== Why is this an issue?

The MD5 algorithm and its successor, SHA-1, are no longer considered secure, because it is too easy to create hash collisions with them. That is, it takes too little computational effort to come up with a different input that produces the same MD5 or SHA-1 hash, and using the new, same-hash value gives an attacker the same access as if he had the originally-hashed value. This applies as well to the other Message-Digest algorithms: MD2, MD4, MD6.


This rule tracks usage of the ``++System.Security.Cryptography.CryptoConfig.CreateFromName()++``, and ``++System.Security.Cryptography.HashAlgorithm.Create()++`` methods to instantiate MD5, DSA, HMACMD5, HMACRIPEMD160, RIPEMD-160 or SHA-1 algorithms, and of derived class instances of ``++System.Security.Cryptography.SHA1++`` and ``++System.Security.Cryptography.MD5++``.


Consider using safer alternatives, such as SHA-256, or SHA-3.

=== Noncompliant code example

[source,csharp]
----
var hashProvider1 = new MD5CryptoServiceProvider(); //Noncompliant
var hashProvider2 = (HashAlgorithm)CryptoConfig.CreateFromName("MD5"); //Noncompliant
var hashProvider3 = new SHA1Managed(); //Noncompliant
var hashProvider4 = HashAlgorithm.Create("SHA1"); //Noncompliant
----

=== Compliant solution

[source,csharp]
----
var hashProvider1 = new SHA256Managed();
var hashProvider2 = (HashAlgorithm)CryptoConfig.CreateFromName("SHA256Managed");
var hashProvider3 = HashAlgorithm.Create("SHA256Managed");
----

include::../see.adoc[]

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== Implementation Specification
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== Comments And Links
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