From cb25f21c44d50f3e49e2b7cececbf8334cc620d3 Mon Sep 17 00:00:00 2001
From: Alex Blank <alexblank@fastmail.com>
Date: Fri, 22 May 2026 21:33:21 +0000
Subject: [PATCH] feat: add SSH key signing and verification UI

---
 apps/web/src/api/ssh_keys.ts    |  27 ++++++
 apps/web/src/pages/ssh-keys.tsx | 149 +++++++++++++++++++++++++++++++-
 2 files changed, 175 insertions(+), 1 deletion(-)

diff --git a/apps/web/src/api/ssh_keys.ts b/apps/web/src/api/ssh_keys.ts
index 84061d7..46aa0e5 100644
--- a/apps/web/src/api/ssh_keys.ts
+++ b/apps/web/src/api/ssh_keys.ts
@@ -24,3 +24,30 @@ export async function createSSHKey(data: SSHKeyCreate): Promise<SSHKey> {
 export async function deleteSSHKey(keyId: string): Promise<void> {
   await apiClient.delete(`/ssh-keys/${keyId}`);
 }
+
+export interface SignPayloadRequest {
+  payload: string;
+}
+
+export interface SignatureResponse {
+  signature: string;
+}
+
+export interface VerifySignatureRequest {
+  payload: string;
+  signature: string;
+}
+
+export interface VerifySignatureResponse {
+  valid: boolean;
+}
+
+export async function signPayload(keyId: string, data: SignPayloadRequest): Promise<SignatureResponse> {
+  const response = await apiClient.post<SignatureResponse>(`/ssh-keys/${keyId}/sign`, data);
+  return response.data;
+}
+
+export async function verifySignature(keyId: string, data: VerifySignatureRequest): Promise<VerifySignatureResponse> {
+  const response = await apiClient.post<VerifySignatureResponse>(`/ssh-keys/${keyId}/verify`, data);
+  return response.data;
+}
diff --git a/apps/web/src/pages/ssh-keys.tsx b/apps/web/src/pages/ssh-keys.tsx
index 264d317..60fc57f 100644
--- a/apps/web/src/pages/ssh-keys.tsx
+++ b/apps/web/src/pages/ssh-keys.tsx
@@ -1,6 +1,6 @@
 import { useEffect, useState } from "react";
 import { useNavigate } from "react-router-dom";
-import { createSSHKey, deleteSSHKey, listSSHKeys, type SSHKey } from "../api/ssh_keys";
+import { createSSHKey, deleteSSHKey, listSSHKeys, signPayload, verifySignature, type SSHKey } from "../api/ssh_keys";
 import { Icon } from "../components/icon";
 
 export const SSHKeysPage = () => {
@@ -10,6 +10,13 @@ export const SSHKeysPage = () => {
   const [error, setError] = useState<string | null>(null);
   const [newKeyName, setNewKeyName] = useState("");
   const [generating, setGenerating] = useState(false);
+  const [signPayloads, setSignPayloads] = useState<Record<string, string>>({});
+  const [signatures, setSignatures] = useState<Record<string, string>>({});
+  const [signing, setSigning] = useState<Record<string, boolean>>({});
+  const [verifyPayloads, setVerifyPayloads] = useState<Record<string, string>>({});
+  const [verifySignatures, setVerifySignatures] = useState<Record<string, string>>({});
+  const [verifyResults, setVerifyResults] = useState<Record<string, boolean | null>>({});
+  const [verifying, setVerifying] = useState<Record<string, boolean>>({});
 
   useEffect(() => {
     loadKeys();
@@ -59,6 +66,42 @@ export const SSHKeysPage = () => {
     navigator.clipboard.writeText(text);
   }
 
+  async function handleSign(keyId: string) {
+    const payload = signPayloads[keyId];
+    if (!payload?.trim()) return;
+
+    try {
+      setSigning((prev) => ({ ...prev, [keyId]: true }));
+      const result = await signPayload(keyId, { payload: payload.trim() });
+      setSignatures((prev) => ({ ...prev, [keyId]: result.signature }));
+      setError(null);
+    } catch {
+      setError("Failed to sign payload");
+    } finally {
+      setSigning((prev) => ({ ...prev, [keyId]: false }));
+    }
+  }
+
+  async function handleVerify(keyId: string) {
+    const payload = verifyPayloads[keyId];
+    const signature = verifySignatures[keyId];
+    if (!payload?.trim() || !signature?.trim()) return;
+
+    try {
+      setVerifying((prev) => ({ ...prev, [keyId]: true }));
+      const result = await verifySignature(keyId, {
+        payload: payload.trim(),
+        signature: signature.trim(),
+      });
+      setVerifyResults((prev) => ({ ...prev, [keyId]: result.valid }));
+      setError(null);
+    } catch {
+      setError("Failed to verify signature");
+    } finally {
+      setVerifying((prev) => ({ ...prev, [keyId]: false }));
+    }
+  }
+
   if (loading) return <div>Loading...</div>;
 
   return (
@@ -133,6 +176,110 @@ export const SSHKeysPage = () => {
                   Copy Full Key
                 </button>
               </div>
+
+              <div className="key-signing">
+                <h4>Sign Payload</h4>
+                <div className="form-group">
+                  <textarea
+                    value={signPayloads[key.id] || ""}
+                    onChange={(e) =>
+                      setSignPayloads((prev) => ({ ...prev, [key.id]: e.target.value }))
+                    }
+                    placeholder="Enter payload to sign..."
+                    rows={3}
+                  />
+                </div>
+                <button
+                  onClick={() => handleSign(key.id)}
+                  disabled={signing[key.id] || !signPayloads[key.id]?.trim()}
+                  className="primary-button"
+                >
+                  {signing[key.id] ? (
+                    <>
+                      <Icon name="loading" size="sm" />
+                      Signing...
+                    </>
+                  ) : (
+                    <>
+                      <Icon name="edit" size="sm" />
+                      Sign
+                    </>
+                  )}
+                </button>
+                {signatures[key.id] && (
+                  <div className="signature-result">
+                    <label>Signature (base64):</label>
+                    <code>{signatures[key.id]}</code>
+                    <button
+                      onClick={() => copyToClipboard(signatures[key.id])}
+                      className="secondary-button"
+                    >
+                      <Icon name="copy" size="sm" />
+                      Copy Signature
+                    </button>
+                  </div>
+                )}
+              </div>
+
+              <div className="key-verification">
+                <h4>Verify Signature</h4>
+                <div className="form-group">
+                  <textarea
+                    value={verifyPayloads[key.id] || ""}
+                    onChange={(e) =>
+                      setVerifyPayloads((prev) => ({ ...prev, [key.id]: e.target.value }))
+                    }
+                    placeholder="Enter payload..."
+                    rows={2}
+                  />
+                </div>
+                <div className="form-group">
+                  <textarea
+                    value={verifySignatures[key.id] || ""}
+                    onChange={(e) =>
+                      setVerifySignatures((prev) => ({ ...prev, [key.id]: e.target.value }))
+                    }
+                    placeholder="Enter base64 signature..."
+                    rows={2}
+                  />
+                </div>
+                <button
+                  onClick={() => handleVerify(key.id)}
+                  disabled={
+                    verifying[key.id] ||
+                    !verifyPayloads[key.id]?.trim() ||
+                    !verifySignatures[key.id]?.trim()
+                  }
+                  className="primary-button"
+                >
+                  {verifying[key.id] ? (
+                    <>
+                      <Icon name="loading" size="sm" />
+                      Verifying...
+                    </>
+                  ) : (
+                    <>
+                      <Icon name="success" size="sm" />
+                      Verify
+                    </>
+                  )}
+                </button>
+                {verifyResults[key.id] !== undefined && verifyResults[key.id] !== null && (
+                  <div className={`verify-result ${verifyResults[key.id] ? "valid" : "invalid"}`}>
+                    {verifyResults[key.id] ? (
+                      <>
+                        <Icon name="success" size="sm" />
+                        Signature is valid
+                      </>
+                    ) : (
+                      <>
+                        <Icon name="error" size="sm" />
+                        Signature is invalid
+                      </>
+                    )}
+                  </div>
+                )}
+              </div>
             </div>
           ))
         )}