# Files/Abbreviations

The list below provides you with a general description of what the different types of files mean. It can be confusing when there are many different file types, but this is the most simple way of explaining them:

## <mark style="color:red;">❊ PIV File Types</mark>

<table><thead><tr><th width="262">File Type</th><th>Description</th></tr></thead><tbody><tr><td><mark style="color:red;"><strong><code>.pub</code></strong></mark></td><td>Used for public keys and OpenSSH public keys.</td></tr><tr><td><mark style="color:red;"><strong><code>.key</code></strong></mark></td><td>Used to store private key.</td></tr><tr><td><mark style="color:red;"><strong><code>.pkcs12, .pfx, .p12</code></strong></mark></td><td>Used to store both public and private key / certificate information. Password protected.</td></tr><tr><td><mark style="color:red;"><strong><code>.pem</code></strong></mark></td><td>Used to store any type of key or cert, This includes public key, private key, certificate, or even the certificate signing request (csr).</td></tr><tr><td><mark style="color:red;"><code>.crt, .cer</code></mark></td><td>Used to store x509 certificates.</td></tr><tr><td><mark style="color:red;"><code>.csr, .req, .p10</code></mark></td><td>Used to store Certificate Signing Requests</td></tr></tbody></table>

## <mark style="color:red;">❊ PIV Distinguished Name Properties</mark>

The following list translates the shorthand distinguished names properties shown in OpenSSL config templates such as in the example below:

```properties
[ yubikey_dn ]
0.C                 = NA
1.ST                = NA
2.L                 = NA
3.O                 = Organization
4.OU                = Organization Unit
5.CN                = Your Common Name
6.emailAddress      = email@address.com
7.GN                = Your Given Name
8.title             = Cert Title
9.description       = Description about Cert
10.initials         = ABC
11.serialNumber     = 1234
```

<table><thead><tr><th width="89.33333333333331">ID</th><th width="170">Abbreviation</th><th>Name</th><th>Description</th></tr></thead><tbody><tr><td><strong>0</strong></td><td><mark style="color:red;"><strong><code>C</code></strong></mark></td><td>Country Name</td><td>The subject's country or region. This is an <a href="https://learn.microsoft.com/en-us/windows/win32/secgloss/x-gly"><em>X.500</em></a> two-character country/region code (for example US for United States or CA for Canada).</td></tr><tr><td>1</td><td><mark style="color:red;"><strong><code>ST</code></strong></mark></td><td>State Or Province Name</td><td>Full name of the subject's state or province (for example, California).</td></tr><tr><td>2</td><td><mark style="color:red;"><strong><code>L</code></strong></mark></td><td>Locality</td><td>Name of the subject's city.</td></tr><tr><td>3</td><td><mark style="color:red;"><strong><code>O</code></strong></mark></td><td>Organization Name</td><td>Legal name of the subject's organization.</td></tr><tr><td>4</td><td><mark style="color:red;"><strong><code>OU</code></strong></mark></td><td>Organizational Unit</td><td>Name of the subject's sub-organization or department.</td></tr><tr><td>5</td><td><mark style="color:red;"><strong><code>CN</code></strong></mark></td><td>Common Name</td><td>For user certificates, the person's full name.</td></tr><tr><td>6</td><td><mark style="color:red;"><strong><code>emailAddress</code></strong></mark></td><td>Email Address</td><td>Email address (for example, "someone@example.com").</td></tr><tr><td>7</td><td><mark style="color:red;"><strong><code>GN</code></strong></mark></td><td>Given Name</td><td>First name of the subject.</td></tr><tr><td>8</td><td><mark style="color:red;"><strong><code>title</code></strong></mark></td><td>Title</td><td>Title of individual who requested the certificate (optional).</td></tr><tr><td>9</td><td><mark style="color:red;"><strong><code>description</code></strong></mark></td><td>Description</td><td>Description of certificate</td></tr><tr><td>10</td><td><mark style="color:red;"><strong><code>initials</code></strong></mark></td><td>Initials</td><td>Initials of the subject (optional).</td></tr><tr><td>11</td><td><mark style="color:red;"><strong><code>serialNumber</code></strong></mark></td><td>serial number</td><td>Specify a serial number for your certificate or remove.</td></tr></tbody></table>

## <mark style="color:red;">❊ GPG File Types</mark>

The following list is associated to GPG keys.

<table><thead><tr><th width="166">File Type</th><th>Description</th></tr></thead><tbody><tr><td><mark style="color:red;"><strong><code>.gpg</code></strong></mark></td><td>gpg key -- binary</td></tr><tr><td><mark style="color:red;"><strong><code>.asc</code></strong></mark></td><td>gpg key -- armored</td></tr><tr><td><mark style="color:red;"><strong><code>.pub</code></strong></mark></td><td>openssh public key</td></tr><tr><td><mark style="color:red;"><strong><code>.sig</code></strong></mark></td><td>gpg signed document, binary format</td></tr></tbody></table>

## <mark style="color:red;">GPG Certificate Types</mark>

This list contains abbreviations you'll come across when you execute <mark style="color:red;">**`gpg --list-secret-keys`**</mark>

such as in the example:

```
ssc   rsa4096 2023-09-01 [SC]
      1523267825AB67256A25BBAD2567ABCDE2A46BAB
uid           [ultimate] YourName <youremail@outlook.com>
ssb   rsa4096 2023-01-01 [E]
sub   rsa4096 2023-01-01 [A]
```

<table><thead><tr><th width="170">Abbreviation</th><th>Description</th></tr></thead><tbody><tr><td><mark style="color:red;"><strong><code>sec</code></strong></mark></td><td>Secret Key</td></tr><tr><td><mark style="color:red;"><strong><code>ssb</code></strong></mark></td><td>Secret Subkey</td></tr><tr><td><mark style="color:red;"><strong><code>pub</code></strong></mark></td><td>Public Key</td></tr><tr><td><mark style="color:red;"><strong><code>sub</code></strong></mark></td><td>Public Subkey</td></tr><tr><td><mark style="color:red;"><strong><code>uid</code></strong></mark></td><td>User identification</td></tr></tbody></table>

## <mark style="color:red;">❊ GPG Key Capabilities</mark>

This list contains abbreviations you'll come across when you execute <mark style="color:red;">**`gpg --list-secret-keys`**</mark>

such as in the example:

```
pub   rsa4096 2023-01-01 [SC]
      12637B4335CB54B37C45AABC4F35ABCDE2A46BAB
uid           [ultimate] YourName <youremail@outlook.com>
sub   rsa4096 2023-01-01 [E]
sub   rsa4096 2023-01-01 [A]
```

<table><thead><tr><th width="170">Abbreviation</th><th>Description</th></tr></thead><tbody><tr><td><mark style="color:red;"><strong><code>A</code></strong></mark></td><td>Authenticate</td></tr><tr><td><mark style="color:red;"><strong><code>S</code></strong></mark></td><td>Sign</td></tr><tr><td><mark style="color:red;"><strong><code>C</code></strong></mark></td><td>Certify</td></tr><tr><td><mark style="color:red;"><strong><code>E</code></strong></mark></td><td>Encryption</td></tr></tbody></table>


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