HowTo -- Using CHAT-GPT to Generate a Sequence Diagram & Knowledge Graph about the TLS Protocol using CHAT-GPT

Situation Analysis

According to Key Internet Statistics in 2023 (Including Mobile) - BroadbandSearch, there are 5.25 billion+ people on the internet (and growing) who are increasingly challenged by control over their identity – due to the fact that identity authenticity still challenges both the Internet and Web.

Transport Layer Security (TLS) is a globally supported protocol, deployed across every modern computing device, that adds identity authenticity and/or privacy to communications between parties. For instance, it is the crucial component that enables e-commerce.

Communications between the browser used by a shopper and the e-commerce services provided by Amazon.com (and others) is only possible using the server authentication aspect of this protocol.

Unbeknownst to most, the TLS protocol also has a client authentication aspect commonly known as the Client Certificate Authentication (TLS CCA) protocol which enables a server verify credentials presented by a browser on behalf of its user; this aspect of said protocol is crucial to addressing identity authenticity challenges that have afflicted both the Internet and Web since their respective inceptions.

In this post, I use CHAT-GPT to generate a Mermaid Sequence Diagram that illustrates the following:

  1. Conventional TLS CCA protocol flow
  2. Extended TLS CCA protocol flow – used by NetIDTLS (for any resolvable identifier) and WebID-TLS (for HTTP-based removable identifiers)

Note:
For maximum impact, especially in regards to generated Tables and Knowledge Graphs, you are encouraged to read this post using a browser that includes the OpenLink Structured Data Sniffer (OSDS) extension (available for Chrome, Edge, Firefox, Safari and others) – thereby enabling you lift the data and information generated into a live Semantic Web that can be saved to any DBMS that supports the SPARQL Query Language & Protocol.

CHAT-GPT Transcript

Q: Describe the TLS-handshake algorithm for Client Certificate Authentication using Mermaid Sequence Notation
A:
In this Mermaid sequence diagram, we describe the TLS handshake algorithm for Client Certificate Authentication. The main actors are the Client and the Server. The process includes the exchange of messages for establishing a secure connection, including the optional Client Certificate Authentication step.

sequenceDiagram
    participant Client
    participant Server

    Client->>Server: ClientHello
    Server->>Client: ServerHello
    Server->>Client: Certificate
    Server->>Client: CertificateRequest (optional)
    Server->>Client: ServerKeyExchange
    Server->>Client: ServerHelloDone
    Client->>Server: Certificate (if requested)
    Client->>Server: ClientKeyExchange
    Client->>Server: CertificateVerify (if Certificate sent)
    Client->>Server: ChangeCipherSpec
    Client->>Server: Finished
    Server->>Client: ChangeCipherSpec
    Server->>Client: Finished
    Client->>Server: ApplicationData (encrypted)
    Server->>Client: ApplicationData (encrypted)

Mermaid Sequence Diagram Visualization

Here’s the Live Diagram.

Explanation

Q: Present the following text in a code-block using a Table expressed in Markdown

ClientHello: The client initiates the handshake by sending a message containing the supported TLS version, a random value, and a list of supported cipher suites.
ServerHello: The server responds with its chosen TLS version, a random value, and the chosen cipher suite.
Certificate: The server sends its certificate, which contains the public key.
CertificateRequest (optional): The server requests the client’s certificate if it requires client authentication.
ServerKeyExchange: The server sends a key exchange message containing the necessary parameters for the client to generate the pre-master secret.
ServerHelloDone: The server indicates that it has completed the initial handshake messages.
Certificate (if requested): The client sends its certificate if the server has requested it.
ClientKeyExchange: The client sends the key exchange message containing the encrypted pre-master secret.
CertificateVerify (if Certificate sent): The client sends a digitally signed hash of all the handshake messages exchanged so far, using the private key associated with the provided client certificate.
ChangeCipherSpec: The client signals that all subsequent messages will be encrypted with the negotiated cipher suite and keys.
Finished: The client sends a message containing a hash of all the handshake messages exchanged so far, encrypted with the negotiated keys.
ChangeCipherSpec: The server signals that all subsequent messages will be encrypted with the negotiated cipher suite and keys.
Finished: The server sends a message containing a hash of all the handshake messages exchanged so far, encrypted with the negotiated keys.
ApplicationData (encrypted): The client and server can now exchange encrypted application data using the established secure connection.
Please note that this Mermaid sequence diagram is a high-level overview of the TLS handshake algorithm for Client Certificate Authentication. There are more detailed aspects and variations to the process that are not depicted here.

A:

Step # Message/Action Description
1 ClientHello Client initiates handshake with supported TLS version, random value, and list of supported cipher suites.
2 ServerHello Server responds with chosen TLS version, random value, and chosen cipher suite.
3 Certificate Server sends its certificate, which contains the public key.
4 CertificateRequest (optional) Server requests the client’s certificate if it requires client authentication.
5 ServerKeyExchange Server sends a key exchange message with necessary parameters for client to generate pre-master secret.
6 ServerHelloDone Server indicates completion of initial handshake messages.
7 Certificate (if requested) Client sends its certificate if the server has requested it.
8 ClientKeyExchange Client sends key exchange message with encrypted pre-master secret.
9 CertificateVerify (if sent) Client sends digitally signed hash of all handshake messages exchanged so far, using its private key.
10 ChangeCipherSpec Client signals that subsequent messages will be encrypted with the negotiated cipher suite and keys.
11 Finished Client sends a message with a hash of all handshake messages exchanged so far, encrypted with negotiated keys.
12 ChangeCipherSpec Server signals that subsequent messages will be encrypted with the negotiated cipher suite and keys.
13 Finished Server sends a message with a hash of all handshake messages exchanged so far, encrypted with negotiated keys.

Q: Redo, but extend the algorithm concluding the handshake after the following:
Lookup of Subject Alternative Name value if it is an IRI

A:
In this Mermaid sequence diagram, we extend the TLS handshake algorithm for Client Certificate Authentication by adding a lookup for the Subject Alternative Name (SAN) value if it’s an Internationalized Resource Identifier (IRI). The main actors are the Client, the Server, and a third participant - the IRI Resolver.

sequenceDiagram
    participant Client
    participant Server
    participant IRIResolver

    Client->>Server: ClientHello
    Server->>Client: ServerHello
    Server->>Client: Certificate
    Server->>Client: CertificateRequest (optional)
    Server->>Client: ServerKeyExchange
    Server->>Client: ServerHelloDone
    Client->>Server: Certificate (if requested)
    Client->>Server: ClientKeyExchange
    Client->>Server: CertificateVerify (if Certificate sent)
    Client->>Server: ChangeCipherSpec
    Client->>Server: Finished
    Server->>Client: ChangeCipherSpec
    Server->>Client: Finished

    Client->>IRIResolver: Lookup SAN value (if SAN is an IRI)
    IRIResolver->>Client: Resolved SAN value

    Client->>Server: ApplicationData (encrypted)
    Server->>Client: ApplicationData (encrypted)

Mermaid Sequence Diagram Visualization

Here’s the Live Diagram.

Explanation

Q: Create a rendition of the following, using a Table expressed in Markdown, that’s output to a code-block.

In this extended TLS handshake algorithm, the client looks up the SAN value if it’s an IRI after the handshake is completed. The IRI Resolver is a third participant that helps resolve the SAN value if needed.

1-12: Follow the same steps as in the original TLS handshake algorithm with Client Certificate Authentication.

Lookup SAN value (if SAN is an IRI): If the SAN value in the server certificate is an IRI, the client performs a lookup to resolve the IRI using the IRI Resolver.
Resolved SAN value: The IRI Resolver returns the resolved SAN value to the client.
15-16: The client and server continue exchanging encrypted application data using the established secure connection.
Please note that this Mermaid sequence diagram is a high-level overview of the extended TLS handshake algorithm for Client Certificate Authentication with SAN IRI lookup. There are more detailed aspects and variations to the process that are not depicted here.

A:

Step # Message/Action Description
1 ClientHello Client initiates handshake with supported TLS version, random value, and list of supported cipher suites.
2 ServerHello Server responds with chosen TLS version, random value, and chosen cipher suite.
3 Certificate Server sends its certificate, which contains the public key.
4 CertificateRequest (optional) Server requests the client’s certificate if it requires client authentication.
5 ServerKeyExchange Server sends a key exchange message with necessary parameters for client to generate pre-master secret.
6 ServerHelloDone Server indicates completion of initial handshake messages.
7 Certificate (if requested) Client sends its certificate if the server has requested it.
8 ClientKeyExchange Client sends key exchange message with encrypted pre-master secret.
9 CertificateVerify (if sent) Client sends digitally signed hash of all handshake messages exchanged so far, using its private key.
10 ChangeCipherSpec Client signals that subsequent messages will be encrypted with the negotiated cipher suite and keys.
11 Finished Client sends a message with a hash of all handshake messages exchanged so far, encrypted with negotiated keys.
12 ChangeCipherSpec Server signals that subsequent messages will be encrypted with the negotiated cipher suite and keys.
13 Finished Server sends a message with a hash of all handshake messages exchanged so far, encrypted with negotiated keys.
14 Lookup SAN (if SAN is an IRI) Client performs a lookup for the SAN value in the server certificate if it’s an IRI.
15 ApplicationData (encrypted) Client and server can now exchange encrypted application data using the established secure connection.

Q:
Generate an RDF-Turtle rendition, in HowTo and Step-By Guide form, using the following guidelines:

  1. Place code within ## Turtle Start ## and ## Turtle End ## block
  2. Use terms from Schema.org
  3. Ensure each step is named via a schema:name attribute
  4. Use schema:position and schema:nextItem for enhanced indexing and flow
  5. Use hash-based IRIs ( with @base set to <> ) for subject and object denotation
  6. Include DBpedia cross-references where such exist, confined to the schema:HowTo instance description, bearing in mind this is about PKI, Cryptography, Privacy, TLS, HTTPS, Digital Identity, Privacy, and Data Security

A:

## Turtle Start ##

@prefix schema: <http://schema.org/> .
@prefix dbo: <http://dbpedia.org/ontology/> .
@prefix dbr: <http://dbpedia.org/resource/> .

<#HowTo>
  a schema:HowTo ;
  schema:name "TLS Handshake and Secure Communication Process" ;
  schema:step <#Step1> ;
  dbo:subject dbr:Transport_Layer_Security, dbr:HTTPS, dbr:Public_key_infrastructure, dbr:Privacy, dbr:Data_security .

<#Step1>
  a schema:HowToStep ;
  schema:name "Client sends ClientHello message to the server" ;
  schema:position 1 ;
  schema:nextItem <#Step2> .

<#Step2>
  a schema:HowToStep ;
  schema:name "Server responds with ServerHello message and Certificate" ;
  schema:position 2 ;
  schema:nextItem <#Step3> .

<#Step3>
  a schema:HowToStep ;
  schema:name "Server optionally requests Certificate and sends ServerKeyExchange" ;
  schema:position 3 ;
  schema:nextItem <#Step4> .

<#Step4>
  a schema:HowToStep ;
  schema:name "Server sends ServerHelloDone message" ;
  schema:position 4 ;
  schema:nextItem <#Step5> .

<#Step5>
  a schema:HowToStep ;
  schema:name "Client responds with Certificate (if requested), ClientKeyExchange, CertificateVerify (if Certificate sent), ChangeCipherSpec, and Finished messages" ;
  schema:position 5 ;
  schema:nextItem <#Step6> .

<#Step6>
  a schema:HowToStep ;
  schema:name "Server responds with ChangeCipherSpec and Finished messages" ;
  schema:position 6 ;
  schema:nextItem <#Step7> .

<#Step7>
  a schema:HowToStep ;
  schema:name "Client looks up SAN value (if SAN is an IRI)" ;
  schema:position 7 ;
  schema:nextItem <#Step8> .

<#Step8>
  a schema:HowToStep ;
  schema:name "IRIResolver returns the resolved SAN value" ;
  schema:position 8 ;
  schema:nextItem <#Step9> .

<#Step9>
  a schema:HowToStep ;
  schema:name "Client and Server exchange ApplicationData (encrypted)" ;
  schema:position 9 .

## Turtle End ##

OpenLink Structured Data Sniffer Options

Related

NetIDTLS – a TLS CCA Extension

Building on my initial post which stopped at simply adding a Certificate Subject Identifier Lookup to the standard TLS CCA handshake, here’s a CHAT-GPT generated revision that addresses the NetIDTLS.

Transcript

Q: Describe the TLS-handshake algorithm for Client Certificate Authentication using Mermaid Sequence Notation, with the following protocol extensions after a successful handshake:

  1. Determine if Certificate’s Subject is denoted by an IRI via the Subject Alternative Name (SAN) field
  2. Lookup (de-reference) IRI, and if successful: search the resulting Profile Graph for matches to any of the following: Certificate Public Key or SHA-1 Fingerprint

Q: Redo, moving the following to the end of the sequence.
S->>C: Finished
Note over C,S: Encrypted Application Data exchanged
C->>S: CloseNotify (optional)
S->>C: CloseNotify (optional)

Q: Yes, but you can’t have duplicate entries for:
Redo, moving the following to the end of the sequence.
S->>C: Finished
Note over C,S: Encrypted Application Data exchanged
C->>S: CloseNotify (optional)
S->>C: CloseNotify (optional)

A:

sequenceDiagram
    participant C as Client
    participant S as Server
    C->>S: ClientHello
    S->>C: ServerHello
    S->>C: Certificate (Server)
    S->>C: CertificateRequest (optional)
    S->>C: ServerKeyExchange
    S->>C: ServerHelloDone
    C->>S: Certificate (Client, if requested)
    C->>S: ClientKeyExchange
    C->>S: CertificateVerify (if Certificate sent)
    C->>S: ChangeCipherSpec
    S->>C: ChangeCipherSpec
    Note over C,S: Handshake Successful
    Note over C,S: Protocol Extensions
    C->>S: Check Certificate SAN for IRI
    S->>C: IRI (if exists)
    C->>S: Lookup IRI (de-reference)
    S->>C: Profile Graph (if successful)
    C->>S: Search Profile Graph for Public Key or SHA-1 Fingerprint
    S->>C: Match Result (if any)
    S->>C: Finished
    Note over C,S: Encrypted Application Data exchanged
    C->>S: CloseNotify (optional)
    S->>C: CloseNotify (optional)

NetID-TLS Extended TLS Sequence Diagram

Here’s a Live Mermaid Sequence Diagram Link

Q: Generate a rendition using a Table expressed in Markdown that output to a code-block.
A:

Step Participant Description
1 Client ClientHello
2 Server ServerHello
3 Server Certificate (Server)
4 Server CertificateRequest (optional)
5 Server ServerKeyExchange
6 Server ServerHelloDone
7 Client Certificate (Client, if requested)
8 Client ClientKeyExchange
9 Client CertificateVerify (if Certificate sent)
10 Client ChangeCipherSpec
11 Server ChangeCipherSpec
12 - Handshake Successful
13 - Protocol Extensions
14 Client Check Certificate SAN for IRI
15 Server IRI (if exists)
16 Client Lookup IRI (de-reference)
17 Server Profile Graph (if successful)
18 Client Search Profile Graph for Public Key or SHA-1 Fingerprint
19 Server Match Result (if any)
20 Server Finished
21 - Encrypted Application Data exchanged
22 Client CloseNotify (optional)
23 Server CloseNotify (optional)

Q:
Generate an RDF-Turtle rendition, in HowTo and Step-By Guide form, using the following guidelines:

  1. Place code within ## Turtle Start ## and ## Turtle End ## block
  2. Use terms from Schema.org
  3. HowTo is titled “NetID+TLS Extended Handshake with Client Certificate Authentication Protocol”
  4. Ensure each step is named via a schema:name attribute
  5. Use schema:position and schema:nextItem for enhanced indexing and flow
  6. Use hash-based IRIs ( with @base set to <> ) for subject and object denotation
  7. Include DBpedia cross-references where such exist, confined to the schema:HowTo instance description, bearing in mind this is about PKI, Cryptography, Privacy, TLS, HTTPS, Digital Identity, Privacy, and Data Security

Q: Continue from step 16 all the way to fhe final step

A:

## Turtle Start ##
@prefix schema: <http://schema.org/> .
@prefix dbo: <http://dbpedia.org/ontology/> .
@base <> .

<#netid-tls-extended-handshake> a schema:HowTo ;
    schema:name "NetID+TLS Extended Handshake with Client Certificate Authentication Protocol" ;
    dbo:wikiPageCategory dbo:Public_key_infrastructure,
        dbo:Cryptography,
        dbo:Privacy,
        dbo:Transport_Layer_Security,
        dbo:HTTPS,
        dbo:Digital_identity,
        dbo:Data_security ;
    schema:step <#step1> .

<#step1> a schema:HowToStep ;
    schema:name "ClientHello" ;
    schema:position 1 ;
    schema:nextItem <#step2> .

<#step2> a schema:HowToStep ;
    schema:name "ServerHello" ;
    schema:position 2 ;
    schema:nextItem <#step3> .

<#step3> a schema:HowToStep ;
    schema:name "Certificate (Server)" ;
    schema:position 3 ;
    schema:nextItem <#step4> .

<#step4> a schema:HowToStep ;
    schema:name "CertificateRequest (optional)" ;
    schema:position 4 ;
    schema:nextItem <#step5> .

<#step5> a schema:HowToStep ;
    schema:name "ServerKeyExchange" ;
    schema:position 5 ;
    schema:nextItem <#step6> .

<#step6> a schema:HowToStep ;
    schema:name "ServerHelloDone" ;
    schema:position 6 ;
    schema:nextItem <#step7> .

<#step7> a schema:HowToStep ;
    schema:name "Certificate (Client, if requested)" ;
    schema:position 7 ;
    schema:nextItem <#step8> .

<#step8> a schema:HowToStep ;
    schema:name "ClientKeyExchange" ;
    schema:position 8 ;
    schema:nextItem <#step9> .

<#step9> a schema:HowToStep ;
    schema:name "CertificateVerify (if Certificate sent)" ;
    schema:position 9 ;
    schema:nextItem <#step10> .

<#step10> a schema:HowToStep ;
    schema:name "ChangeCipherSpec (Client)" ;
    schema:position 10 ;
    schema:nextItem <#step11> .

<#step11> a schema:HowToStep ;
    schema:name "Finished (Client)" ;
    schema:position 11 ;
    schema:nextItem <#step12> .

<#step12> a schema:HowToStep ;
    schema:name "ChangeCipherSpec (Server)" ;
    schema:position 12 ;
    schema:nextItem <#step13> .

<#step13> a schema:HowToStep ;
    schema:name "Finished (Server)" ;
    schema:position 13 ;
    schema:nextItem <#step14> .

<#step14> a schema:HowToStep ;
    schema:name "Determine if Certificate's Subject is denoted by an IRI via the SAN field" ;
    schema:position 14 ;
    schema:nextItem <#step15> .

<#step15> a schema:HowToStep ;
    schema:name "Lookup (de-reference) IRI, if successful" ;
    schema:position 15 ;
    schema:nextItem <#step16> .

<#step16> a schema:HowToStep ;
    schema:name "Search resulting Profile Graph for matches to Certificate Public Key or SHA-1 Fingerprint" ;
    schema:position 16 ;
    schema:nextItem <#step17> .

<#step17> a schema:HowToStep ;
    schema:name "Verify match and proceed with secure communication" ;
    schema:position 17 ;
    schema:nextItem <#step18> .

<#step18> a schema:HowToStep ;
    schema:name "Exchange encrypted application data using the established secure connection" ;
    schema:position 18 ;
    schema:nextItem <#step19> .

<#step19> a schema:HowToStep ;
    schema:name "Monitor the secure communication for potential issues" ;
    schema:position 19 ;
    schema:nextItem <#step20> .

<#step20> a schema:HowToStep ;
    schema:name "Detect any anomalies or security threats" ;
    schema:position 20 ;
    schema:nextItem <#step21> .

<#step21> a schema:HowToStep ;
    schema:name "Address detected issues and maintain secure communication" ;
    schema:position 21 ;
    schema:nextItem <#step22> .

<#step22> a schema:HowToStep ;
    schema:name "CloseNotify (Client, optional)" ;
    schema:position 22 ;
    schema:nextItem <#step23> .

<#step23> a schema:HowToStep ;
    schema:name "CloseNotify (Server, optional)" ;
    schema:position 23 .

## Turtle End ##

NetID-TLS Client Certificate Authentication Protocol Explainer (Revised Edition)

CHAT-GPT Transcript

NetID-TLS CCA extends the basic protocol by adding the following steps immediately after step 6:

  1. Locate Identifier value in the client certificates Subject Alternative Name (SAN) field
  2. Lookup (de-reference) Identifier to its associated Profile Graph (which can exist in a variety of forms including metadata embedded in an HTML based Link In Bio Page)
  3. Find at least one of the following in the Profile Graph: Certificate Fingerprint or Public Key

Q: Describe NetID-TLS CCA
A:
NetID-TLS CCA (Client Certificate Authentication) is an extended TLS authentication protocol that adds extra steps to locate an identifier in the client certificate and de-reference it to an associated Profile Graph. Here’s a step-by-step guide for the NetID-TLS CCA authentication sequence:

  1. Establish a connection: The client initiates a connection to the server by sending a “ClientHello” message, which includes the highest TLS version supported by the client, a list of supported cipher suites, and other extensions.

  2. Server response: The server responds with a “ServerHello” message, selecting a mutually supported TLS version and cipher suite. The server also sends its digital certificate, which contains its public key and information about the server’s identity, signed by a trusted Certificate Authority (CA).

  3. Request for client certificate: If the server requires CCA, it sends a “CertificateRequest” message to the client. This message may include a list of acceptable CAs that the server trusts to issue client certificates.

  4. Client certificate: If the client has a certificate issued by one of the acceptable CAs, it sends the certificate to the server in a “Certificate” message. If the client doesn’t have a suitable certificate or chooses not to send it, it can send an empty “Certificate” message or a “no_certificate” alert.

  5. Client key exchange and authentication: The client generates a pre-master secret and encrypts it with the server’s public key, then sends it to the server in a “ClientKeyExchange” message. The client also signs a piece of data derived from the handshake messages using its private key, and sends the signature in a “CertificateVerify” message, which allows the server to authenticate the client.

  6. Server authentication and key derivation: The server decrypts the pre-master secret using its private key and authenticates the client by verifying the signature in the “CertificateVerify” message. Both the client and the server derive a master secret from the pre-master secret and use it to generate symmetric encryption keys and MAC keys.

  7. Locate Identifier value: In the NetID-TLS CCA extension, the server locates the Identifier value in the client certificate’s Subject Alternative Name (SAN) field.

  8. Lookup (de-reference) Identifier: The server looks up the Identifier to its associated Profile Graph, which can exist in various forms, such as metadata embedded in an HTML-based Link In Bio Page.

  9. Find Certificate Fingerprint or Public Key: The server verifies the client’s identity by finding at least one of the following in the Profile Graph: Certificate Fingerprint or Public Key.

  10. Secure communication: The client and the server exchange “ChangeCipherSpec” messages, indicating that they will start using the symmetric encryption keys and MAC keys derived from the master secret. They then exchange “Finished” messages to confirm that the handshake has been successful. From this point on, the client and server can securely communicate using the established encryption and integrity protection.

  11. Connection termination: The client and server can exchange application data securely until either side decides to close the connection. A “close_notify” alert is sent by the party initiating the closure, and the other party responds with its own “close_notify” alert to confirm the connection termination.

Q: Redo using Mermaid Sequence notation.

A:

journey
    title NetID-TLS CCA Authentication Sequence
    section Establishing a connection
        Client-->Server: ClientHello
    section Server response
        Server-->Client: ServerHello
        Server-->Client: Server Certificate
    section Request for client certificate
        Server-->Client: CertificateRequest
    section Client certificate
        Client-->Server: Client Certificate (or empty/no_certificate)
    section Client key exchange and authentication
        Client-->Server: ClientKeyExchange
        Client-->Server: CertificateVerify
    section Server authentication and key derivation
        Server-->Client: (Derive keys from pre-master secret)
        Client-->Server: (Derive keys from pre-master secret)
    section NetID-TLS CCA extension
        Server-->Client: (Locate Identifier value in SAN)
        Server-->Client: (Lookup Identifier to associated Profile Graph)
        Server-->Client: (Find Certificate Fingerprint or Public Key in Profile Graph)
    section Secure communication
        Client-->Server: ChangeCipherSpec
        Server-->Client: ChangeCipherSpec
        Client-->Server: Finished
        Server-->Client: Finished
        Client-->Server: (Encrypted application data)
        Server-->Client: (Encrypted application data)
    section Connection termination
        Client-->Server: close_notify (or vice versa)
        Server-->Client: close_notify (or vice versa)

Mermaid User Journey Diagram

Here’s the live Mermaid User Journey diagram.

Q: Redo, using Mermaid Sequence notation.

A:

sequenceDiagram
    participant Client
    participant Server
    Client->>Server: ClientHello
    Server->>Client: ServerHello
    Server->>Client: Server Certificate
    Server->>Client: CertificateRequest
    Client->>Server: Client Certificate (or empty/no_certificate)
    Client->>Server: ClientKeyExchange
    Client->>Server: CertificateVerify
    Server->>Client: (Derive keys from pre-master secret)
    Client->>Server: (Derive keys from pre-master secret)
    Note over Server: NetID-TLS CCA extension
    Server->>Client: (Locate Identifier value in SAN)
    Server->>Client: (Lookup Identifier to associated Profile Graph)
    Server->>Client: (Find Certificate Fingerprint or Public Key in Profile Graph)
    Client->>Server: ChangeCipherSpec
    Server->>Client: ChangeCipherSpec
    Client->>Server: Finished
    Server->>Client: Finished
    Client->>Server: (Encrypted application data)
    Server->>Client: (Encrypted application data)
    Client->>Server: close_notify (or vice versa)
    Server->>Client: close_notify (or vice versa)

Mermaid Sequence Diagram

Here’s a live Link to the Mermaid Sequence Diagram.

Q: Redo, but presenting the guide in a code-block comprising a Markdown Table.
A:

Step Description
1 Establish a connection: The client initiates a connection by sending a “ClientHello” message to the server.
2 Server response: The server sends a “ServerHello” message, selects a cipher suite and sends its digital certificate.
3 Request for client certificate: The server sends a “CertificateRequest” message to the client.
4 Client certificate: The client sends its certificate to the server or an empty “Certificate” message.
5 Client key exchange and authentication: The client sends “ClientKeyExchange” and “CertificateVerify” messages.
6 Server authentication and key derivation: The server decrypts the pre-master secret and derives symmetric keys.
7 Locate Identifier value: The server locates the Identifier value in the client certificate’s SAN field.
8 Lookup (de-reference) Identifier: The server looks up the Identifier to its associated Profile Graph.
9 Find Certificate Fingerprint or Public Key: The server verifies the client’s identity using the Profile Graph.
10 Secure communication: The client and server exchange “ChangeCipherSpec” and “Finished” messages to secure the channel.
11 Connection termination: The client and server exchange “close_notify” alerts to close the connection.

Q:
Redo, but using RDF-Turtle rendition in HowTo and Step-By Guide form, in line with these guidelines:

  1. place code within ## Turtle Start ## and ## Turtle End ## block
  2. use terms from Schema.org
  3. ensure each step is named via a schema:name attribute
  4. use schema:position and schema:nextItem for enhanced indexing and flow
  5. relative hash-based IRIs ( e.g., <#> ) for subject and object denotation
  6. include DBpedia cross-references where such exist, bearing in mind this is about pki, tls, https, cryptography, privacy, email, identity, and privacy pegged to the schema:HowTo instance description

A:

## Turtle Start ##

@prefix schema: <http://schema.org/> .
@prefix dbpedia: <http://dbpedia.org/resource/> .
@prefix : <#> .

:HowToNetID-TLS_CCA
  a schema:HowTo ;
  schema:name "NetID-TLS CCA Authentication Sequence" ;
  schema:step :Step1 ;
  schema:about dbpedia:Transport_Layer_Security,
                dbpedia:Public_key_infrastructure,
                dbpedia:HTTPS,
                dbpedia:Cryptography,
                dbpedia:Privacy,
                dbpedia:Email,
                dbpedia:Digital_identity .

:Step1
  a schema:HowToStep ;
  schema:name "Establish a connection" ;
  schema:text "The client initiates a connection by sending a 'ClientHello' message to the server." ;
  schema:position 1 ;
  schema:nextItem :Step2 .

:Step2
  a schema:HowToStep ;
  schema:name "Server response" ;
  schema:text "The server sends a 'ServerHello' message, selects a cipher suite and sends its digital certificate." ;
  schema:position 2 ;
  schema:nextItem :Step3 .

:Step3
  a schema:HowToStep ;
  schema:name "Request for client certificate" ;
  schema:text "The server sends a 'CertificateRequest' message to the client." ;
  schema:position 3 ;
  schema:nextItem :Step4 .

:Step4
  a schema:HowToStep ;
  schema:name "Client certificate" ;
  schema:text "The client sends its certificate to the server or an empty 'Certificate' message." ;
  schema:position 4 ;
  schema:nextItem :Step5 .

:Step5
  a schema:HowToStep ;
  schema:name "Client key exchange and authentication" ;
  schema:text "The client sends 'ClientKeyExchange' and 'CertificateVerify' messages." ;
  schema:position 5 ;
  schema:nextItem :Step6 .

:Step6
  a schema:HowToStep ;
  schema:name "Server authentication and key derivation" ;
  schema:text "The server decrypts the pre-master secret and derives symmetric keys." ;
  schema:position 6 ;
  schema:nextItem :Step7 .

:Step7
  a schema:HowToStep ;
  schema:name "Locate Identifier value" ;
  schema:text "The server locates the Identifier value in the client certificate's SAN field." ;
  schema:position 7 ;
  schema:nextItem :Step8 .

:Step8
  a schema:HowToStep ;
  schema:name "Lookup (de-reference) Identifier" ;
  schema:text "The server looks up the Identifier to its associated Profile Graph." ;
  schema:position 8 ;
  schema:nextItem :Step9 .

:Step9
  a schema:HowToStep ;
  schema:name "Find Certificate Fingerprint or Public Key" ;
  schema:text "The server verifies the client's identity using the Profile Graph." ;
  schema:position 9 ;
  schema:nextItem :Step10 .

:Step10
  a schema:HowToStep ;
  schema:name "Secure communication" ;
  schema:text "The client and server exchange 'ChangeCipherSpec' and 'Finished' messages to secure the channel." ;
  schema:position 10 ;
  schema:nextItem :Step11 .

:Step11
  a schema:HowToStep ;
  schema:name "Connection termination" ;
  schema:text "The client and server exchange 'close_notify' alerts to close the connection." ;
  schema:position 11 .

## Turtle End ##