diff --git a/book/source/06-signatures.md b/book/source/06-signatures.md
index 946d513..1832347 100644
--- a/book/source/06-signatures.md
+++ b/book/source/06-signatures.md
@@ -5,9 +5,9 @@ SPDX-License-Identifier: CC-BY-SA-4.0
 
 # OpenPGP Signatures
 
-Signatures are perhaps the single most central mechanism in OpenPGP. They act as the syntax that allows forming and interpreting rich statements about certificates and their components, as well as data.
+Signatures are a fundamental mechanism within OpenPGP. They provide the syntax for forming and interpreting comprehensive statements about certificates and their components, as well as for ensuring the integrity and authenticity of data.
 
-Without signatures, there would only be loose keys, impossible to associate with a certificate, or their owner. Signatures are the glue that allows for components (component keys and identity components) to be assembled into hierarchical certificates, and for messages to gain authenticity.
+Without signatures, keys would remain unassociated with any certificate or owner. Signatures are crucial for binding component keys and identity components into hierarchical certificates and for establishing the authenticity of messages.
 
 ## Terminology
 
diff --git a/book/source/diag/Fingerprint.png b/book/source/diag/Fingerprint.png
deleted file mode 100644
index dd54dc8..0000000
Binary files a/book/source/diag/Fingerprint.png and /dev/null differ
diff --git a/book/source/diag/Fingerprint.svg b/book/source/diag/Fingerprint.svg
deleted file mode 100644
index dbdacdf..0000000
--- a/book/source/diag/Fingerprint.svg
+++ /dev/null
@@ -1,304 +0,0 @@
-<?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<svg
-   viewBox="0 0 660.56769 379.09162"
-   version="1.1"
-   id="svg1"
-   sodipodi:docname="diag_library_draft.svg"
-   inkscape:version="1.3 (0e150ed6c4, 2023-07-21)"
-   width="660.56769"
-   height="379.09161"
-   xml:space="preserve"
-   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
-   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
-   xmlns="http://www.w3.org/2000/svg"
-   xmlns:svg="http://www.w3.org/2000/svg"><defs
-     id="defs1"><marker
-       style="overflow:visible"
-       id="Square"
-       refX="0"
-       refY="0"
-       orient="auto"
-       inkscape:stockid="Square"
-       markerWidth="1"
-       markerHeight="1"
-       viewBox="0 0 1 1"
-       inkscape:isstock="true"
-       inkscape:collect="always"
-       preserveAspectRatio="xMidYMid"><path
-         transform="scale(0.5)"
-         style="fill:context-stroke;fill-rule:evenodd;stroke:none"
-         d="M -5,-5 V 5 H 5 V -5 Z"
-         id="path18" /></marker><linearGradient
-       id="swatch251"
-       inkscape:swatch="solid"><stop
-         style="stop-color:#195962;stop-opacity:1;"
-         offset="0"
-         id="stop251" /></linearGradient><inkscape:path-effect
-       effect="fillet_chamfer"
-       id="path-effect66-9"
-       is_visible="true"
-       lpeversion="1"
-       nodesatellites_param="F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1"
-       radius="0"
-       unit="px"
-       method="auto"
-       mode="F"
-       chamfer_steps="1"
-       flexible="false"
-       use_knot_distance="true"
-       apply_no_radius="true"
-       apply_with_radius="true"
-       only_selected="false"
-       hide_knots="false" /><inkscape:path-effect
-       effect="fillet_chamfer"
-       id="path-effect35-9-9"
-       is_visible="true"
-       lpeversion="1"
-       nodesatellites_param="F,0,1,1,0,18.14255,0,1 @ F,0,1,1,0,18.14255,0,1 @ F,0,1,1,0,18.14255,0,1 @ F,0,1,1,0,18.14255,0,1"
-       radius="0"
-       unit="px"
-       method="auto"
-       mode="F"
-       chamfer_steps="1"
-       flexible="false"
-       use_knot_distance="true"
-       apply_no_radius="true"
-       apply_with_radius="true"
-       only_selected="false"
-       hide_knots="false" /><inkscape:path-effect
-       effect="fillet_chamfer"
-       id="path-effect32-1-8"
-       is_visible="true"
-       lpeversion="1"
-       nodesatellites_param="F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 | F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 | F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1 @ F,0,0,1,0,0,0,1"
-       radius="0"
-       unit="px"
-       method="auto"
-       mode="F"
-       chamfer_steps="1"
-       flexible="false"
-       use_knot_distance="true"
-       apply_no_radius="true"
-       apply_with_radius="true"
-       only_selected="false"
-       hide_knots="false" /><filter
-       style="color-interpolation-filters:sRGB"
-       inkscape:label="Drop Shadow"
-       id="filter90"
-       x="-0.02018661"
-       y="-0.031382764"
-       width="1.0434854"
-       height="1.070755"><feFlood
-         result="flood"
-         in="SourceGraphic"
-         flood-opacity="0.796078"
-         flood-color="rgb(62,67,73)"
-         id="feFlood89" /><feGaussianBlur
-         result="blur"
-         in="SourceGraphic"
-         stdDeviation="2.132 0"
-         id="feGaussianBlur89" /><feOffset
-         result="offset"
-         in="blur"
-         dx="1.000000"
-         dy="1.000000"
-         id="feOffset89" /><feComposite
-         result="comp1"
-         operator="in"
-         in="flood"
-         in2="offset"
-         id="feComposite89" /><feComposite
-         result="fbSourceGraphic"
-         operator="over"
-         in="SourceGraphic"
-         in2="comp1"
-         id="feComposite90" /><feColorMatrix
-         result="fbSourceGraphicAlpha"
-         in="fbSourceGraphic"
-         values="0 0 0 -1 0 0 0 0 -1 0 0 0 0 -1 0 0 0 0 1 0"
-         id="feColorMatrix90" /><feFlood
-         id="feFlood90"
-         result="flood"
-         in="fbSourceGraphic"
-         flood-opacity="0.796078"
-         flood-color="rgb(62,67,73)" /><feGaussianBlur
-         id="feGaussianBlur90"
-         result="blur"
-         in="fbSourceGraphic"
-         stdDeviation="3.000000" /><feOffset
-         id="feOffset90"
-         result="offset"
-         in="blur"
-         dx="1.000000"
-         dy="1.000000" /><feComposite
-         id="feComposite91"
-         result="comp1"
-         operator="in"
-         in="flood"
-         in2="offset" /><feComposite
-         id="feComposite92"
-         result="comp2"
-         operator="over"
-         in="fbSourceGraphic"
-         in2="comp1" /></filter></defs><sodipodi:namedview
-     id="namedview1"
-     pagecolor="#ffffff"
-     bordercolor="#000000"
-     borderopacity="0.25"
-     inkscape:showpageshadow="2"
-     inkscape:pageopacity="0.0"
-     inkscape:pagecheckerboard="0"
-     inkscape:deskcolor="#d1d1d1"
-     inkscape:lockguides="false"
-     inkscape:zoom="1"
-     inkscape:cx="1453.5"
-     inkscape:cy="730.5"
-     inkscape:window-width="2560"
-     inkscape:window-height="1371"
-     inkscape:window-x="0"
-     inkscape:window-y="305"
-     inkscape:window-maximized="1"
-     inkscape:current-layer="g40"
-     showgrid="false"
-     inkscape:export-bgcolor="#ffffff00"
-     showguides="false"><inkscape:page
-       x="2.5476957e-08"
-       y="4.1418102e-06"
-       width="660.56769"
-       height="379.09161"
-       id="page66"
-       margin="0"
-       bleed="0" /></sodipodi:namedview><!--! Font Awesome Pro 6.4.2 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license (Commercial License) Copyright 2023 Fonticons, Inc. --><g
-     inkscape:groupmode="layer"
-     id="layer5"
-     inkscape:label="Chapter 4"
-     inkscape:highlight-color="#baa600"
-     transform="translate(-811.81226,-1223.9908)"><g
-       inkscape:groupmode="layer"
-       id="layer7"
-       inkscape:label="Component Key"
-       transform="translate(11.236271,-4.7700578)"
-       style="display:inline"><path
-         style="opacity:1;mix-blend-mode:normal;fill:#ffffff;fill-opacity:1;stroke:#e6e6e6;stroke-width:1.312;stroke-linecap:butt;stroke-linejoin:miter;stroke-dasharray:none;stroke-dashoffset:0;stroke-opacity:1;paint-order:fill markers stroke;filter:url(#filter90)"
-         id="rect65-3"
-         width="642.6438"
-         height="250.32849"
-         x="825.70776"
-         y="875.02576"
-         transform="matrix(0.90039676,0,0,1.2175633,97.177615,208.49295)"
-         inkscape:path-effect="#path-effect66-9"
-         sodipodi:type="rect"
-         d="m 851.7972,875.02576 h 590.4649 c 14.4536,0 26.0895,8.60482 26.0895,19.29332 v 211.74182 c 0,10.6885 -11.6359,19.2933 -26.0895,19.2933 H 851.7972 c -14.45355,0 -26.08944,-8.6048 -26.08944,-19.2933 V 894.31908 c 0,-10.6885 11.63589,-19.29332 26.08944,-19.29332 z"
-         ry="19.293327"
-         rx="26.089437" /><g
-         id="g11-8-3"
-         transform="matrix(0.86376245,0,0,0.86376245,109.50803,1110.3706)"
-         inkscape:label="Diagramm Header"
-         style="display:inline;fill:#61a78d;fill-opacity:1"><rect
-           style="font-variation-settings:'wght' 700;fill:#195962;stroke-width:2.471;stroke-linecap:round;stroke-linejoin:round;paint-order:markers fill stroke"
-           id="rect1-9-8"
-           width="329.94476"
-           height="57.886284"
-           x="914.89185"
-           y="156.37508" /><g
-           id="g4-7-0"
-           transform="translate(-11.145477,39.927363)"><rect
-             style="font-variation-settings:'wght' 700;fill:#e6e6e6;fill-opacity:1;stroke-width:2.47329;stroke-linecap:round;stroke-linejoin:round;paint-order:markers fill stroke"
-             id="rect1-3-7-5"
-             width="330.55685"
-             height="57.886284"
-             x="917.30688"
-             y="126.45267" /><text
-             xml:space="preserve"
-             style="font-style:normal;font-variant:normal;font-weight:600;font-stretch:normal;font-size:24px;font-family:Montserrat;-inkscape-font-specification:'Montserrat, Semi-Bold';font-variant-ligatures:normal;font-variant-caps:normal;font-variant-numeric:normal;font-variant-east-asian:normal;white-space:pre;inline-size:345.106;display:inline;fill:#3e4349;fill-opacity:1;stroke-width:3.5;stroke-linecap:round;stroke-linejoin:round;paint-order:markers fill stroke"
-             x="954.24536"
-             y="158.38867"
-             id="text1-6-6"
-             transform="matrix(0.85813569,0,0,0.85813569,117.98976,13.088921)"><tspan
-               x="954.24536"
-               y="158.38867"
-               id="tspan1">Fingerprint of an OpenPGP &#10;</tspan><tspan
-               x="954.24536"
-               y="188.38867"
-               id="tspan2">component key </tspan></text></g></g><g
-         id="g41-8"
-         style="display:inline"
-         inkscape:label="Subkey encr"
-         transform="translate(144.65109,1015.3407)"><path
-           id="rect11-2-2"
-           d="m 884.2432,192.95468 h 359.0109 a 18.14255,18.14255 45 0 1 18.1425,18.14255 v 126.63435 a 18.14255,18.14255 135 0 1 -18.1425,18.14255 H 884.2432 A 18.14255,18.14255 45 0 1 866.10065,337.73158 V 211.09723 a 18.14255,18.14255 135 0 1 18.14255,-18.14255 z"
-           style="font-variation-settings:'wght' 500;fill:none;fill-opacity:0.1;stroke:#195962;stroke-width:4.39384;stroke-linecap:round;stroke-linejoin:round;stroke-dasharray:none;stroke-opacity:1;paint-order:markers fill stroke"
-           inkscape:path-effect="#path-effect35-9-9"
-           inkscape:original-d="M 866.10065,192.95468 H 1261.3966 V 355.87413 H 866.10065 Z"
-           transform="matrix(0.94985532,0,0,0.73417064,31.221087,187.24009)" /><text
-           xml:space="preserve"
-           style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:22.2565px;font-family:Sans;-inkscape-font-specification:'Sans, @wght=500';font-variant-ligatures:normal;font-variant-caps:normal;font-variant-numeric:normal;font-variant-east-asian:normal;font-variation-settings:'wght' 500;text-align:start;text-anchor:start;fill:#3e4349;fill-opacity:1;stroke:none;stroke-width:3.65147;stroke-linecap:round;stroke-linejoin:round;stroke-opacity:1;paint-order:markers fill stroke"
-           x="879.95685"
-           y="407.40775"
-           id="text11-6-9"
-           transform="scale(0.98944428,1.0106683)"><tspan
-             sodipodi:role="line"
-             id="tspan11-94-9"
-             x="879.95685"
-             y="407.40775"
-             style="font-style:normal;font-variant:normal;font-weight:500;font-stretch:normal;font-size:22.2565px;font-family:Montserrat;-inkscape-font-specification:'Montserrat Medium';text-align:start;text-anchor:start;stroke-width:3.65147">- key creation time</tspan></text><path
-           id="path2-1-6"
-           style="display:inline;fill:none;stroke:#006961;stroke-width:10.4431;stroke-linecap:round;stroke-dasharray:none;stroke-opacity:1"
-           d="m 156.30312,759.25868 c -9.78054,19.91382 -30.12868,33.02384 -53.81237,33.02384 -33.173715,0 -60.066326,-26.89261 -60.066326,-60.06633 0,-33.17372 26.892611,-60.06633 60.066326,-60.06633 23.31181,0 43.58824,15.15712 53.54415,34.5646 m -9.14624,1.20213 h 4.97796 c 10.89491,0.20296 25.86265,0 38.79397,0 l 11.43353,7.63836 14.59897,-7.63836 14.59896,7.3422 h 10.87817 l 11.54761,-7.3422 17.66083,7.3422 16.34856,-7.34219 22,25.45886 -22,25.45887 h -135.8606 -4.97796 M 89.058073,732.21619 c -4e-6,6.98969 -5.666271,12.65596 -12.655965,12.65596 -6.989695,0 -12.655963,-5.66627 -12.655967,-12.65596 -2e-6,-6.9897 5.666268,-12.65597 12.655967,-12.65597 6.989698,0 12.655967,5.66627 12.655965,12.65597 z"
-           inkscape:label="Publickey ((Asym))"
-           sodipodi:nodetypes="cssscccccccccccccccsssss"
-           transform="matrix(0.32619502,0,0,-0.33319205,1106.4974,649.79131)"
-           inkscape:path-effect="#path-effect32-1-8"
-           inkscape:original-d="m 156.30312,759.25868 c -9.78054,19.91382 -30.12868,33.02384 -53.81237,33.02384 -33.173715,0 -60.066326,-26.89261 -60.066326,-60.06633 0,-33.17372 26.892611,-60.06633 60.066326,-60.06633 23.31181,0 43.58824,15.15712 53.54415,34.5646 m -9.14624,1.20213 h 4.97796 c 10.89491,0.20296 25.86265,0 38.79397,0 l 11.43353,7.63836 14.59897,-7.63836 14.59896,7.3422 h 10.87817 l 11.54761,-7.3422 17.66083,7.3422 16.34856,-7.34219 22,25.45886 -22,25.45887 h -135.8606 -4.97796 M 89.058073,732.21619 c -4e-6,6.98969 -5.666271,12.65596 -12.655965,12.65596 -6.989695,0 -12.655963,-5.66627 -12.655967,-12.65596 -2e-6,-6.9897 5.666268,-12.65597 12.655967,-12.65597 6.989698,0 12.655967,5.66627 12.655965,12.65597 z" /><text
-           xml:space="preserve"
-           style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:22.2565px;font-family:Sans;-inkscape-font-specification:'Sans, @wght=500';font-variant-ligatures:normal;font-variant-caps:normal;font-variant-numeric:normal;font-variant-east-asian:normal;font-variation-settings:'wght' 500;text-align:start;text-anchor:start;opacity:1;fill:#3e4349;fill-opacity:1;stroke:none;stroke-width:3.65147;stroke-linecap:round;stroke-linejoin:round;stroke-opacity:1;paint-order:markers fill stroke"
-           x="880.12274"
-           y="357.29468"
-           id="text11-2-8-02"
-           transform="scale(0.98944428,1.0106683)"><tspan
-             sodipodi:role="line"
-             id="tspan11-9-0-7"
-             x="880.12274"
-             y="357.29468"
-             style="font-style:normal;font-variant:normal;font-weight:500;font-stretch:normal;font-size:22.2565px;font-family:Montserrat;-inkscape-font-specification:'Montserrat Medium';text-align:start;text-anchor:start;stroke-width:3.65147">Component Key</tspan></text></g><g
-         id="g67"
-         transform="translate(142.42627,1018.1906)"
-         style="display:inline;stroke-width:1.7;stroke-dasharray:none"><rect
-           style="fill:#baa600;fill-opacity:0.25;stroke:#baa600;stroke-width:1.4;stroke-linecap:butt;stroke-linejoin:miter;stroke-dasharray:2.8, 2.8;stroke-dashoffset:0;stroke-opacity:1;paint-order:fill markers stroke"
-           id="rect66"
-           width="378.45499"
-           height="52.826336"
-           x="855.52289"
-           y="454.69138" /><text
-           xml:space="preserve"
-           style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:21.3333px;line-height:17.9px;font-family:Sans;-inkscape-font-specification:'Sans, @wght=500';font-variant-ligatures:normal;font-variant-caps:normal;font-variant-numeric:normal;font-variant-east-asian:normal;font-variation-settings:'wght' 500;text-align:start;text-anchor:start;white-space:pre;inline-size:393.624;display:inline;opacity:1;fill:#3e4349;fill-opacity:1;stroke:none;stroke-width:1.7786;stroke-linecap:round;stroke-linejoin:round;stroke-dasharray:none;stroke-opacity:1;paint-order:markers fill stroke"
-           x="562.8764"
-           y="408.97891"
-           id="text11-3-4-3"
-           transform="matrix(0.95580583,0,0,0.95580583,326.86618,86.500043)"
-           inkscape:label="fingerprint sk encr"><tspan
-             x="562.8764"
-             y="408.97891"
-             id="tspan4"><tspan
-   style="font-size:16px;font-family:Monospace;-inkscape-font-specification:'Monospace, Normal'"
-   id="tspan3">C0A5 8384 A438 E5A1 4F73 7124 26A4 D45D</tspan> </tspan><tspan
-             x="562.8764"
-             y="428.39824"
-             id="tspan6"><tspan
-               style="font-size:16px;font-family:Monospace;-inkscape-font-specification:'Monospace, Normal'"
-               id="tspan5">BAEE F4A3 9E6B 30B0 9D55 13F9 78AC CA94</tspan></tspan></text><text
-           xml:space="preserve"
-           style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:18.6667px;font-family:Sans;-inkscape-font-specification:'Sans, @wght=500';font-variant-ligatures:normal;font-variant-caps:normal;font-variant-numeric:normal;font-variant-east-asian:normal;font-variation-settings:'wght' 500;text-align:start;text-anchor:start;display:inline;fill:#3e4349;fill-opacity:1;stroke:none;stroke-width:1.7;stroke-linecap:round;stroke-linejoin:round;stroke-dasharray:none;stroke-opacity:1;paint-order:markers fill stroke"
-           x="740.55432"
-           y="476.66418"
-           id="text11-2-8-02-9"
-           transform="scale(0.98944431,1.0106683)"><tspan
-             sodipodi:role="line"
-             id="tspan11-9-0-7-1"
-             x="740.55432"
-             y="476.66418"
-             style="font-style:normal;font-variant:normal;font-weight:500;font-stretch:normal;font-size:18.6667px;font-family:Montserrat;-inkscape-font-specification:'Montserrat Medium';text-align:start;text-anchor:start;stroke-width:1.7;stroke-dasharray:none">Fingerprint</tspan></text><path
-           style="opacity:1;fill:none;fill-opacity:1;stroke:#baa600;stroke-width:1.4;stroke-linecap:butt;stroke-linejoin:miter;stroke-dasharray:2.8, 2.8;stroke-dashoffset:0;stroke-opacity:1;marker-start:url(#Square);paint-order:fill markers stroke"
-           d="m 853.59098,505.62944 -78.85694,0.0298 -0.27607,-16.40163"
-           id="path252"
-           sodipodi:nodetypes="ccc" /></g></g></g></svg>