Why the 512-byte length limit on passwords?

[adobeDan]

I would like to use CredentialManager to save PEM-format RSA private key data (typically a few thousand bytes), but there is an explicit 512-char length limit in the module code. Is that from an underlying Window Credential Manager limitation?

[jrwarwick]

At a glance, it looks to me like the password with this limitation is stored in a "SecureString":
https://github.com/xxbiohazrdxx/PowerShell_Credential_Manager/blob/master/PSCredentialManager.Cmdlet/Cmdlets.cs#L219
and seemingly "The maximum length of a SecureString instance is 65,536 characters." https://docs.microsoft.com/en-us/dotnet/api/system.security.securestring?view=net-5.0#remarks
If I have my facts straight, then: no is not an underlying limitation.