Implement secret-wrap

2024-06-06 01:50:20 +02:00
parent 0d82d303d9
commit 1f8ff50fd3
1 changed files with 83 additions and 0 deletions
@@ -0,0 +1,83 @@
+import logger from 'log'
+import {a2b64, b642a} from 'misc'
+
+const log = logger('crypto:secret-wrap')
+
+export class SecretWrap {
+    constructor(
+        private readonly cipher: Uint8Array,
+        private readonly algorithm: KeyAlgorithm,
+        private readonly usages: KeyUsage[],
+        private readonly type: "raw" | "pkcs8",
+        private readonly iv: Uint8Array,
+    ) {}
+
+    public static gen_key() : Promise<CryptoKey> {
+        log.trace("generate key")
+        return crypto.subtle.generateKey(
+            {
+                name: "AES-GCM",
+                length: 256,
+            },
+            true,
+            ["wrapKey", "unwrapKey"],
+        )
+    }
+
+    private static format(type: KeyType) : "raw" | "pkcs8" {
+        switch (type) {
+            case "private": return "pkcs8"
+            case "secret": return "raw"
+            default: throw "Don't wrap public keys please..."
+        }
+    }
+
+    public static async encrypt(data: CryptoKey, key: CryptoKey) : Promise<SecretWrap> {
+        log.trace("encrypt")
+        const format = this.format(data.type)
+        const iv = crypto.getRandomValues(new Uint8Array(12))
+        const box = await crypto.subtle.wrapKey(
+            format,
+            data,
+            key,
+            {
+                name: "AES-GCM",
+                iv,
+            },
+        )
+        return new SecretWrap(new Uint8Array(box), data.algorithm, data.usages, format, iv)
+    }
+    public async decrypt(key: CryptoKey) : Promise<CryptoKey> {
+        log.trace("decrypt")
+        return crypto.subtle.unwrapKey(
+            this.type,
+            this.cipher,
+            key,
+            {
+                name: "AES-GCM",
+                iv: this.iv,
+            },
+            this.algorithm,
+            true,
+            this.usages
+        )
+    }
+
+    public toString() : string {
+        log.trace("toString")
+        return JSON.stringify({
+            cipher: a2b64(this.cipher),
+            iv: a2b64(this.iv),
+            algorithm: this.algorithm,
+            usages: this.usages,
+            type: this.type,
+        })
+    }
+    public static fromString(data: string) : SecretWrap {
+        log.trace("fromString")
+        const obj = JSON.parse(data)
+        const cipher = b642a(obj.cipher).expect("Failed to decode cipher")
+        const iv = b642a(obj.iv).expect("Failed to decode IV")
+        return new SecretWrap(cipher, obj.algorithm, obj.usages, obj.type, iv)
+    }
+}