following key-value pair to an .editorconfig file in your project:
dotnet_code_quality.CAXXXX.excluded_type_names_with_derived_types = MyType
Allowed symbol name formats in the option value (separated by |
):
- Type name only (includes all types with the name, regardless of the containing type or namespace).
- Fully qualified names in the symbol's documentation ID format, with an optional
T:
prefix.
Examples:
Option Value | Summary |
---|---|
dotnet_code_quality.CAXXXX.excluded_type_names_with_derived_types = MyType |
Matches all types named MyType and all of their derived types. |
dotnet_code_quality.CAXXXX.excluded_type_names_with_derived_types = MyType1|MyType2 |
Matches all types named either MyType1 or MyType2 and all of their derived types. |
dotnet_code_quality.CAXXXX.excluded_type_names_with_derived_types = M:NS.MyType |
Matches specific type MyType with given fully qualified name and all of its derived types. |
dotnet_code_quality.CAXXXX.excluded_type_names_with_derived_types = M:NS1.MyType1|M:NS2.MyType2 |
Matches specific types MyType1 and MyType2 with the respective fully qualified names, and all of their derived types. |
Example
The following code snippet illustrates the pattern detected by this rule.
Violation:
using System.Security.Cryptography;
class ExampleClass
{
public void ExampleMethod()
{
DSACng dsaCng = new DSACng();
}
}
Solution:
using System.Security.Cryptography;
class ExampleClass
{
public void ExampleMethod()
{
AsymmetricAlgorithm asymmetricAlgorithm = AsymmetricAlgorithm.Create("ECDsa");
}
}