diff --git a/openid-zkp-auth/js/circuitutils.js b/openid-zkp-auth/js/circuitutils.js
index 2c3e76433e..2f90f67dc6 100644
--- a/openid-zkp-auth/js/circuitutils.js
+++ b/openid-zkp-auth/js/circuitutils.js
@@ -3,6 +3,7 @@ const {toBigIntBE, toBufferBE} = require('bigint-buffer');
 
 const utils = require('./utils');
 const jwtutils = require('./jwtutils');
+const compressutils = require('./compressutils');
 
 const constants = require('./constants');
 const claimsToReveal = constants.claimsToReveal;
@@ -219,7 +220,7 @@ async function genJwtProofUAInputs(
     ], poseidon);
 
     const auxiliary_inputs = {
-        "masked_content": masked_content,
+        "masked_content": compressutils.compressVector(masked_content),
         "jwt_sha2_hash": jwt_sha2_hash.map(e => e.toString()),
         "payload_start_index": inputs.payload_start_index,
         "payload_len": inputs.payload_len,
diff --git a/openid-zkp-auth/js/compressutils.js b/openid-zkp-auth/js/compressutils.js
new file mode 100644
index 0000000000..8ea9df825e
--- /dev/null
+++ b/openid-zkp-auth/js/compressutils.js
@@ -0,0 +1,51 @@
+const compressVector = (vector, targetNumber) => {
+    let otherNumbers = [];
+    let targetNumberIndices = [];
+    let inRun = false;
+    let startIdx = 0;
+    let targetCount = 0;
+
+    for (let i = 0; i < vector.length; i++) {
+        if (vector[i] === targetNumber) {
+            if (!inRun) {
+                inRun = true;
+                startIdx = i;
+            }
+            targetCount++;
+        } else {
+            if (inRun) {
+                inRun = false;
+                targetNumberIndices.push([startIdx, i - 1]);
+            }
+            otherNumbers.push(vector[i]);
+        }
+    }
+
+    if (inRun) {
+        targetNumberIndices.push([startIdx, vector.length - 1]);
+    }
+
+    return [
+        otherNumbers,
+        targetNumberIndices
+    ];
+};
+
+const decompressVector = (compressedVector, targetNumber) => {
+    let decompressedVector = [...compressedVector[0]];
+    let offset = 0;
+    for (let i = 0; i < compressedVector[1].length; i++) {
+        let start = compressedVector[1][i][0] + offset;
+        let end = compressedVector[1][i][1] + offset;
+        let length = end - start + 1;
+        decompressedVector.splice(start, 0, ...Array(length).fill(targetNumber));
+        start += length;
+        offset += end - start + 1;
+    }
+    return decompressedVector;
+};
+
+module.exports = {
+    compressVector: compressVector,
+    decompressVector: decompressVector
+}
\ No newline at end of file
diff --git a/openid-zkp-auth/js/verify.js b/openid-zkp-auth/js/verify.js
index 35f16ef60a..0e61412ab3 100644
--- a/openid-zkp-auth/js/verify.js
+++ b/openid-zkp-auth/js/verify.js
@@ -1,6 +1,7 @@
 const jwt = require("jsonwebtoken");
 const jwkToPem = require("jwk-to-pem");
 
+const compressutils = require("./compressutils");
 const jwtutils = require("./jwtutils");
 const { toBigIntBE } = require("bigint-buffer");
 
@@ -40,6 +41,9 @@ function checkMaskedContent (
     expected_payload_len,
     expected_length
 ){
+    // Decompress masked_content
+    masked_content = compressutils.decompressVector(masked_content, 61);
+
     if (masked_content.length != expected_length) throw new Error("Invalid length");
     if (num_sha2_blocks * 64 > masked_content.length) throw new Error("Invalid last block");
 
diff --git a/openid-zkp-auth/test/main.circom.test.js b/openid-zkp-auth/test/main.circom.test.js
index e8a033a5fc..b7612161d3 100644
--- a/openid-zkp-auth/test/main.circom.test.js
+++ b/openid-zkp-auth/test/main.circom.test.js
@@ -11,6 +11,7 @@ const utils = require("../js/utils");
 const verify = require('../js/verify');
 
 const testutils = require("./testutils");
+const compressutils = require("../js/compressutils");
 
 async function genCircuit(
     maxContentLen = constants.maxContentLen,
@@ -53,9 +54,8 @@ async function genProof(
     const w = await circuit.calculateWitness(inputs, true);
     await circuit.checkConstraints(w);
 
-    const masked_content = utils.applyMask(inputs["content"], inputs["mask"]);
     verify.checkMaskedContent(
-        masked_content,
+        auxiliary_inputs["masked_content"],
         inputs["num_sha2_blocks"],
         inputs["payload_start_index"],
         inputs["payload_len"],