Q:
Using a Mermaid Sequence Diagram, from the perspective of Apple Mail (iOS and macOS) where the digital certificate and associated private key are stored in the OS keychain, explain how S/MIME is used to send digitally signed emails.
A:
Here is a Mermaid sequence diagram illustrating how S/MIME is used to send digitally signed emails using Apple Mail (iOS and macOS), with the digital certificate and associated private key stored in the OS keychain:
```
sequenceDiagram
participant AppleMail
participant Recipient
participant Keychain
participant CertificateAuthority
AppleMail->>AppleMail: Compose email
AppleMail->>Keychain: Retrieve own public key, certificate, and private key
Keychain->>AppleMail: Send public key, certificate, and private key
AppleMail->>AppleMail: Compute hash of email content
AppleMail->>AppleMail: Encrypt hash with private key (digital signature)
AppleMail->>AppleMail: Attach digital signature and public key certificate to email
AppleMail->>Recipient: Send signed email
Recipient->>AppleMail: Request public key and certificate (if not attached)
AppleMail->>Recipient: Send public key and certificate
Recipient->>CertificateAuthority: Verify sender's certificate
CertificateAuthority->>Recipient: Certificate validation result
Recipient->>Recipient: Extract digital signature and email content
Recipient->>Recipient: Compute hash of received email content
Recipient->>Recipient: Decrypt digital signature using sender's public key (obtain original hash)
Recipient->>Recipient: Compare computed hash with decrypted hash (original hash)
Recipient->>Recipient: If hashes match, email integrity and sender authenticity are verified
```
[Here's](https://mermaid.live/edit#pako:eNqVVE1v2kAQ_SujvRQkF2ECGPsQCSU5VFUvidRDxWWzHtur2rvuek3iovz3zmJwTA2J4LTsvHnvzYd3x4SOkUWswj81KoH3kqeGFxsF9Cu5sVLIkisL67LM8QeX-TD0iHSQqOww9B0bkXGphpE7pHMiBbe4rm2mjbTN5oDrtL7e3nbnCO50UeoKAYvORh951IrIkDUStwj6RUFZP-dSwG9sPBDvoh5wFUNp5Jb-uGhLeCQ5VX5Ch72K6IMaasJlvMpAJ20tILSyXf8uZD4oYZrStpkv0mZ9TRjFMpWW51DJVHFbGxx_yLa2losMBlltMV2l_ULB6kut7zbg0CpHh3Ef3SFObTy6tatsX9EZ6KuOZAJKW-B7xxiPP5e_zDY0c24PI_iJRiYNVMSG5ks1pDiXduqkh4Atz2XMrdQKDFZ1boc-epkPr9ZwYS8M58zGXOD5f9cMCpRbvIbiHtulG1qpK6nS9wb1Wj7Sz5a-IKCepFJRktMff-qUE6loHce9JY9bB8e70RWs35I9CCsouBWZd6hbUtmpm9e-nW0FwGmIlESvk7snK1u3ARJj5rECDSXG9ErunN6GEbTADYvoGGPC3TzZRr0RlGj0U6MEi6yp0WN1SWM_PqosSnhe0S09gCzasVcW-dPV5CYMgyBYBYubZRiGHmtYFEx8f-WHs8XcnwbBwg_fPPZXa2LwJ7OVv5gt59PlchEu5nuyX_uQU3z7B1_XBqU) the live Mermaid Sequence Diagram.
# Explanation
Mermaid sequence diagram provides a high-level overview of how S/MIME is used to send digitally signed emails using Apple Mail (iOS and macOS) with the digital certificate and associated private key stored in the OS keychain. There are more detailed aspects and variations to the process that are not depicted here.
1. `AppleMail` composes the email.
2. `AppleMail` retrieves its own public key, certificate, and private key from the `Keychain`.
3. The `Keychain` sends the public key, certificate, and private key to `AppleMail`.
4. `AppleMail` computes a hash of the email content.
5. `AppleMail` encrypts the hash with the private key, creating a digital signature.
6. `AppleMail` attaches the digital signature and the public key certificate to the email.
7. `AppleMail` sends the signed email to the `Recipient`.
8. If the public key and certificate are not attached to the email, the `Recipient` requests them from `AppleMail`.
9. `AppleMail` sends the public key and certificate to the `Recipient`.
10. The `Recipient` verifies the sender's certificate with the `CertificateAuthority`.
11. The `CertificateAuthority` sends the certificate validation result to the `Recipient`.
12. The `Recipient` extracts the digital signature and email content.
13. The `Recipient` computes a hash of the received email content.
14. The `Recipient` decrypts the digital signature using the sender's public key, obtaining the original hash.
15. The `Recipient` compares the computed hash with the decrypted hash (original hash).
16. If the hashes match, the `Recipient` confirms the email's integrity and the sender's authenticity.
Q:
Also create a rendition of the steps using a Table in Markdown form that includes `## Markdown Start ##` and `## Markdown End ##`
A:
```
## Markdown Start ##
| Position | Step |
|----------|------------------------------------------------------------------------------------------|
| 1 | Compose email |
| 2 | Retrieve own public key, certificate, and private key from Keychain |
| 3 | Compute hash of email content |
| 4 | Encrypt hash with private key (digital signature) |
| 5 | Attach digital signature and public key certificate to email |
| 6 | Send signed email to Recipient |
| 7 | Request public key and certificate (if not attached) |
| 8 | Send public key and certificate |
| 9 | Verify sender's certificate with Certificate Authority |
| 10 | Extract digital signature and email content |
| 11 | Compute hash of received email content |
| 12 | Decrypt digital signature using sender's public key (obtain original hash) |
| 13 | Compare computed hash with decrypted hash (original hash) |
| 14 | Confirm email integrity and sender authenticity if hashes match |
## 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. 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. relative hash-based IRIs ( e.g., <#> ) for subject and object denotation
1. include DBpedia cross-references where such exist, bearing in mind this is about pki, cryptography, privacy, email, identity, and privacy
A:
```
## Turtle Start ##
@base <> .
@prefix schema: .
@prefix dbpedia: .
<#smimeProcess> a schema:HowTo ;
schema:name "S/MIME for Sending Digitally Signed Emails Using Apple Mail" ;
schema:about dbpedia:S\/MIME, dbpedia:Public_key_infrastructure, dbpedia:Email, dbpedia:Digital_signature, dbpedia:Identity_management, dbpedia:Privacy ;
schema:step <#step1> .
<#step1> a schema:HowToStep ;
schema:name "Compose email" ;
schema:position 1 ;
schema:nextItem <#step2> .
<#step2> a schema:HowToStep ;
schema:name "Retrieve own public key, certificate, and private key from Keychain" ;
schema:position 2 ;
schema:nextItem <#step3> .
<#step3> a schema:HowToStep ;
schema:name "Compute hash of email content" ;
schema:position 3 ;
schema:nextItem <#step4> .
<#step4> a schema:HowToStep ;
schema:name "Encrypt hash with private key (digital signature)" ;
schema:position 4 ;
schema:nextItem <#step5> .
<#step5> a schema:HowToStep ;
schema:name "Attach digital signature and public key certificate to email" ;
schema:position 5 ;
schema:nextItem <#step6> .
<#step6> a schema:HowToStep ;
schema:name "Send signed email to Recipient" ;
schema:position 6 ;
schema:nextItem <#step7> .
<#step7> a schema:HowToStep ;
schema:name "Request public key and certificate (if not attached)" ;
schema:position 7 ;
schema:nextItem <#step8> .
<#step8> a schema:HowToStep ;
schema:name "Send public key and certificate" ;
schema:position 8 ;
schema:nextItem <#step9> .
<#step9> a schema:HowToStep ;
schema:name "Verify sender's certificate with Certificate Authority" ;
schema:position 9 ;
schema:nextItem <#step10> .
<#step10> a schema:HowToStep ;
schema:name "Extract digital signature and email content" ;
schema:position 10 ;
schema:nextItem <#step11> .
<#step11> a schema:HowToStep ;
schema:name "Compute hash of received email content" ;
schema:position 11 ;
schema:nextItem <#step12> .
<#step12> a schema:HowToStep ;
schema:name "Decrypt digital signature using sender's public key (obtain original hash)" ;
schema:position 12 ;
schema:nextItem <#step13> .
<#step13> a schema:HowToStep ;
schema:name "Compare computed hash with decrypted hash (original hash)" ;
schema:position 13 ;
schema:nextItem <#step14> .
<#step14> a schema:HowToStep ;
schema:name "Confirm email integrity and authenticity" ;
schema:position 14 ;
schema:nextItem <#step15> .
<#step15> a schema:HowToStep ;
schema:name "Display verified email to the recipient" ;
schema:position 15 .
## Turtle End ##
```
_OpenLink Structured Data Sniffer Screenshot_
