# 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.
```mermaid
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)
```


[Here's](https://mermaid.live/edit#pako:eNqFUtFqgzAU_RW5Ty3YorbamofCaDcGe1thD8OXoNcaiEkW46gr_fdFLWzDafMUzj33nJObe4FUZggEKvyoUaR4YPSkaZkIxx5FtWEpU1QYZ88ZCjPEj6g_USeir_SsxW7Xw-QGPCPnsmf0BcvoK-QGTDH2aO1yllKD9xmv7UMq48ykMkwKyueTvi_YPJ7TgooT3s93kALH3vmTwJmx3NF9DMzmk4MZ2E8Jv6FmedPJ_7arbMOoSye9Z6pAfVSYjtCemGBVgdnYeP9VGdD-qgxMHpTibWL7KwdqqDOz-6Yb9TOjgeBkB7hQoi4py-z6XlqFBEyBJSZA7DXDnNbcJJCIq6XS2shjI1IgRtfoQq0yO7vbtgPJKa8sajcayAXOQPwgWHprL_ZWwSbYBkHsQgNksVrHy224itZRHIaxF4VXF76ktAr-Mowib-P7YRBtN55t6uTeu2Lref0GEiMksQ)  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:

```
## Markdown Start ##

_Conventional TLS Handshake_

| 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.|
| 

## Markdown End ##
```


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.

```mermaid
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](https://mermaid.live/edit#pako:eNqFU01vwjAM_SuRTyAxVOigJYdJE2wa2rQDSDtMvUStO6KFJEtTtA7x35d-SKB1LT2lz8_v2Y5zhFglCBQy_MpRxrji7MOwfSSJ-zQzlsdcM2nJUnCUto1v0RzQtPH1Zr3BTIkqWIdriZu7uzqHNsATCqFqRh1wjDpCG6CPsUTnmfKYWbzO2JRdZpYMlLZcSSaGvb7PWDx8xzsmP_B6fSslsavPcwVkwFNi6jIwGfYOpmXfJ_yGhqdFJX9pl7mETpdKesn1Ds1WY9xBe-SSZztMusb7r0qLdlb5Y3OxKJS8KPWZa7K9fyUHJvJ6XOUfzwiT5VI1zVxkXZg0UHIW6Ny9e61FOSK3BitmGRm47TeFPl9Kq4PeDBjBHs2e8cQ9pmOpEIHd4R4joO6YYMpyYSOI5MlRWW7VtpAxUGtyHEGuE3dZzdsDmjKROdS9I6BH-Abqe_54EYST8HYxmwfeZAQF0Kk3nt5O5tOJHyy80J8tTiP4Ucrle-NwHgb-zNHDWeC77ErsvQqWjqdfiS1TYA) the Live Diagram.

## Explanation

Q: Create a rendition of the following using a Table expressed in Markdown that 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:
```
## Markdown Start ##

_NetID Lookup Extended TLS Handshake_

| 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.          |

## Markdown End ##
```

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
1. Use terms from Schema.org
1. Ensure each step is named via a schema:name attribute
1. Use schema:position and schema:nextItem for enhanced indexing and flow
1. Use hash-based IRIs ( with @base set to <> ) for subject and object denotation
1. 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 ##