Configure minimum RSA public key size

Supported on: At least Windows Server 2008 R2 or Windows 7

Registry

HKCU software\policies\microsoft\office\16.0\common\signatures

Options

minsigningrsabits enum
  • 0
  • 512
  • 768
  • 1024
  • 1536
  • 2048
  • 4096

Description

This policy setting allows you to configure the minimum number of RSA 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 RSA keys, unless the legacy or invalid RSA policy settings are configured. If the legacy or invalid RSA 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 RSA public key bits is set to 768, then this setting would default to 1024.