This policy setting allows you to configure the minimum number of DSA public key bits Office allows to create digital signatures. ...

This policy setting allows you to configure the minimum number of DSA public key bits Office allows to create digital signatures.        If you enable this policy setting, you can specify the minimum number of bits that can be used to create a digital signature. For example: 1024, 2048, etc.        If you disable or don't configure this policy setting, Office allows all DSA keys, unless the legacy or invalid DSA policy settings are configured. If the legacy or invalid DSA public key bits policy settings are configured, then the default for this setting will be the next larger value. For example, if the number of DSA public key bits is set to 768, then this setting would default to 1024.