SHA-2 support on Windows XP

Hi all,

If you try to use any SHA-2 algorithm (SHA-256, SHA-384 and SHA-512) on Windows XP, you may get the following error when using i.e. CryptCreateHash: NTE_BAD_ALGID or -2146893816 or 0x80090008 or "Invalid algorithm specified" . Same algorithms are supported on Vista, though.

Can we use SHA-2 algorithms in Windows XP at all? The answer is yes, but it will depend on the CSP (Cryptographic Service Provider) that we use to perform the cryptographic operations.

According to our documentation, Windows XP SP3 supports all SHA-2 algorithms except SHA-224

Overview of Windows XP Service Pack 3
Implements and supports the SHA2 hashing algorithms (SHA256, SHA384, and SHA512) in X.509 certificate validation. This has been added to the crypto module rsaenh.dll.

Our "Microsoft Base/Strong/Enhanced Cryptographic Providers" are implemented on Rsaenh.dll. If you try to use CryptCreateHash with any SHA-2 Algid (CALG_SHA_256, CALG_SHA_384, CALG_SHA_512) and any of these CSP, you will still get a NTE_BAD_ALGID error on XP SP3. Why? The issue is that those Algid's are only valid with providers of type PROV_RSA_AES, and these CSP are of type PROV_RSA_FULL.

"Microsoft Enhanced RSA and AES Cryptographic Provider" (or "Microsoft Enhanced RSA and AES Cryptographic Provider (Prototype)" as it's called on Windows XP SP3) is implemented in rsaenh.dll and is of type PROV_RSA_AES.

Note that technically speaking, Microsoft AES Cryptographic Provider is just Microsoft Enhanced Cryptographic Provider with support for AES encryption algorithms.


If you open regedit.exe and go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Cryptography\Defaults, you will be able to see the available Providers in the system ("Microsoft Enhanced Cryptographic Provider v1.0", "Microsoft Enhanced RSA and AES Cryptographic Provider (Prototype)", etc.) and the Provider Types ("Type 001" which is "RSA Full (Signature and Key Exchange)", "Type 024" which is "RSA Full and AES"). For each Provider you will also see which dll implements (rsaenh.dll, etc.) it and its Provider Type (1, 24, etc.). For each Provider Type you will see the name of the default Provider for that type. On Vista, default Provider for PROV_RSA_AES is "Microsoft Enhanced RSA and AES Cryptographic Provider", and on XP is "Microsoft Enhanced RSA and AES Cryptographic Provider (Prototype)".


Regarding SHA-224 support, SHA-224 offers less security than SHA-256 but takes the same amount of resources. Also SHA-224 is not generally used by protocols and applications. The NSA's Suite B standards also do not include it. We have no plans to add it on future versions of our CSPs.

Fortunately, Microsoft's CryptoAPI is based on a model which allows us to use any CSP which implements any algorithm. So we don't and won't implement SHA-224 in our own CSPs, but that doesn't mean that we can't use SHA-224 at all on Windows. We just need a third-party CSP which implements it, or create our own.

I hope this helps.



Alex (Alejandro Campos Magencio)