Configure legacy hashing algorithm: registry value legacyhashalgUserHKCU\software\policies\microsoft\office\16.0\common\signatures

Policy ID: L_SelectDigitalSignatureLegacyHashingAlgorithm
Scope: User Configuration
Supported on: At least Windows Server 2008 R2 or Windows 7
Source: Microsoft 365 Apps / Office Administrative Templates (version 5568.1000)
Category: Microsoft Office 2016 › Security Settings › Digital Signatures

Registry

legacyhashalg

REG_SZUser

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

Enabled value: Depends on the option value
Element: -

Options
Item	Stored value
MD5	md5
SHA1	sha1
SHA256	sha256
SHA384	sha384

Apply with .reg · CMD · PowerShell

.reg

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\common\signatures]

; Options (use only one)
; MD5
"legacyhashalg"="md5"
; SHA1
"legacyhashalg"="sha1"
; SHA256
"legacyhashalg"="sha256"
; SHA384
"legacyhashalg"="sha384"

CMD

:: Options (use only one)

:: MD5
reg add "HKCU\software\policies\microsoft\office\16.0\common\signatures" /v "legacyhashalg" /t REG_SZ /d "md5" /f
:: SHA1
reg add "HKCU\software\policies\microsoft\office\16.0\common\signatures" /v "legacyhashalg" /t REG_SZ /d "sha1" /f
:: SHA256
reg add "HKCU\software\policies\microsoft\office\16.0\common\signatures" /v "legacyhashalg" /t REG_SZ /d "sha256" /f
:: SHA384
reg add "HKCU\software\policies\microsoft\office\16.0\common\signatures" /v "legacyhashalg" /t REG_SZ /d "sha384" /f

PowerShell

# Common: create the key
New-Item -Path 'HKCU:\software\policies\microsoft\office\16.0\common\signatures' -Force | Out-Null

# Options (use only one)
# MD5
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\common\signatures' -Name 'legacyhashalg' -PropertyType String -Value 'md5' -Force | Out-Null
# SHA1
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\common\signatures' -Name 'legacyhashalg' -PropertyType String -Value 'sha1' -Force | Out-Null
# SHA256
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\common\signatures' -Name 'legacyhashalg' -PropertyType String -Value 'sha256' -Force | Out-Null
# SHA384
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\common\signatures' -Name 'legacyhashalg' -PropertyType String -Value 'sha384' -Force | Out-Null