Configure invalid hashing algorithm

This policy setting allows you to configure whether Office displays a digital signature as invalid when it contains specific hash algorithms.

If you enable this policy setting, you can specify the weakest hash algorithm that Office treats as invalid. If you enable this policy setting, you can specify any of the following algorithms:
- MD5
- SHA1
- SHA256
- SHA384

If you don't configure this policy setting, Office won't treat digital signatures as invalid because of the hashing algorithm.

For example, if you set MD5 as the invalid hashing algorithm Office treats MD5 signatures as invalid.

Supported on: At least Windows 7



  1. MD5
    Registry HiveHKEY_CURRENT_USER
    Registry Pathsoftware\policies\microsoft\office\16.0\common\signatures
    Value Nameinvalidhashalg
    Value TypeREG_SZ
    Valuemd5
  2. SHA1
    Registry HiveHKEY_CURRENT_USER
    Registry Pathsoftware\policies\microsoft\office\16.0\common\signatures
    Value Nameinvalidhashalg
    Value TypeREG_SZ
    Valuesha1
  3. SHA256
    Registry HiveHKEY_CURRENT_USER
    Registry Pathsoftware\policies\microsoft\office\16.0\common\signatures
    Value Nameinvalidhashalg
    Value TypeREG_SZ
    Valuesha256
  4. SHA384
    Registry HiveHKEY_CURRENT_USER
    Registry Pathsoftware\policies\microsoft\office\16.0\common\signatures
    Value Nameinvalidhashalg
    Value TypeREG_SZ
    Valuesha384


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