vk generation

Author: jialinli98

ethereum/oracles/src/noir/circuit/README.md

@@ -19,8 +19,9 @@ Unfortunately `nargo` does not generate any of the recursion artifacts. Noir tea
 - Compiled artifact - `target/${name}.json`
   - generated from code using `nargo compile --package ${name}`
   - It's a JSON that contains [`base64`](https://en.wikipedia.org/wiki/Base64) encoded bytecode under the `.bytecode` key
+  - The bytecode is gzip-compressed before base64 encoding
 - Acir bytecode
-  - generated from **compiled artifact** by taking the bytecode and decoding it as `base64`, as **bb** expects it in plain binary form. We use a temp file for it as it's fast to generate and we only use it during **VK** generation
+  - generated from **compiled artifact** by decoding the bytecode from `base64` and decompressing it (gzipped), as **bb** expects it in plain binary form. We use a temp file for it as it's fast to generate and we only use it during **VK** generation
 - VK - `target/${name}.vk.bin`
   - verification key is generated from **acir bytecode** by running:
     - `./bb write_vk -b ${acirPath} -o ${vkPath}`

ethereum/oracles/src/noir/circuit/vk.ts

@@ -1,10 +1,18 @@
 import { readObject, withTempFile } from '../../util/file.js';
 import { writeFile } from 'fs/promises';
+import { gunzipSync } from 'zlib';
 import { Barretenberg } from './barretenberg.js';
 
 export async function generateVk(bytecode: string, vkPath: string, vkAsFieldsPath: string): Promise<void> {
   return await withTempFile(async (acirPath) => {
-    await writeFile(acirPath, Buffer.from(bytecode, 'base64'));
+    // Decode base64 bytecode
+    const compressedBytecode = Buffer.from(bytecode, 'base64');
+    // Decompress if gzipped (Nargo compresses bytecode before base64 encoding)
+    const decompressedBytecode = compressedBytecode[0] === 0x1f && compressedBytecode[1] === 0x8b
+      ? gunzipSync(compressedBytecode)
+      : compressedBytecode;
+
+    await writeFile(acirPath, decompressedBytecode);
 
     const barretenberg = await Barretenberg.create();
     await barretenberg.writeVK(acirPath, vkPath);