private-wrap : Export pubKey serialization

src/private-wrap.ts

@@ -34,8 +34,7 @@ export class PrivateWrap {
 
   public async toString(): Promise<string> {
     log.trace('toString')
-    const pubkey_spki = await crypto.subtle.exportKey('spki', this.pubkey)
-    const pubkey = a2b64(new Uint8Array(pubkey_spki))
+    const pubkey = await PrivateWrap.publicKey_toString(this.pubkey)
     const box = this.box.toString()
     return `${pubkey}.${box}`
   }
@@ -45,13 +44,25 @@ export class PrivateWrap {
     const parts = data.split('.', 2)
     if (parts.length !== 2) return null
 
-    const pubkey_str = b642a(parts[0])
-    if (pubkey_str.is_err()) return null
-    const pubkey = await crypto.subtle.importKey('spki', pubkey_str.unwrap(), algorithm, true, [])
-
+    const pubkey = await this.publicKey_fromString(parts[0])
+    if (pubkey === null) return null
     const box = SecretWrap.fromString(parts[1])
     if (box === null) return null
 
     return new PrivateWrap(box, pubkey)
   }
+
+  public static async publicKey_toString(publicKey: CryptoKey): Promise<string> {
+    const pubkey_spki = await crypto.subtle.exportKey('spki', publicKey)
+    return a2b64(new Uint8Array(pubkey_spki))
+  }
+  public static async publicKey_fromString(data: string): Promise<CryptoKey | null> {
+    const pubkey_str = b642a(data)
+    if (pubkey_str.is_err()) return null
+    try {
+      return crypto.subtle.importKey('spki', pubkey_str.unwrap(), algorithm, true, [])
+    } catch(e) {
+      return null
+    }
+  }
 }