How AD decides Kerberos encryption type per user/computer basis

Supposed that there is no GPO to enforce supported ciphers, on a per principal basis, it is determined as below:

If msDS-SupportedEncryptedTypes is populated, then use values defined in this attribute. It's a 5-bit flag

• bit 0   DES-CBC-CRC
• bit 1   DES-CBC-MD5
• bit 2   RC4-HMAC
• bit 3   AES128-CTS-HMAC-SHA1-96
• bit 4   AES256-CTS-HMAC-SHA1-96

If msDS-SupportedEncryptedTypes is NOT populated, then AD reads values in userAccoutControl. 

• if 0x200000 is set, DES will be used
• if 0x200000 is not set, default to RC4 for 2008/7 and later

Default behavior:

• Computer account: msDS-SupportedEncryptedTypes set. OS 2008/Win7 and newer: DES is disabled
• User account: msDS-SupportedEncryptedTypes is not set so RC4 is used see here, unless userAccountControl forces DES
• Referral Ticket/Trust object: higher of DES/RC4 that is mutually supported by client and authenticating domain. If both client and trust don't have any custom value set, cipher is RC4.
  
  NOTE/WARNING: If you enabled "AES" support on trust using GUI, only AES will be supported; RC4 will be disabled. If you want to add "AES" on top of RC4, use ksetup to change trust.

PS. Above behavior is always for Service Ticket.

    Since TGT is meant for DCs to read, it always uses what DC supports, and is irrelevant to what is defined on individual accounts.

Sample Script to find risky users

#Bitwise AND: 1.2.840.113556.1.4.803
#Bitwise OR : 1.2.840.113556.1.4.804
# 2097152 is 0x200000, bit mask for userAccountControl DES enforced
# 3 is 0b11, covers the last 2 bits of msDS-SupportedEncryptionTypes, which enables DES

# list users who
    # user object, and
    # enabled, and
        # supportedType set with DES, or
        # supportedTYpe not set but userAccountControl DES set
        
$ldapfilter=@("(&",`
    "(objectclass=user)",`                                                         # user Object
    "(!(userAccountControl:1.2.840.113556.1.4.803:=2))",`                          # enabled
    "(|",` 
        "(msDS-SupportedEncryptionTypes:1.2.840.113556.1.4.803:=3)",`              # DES defined in supportedType
        "(&",`                                                                     # or DES not set in supported type but in userAccountControl
            "(!(msDS-SupportedEncryptionTypes=*))",`                                   
            "(userAccountControl:1.2.840.113556.1.4.803:=2097152)",`
        ")",`
     ")",`
")")
$ldapfilter = $ldapfilter -join ""

$u=get-aduser -ldapfilter $ldapfilter -server foo.bar -Properties msDS-SupportedEncryptionTypes,enabled,userAccountControl,UseDESKeyOnly

Decentralized Identity (DID) - Verifiable Credential - Microsoft Verified ID

Traditional IDs are issued/owned by IdPs. From user's perspective, these IDs among different IdPs can be inconsistent, hard to maintain, and there is no guarantee of privacy, control, etc.

Decentralized ID lets a user owns his/her ID. Any other entity can then add claims to DID. For example, an employer can add employment claim to its employees' DIDs. Therefore, traditional IdPs no longer own IDs, they either become irrelevant to a person (if they can't add/verify claims about the said person), or they transform themselves to be claim issuer (if they know something about the holder) /verifiers (in this case, the old IdP is just a consuming party of DID model).  

"Claims" here is called "Verifiable Credentials"(VCs) in DID context. It's verifiable because it's digitally signed. Entities that assign/sign VCs are called Issuer.

DID creation, change, as well as claim history, are stored in a public, decentralized network. It can be tracked and verified without a centralized IdP. Such network is called Trust Systems. Examples include ION (Identity Overley Network) and DID:web. Trust System can be built on top of existing blockchain network such as Bitcoin.

For the model to work, there are implicit trusts listed below:

• Issuer trusts holder
• Verifier trusts issuer
• Holder trusts verifier

Set up a hybrid Azure AD lab

 General steps

1. Set up an on-premise AD with forest name johnfoo.tk
2. get a free domain from freenom (johnfoo.tk)
3. In Freenom, configure to use your own DNS server, pointing to on-prem DC IP
4. set up Azure AD 
5. create an Azure account for AAD Connect, make it Global Admin
6. create an AD service account for AD, give it DC Sync permission (or let AD Connect create for you)
7. Add and verify Custom Domain in AAD. Create the TXT record on your AD DNS. The "@" -named record required by Azure is equivalent of "(same as parent)" record in Windows DNS. Just leave the record name blank when create the TXT record.
8. Install AD Connect, enable
1. PHA (recommended, for auth fault tolerance, or PTA). Of course, use federation is also possible depending on if you are using ADFS right now on prem
2. Enable Seamless SSO (for on prem users SSO into Azure)
3. Be careful what attribute to use for join rule (?). UPN is a good candidate. Unless on prem users are already having email address, using mail for linkage will not work

Manually join Windows clients into Azure AD

1. Enable join/register option for regular users: AAD|Devices|Device Settings|Users may join devices to Azure AD
2. On Win client, Accounts, connect to work, then select "join this device to Azure AD", follow on screen instructions 
3. use "AzureAD\azureUPN" to log into the newly joined machine (e.g. AzureAD\jlan@johnfoo.tk)

Manually register Windows clients into Azure AD

1. Same steps as above, but in step 2, do not select "join this device to AZure AD", instead, just click on "next" button 

Create a B2C Tenant

1. Run "az provider register --namespace Microsoft.AzureActiveDirectory"
2. Follow on screen instruction

Grant Admin access to an Azure-joined machine

1. Tenant wide permission
1. Azure AD has a "Device administrators" role that is used for this purpose
2. Go to Devices | Device Settings | Manage Addtional local administrators on all Azure AD Joined devices | +assignment
2. Individual machine
1. Locally on the machine, using Account Settings to elivate a user
2. "net localgroup administrators /add "Contoso\username" for adding on-prem user
3. "net localgroup administrators /add "AzureAD\UserUpn" for adding Azure user
4. use MDM solution

Enabled Hybrid AD join

1. Run ADC, select Configure | additional tasks | Configure device options
2. Follow on screen instruction