diff --git a/migrations/20260209061552_encrypt_auth_tokens_with_iv.js b/migrations/20260209061552_encrypt_auth_tokens_with_iv.js
new file mode 100644
index 000000000..81203a3b2
--- /dev/null
+++ b/migrations/20260209061552_encrypt_auth_tokens_with_iv.js
@@ -0,0 +1,98 @@
+const crypto = require("crypto");
+
+// Defaults from config
+const algorithm = "aes256";
+const inputEncoding = "utf8";
+const outputEncoding = "hex";
+
+// Legacy decryption using createDecipher (no IV)
+function legacyDecrypt(encrypted, secret) {
+  const decipher = crypto.createDecipher(algorithm, secret);
+  let decrypted = decipher.update(encrypted, outputEncoding, inputEncoding);
+  decrypted += decipher.final(inputEncoding);
+  return decrypted;
+}
+
+// Legacy encryption using createCipher (no IV)
+function legacyEncrypt(value, secret) {
+  const cipher = crypto.createCipher(algorithm, secret);
+  let encrypted = cipher.update(value, inputEncoding, outputEncoding);
+  encrypted += cipher.final(outputEncoding);
+  return encrypted;
+}
+
+// New encryption using createCipheriv (with IV)
+function encryptWithIv(value, secret) {
+  const key = crypto.createHash("sha256").update(secret).digest();
+  const iv = crypto.randomBytes(16);
+  const cipher = crypto.createCipheriv(algorithm, key, iv);
+
+  let encrypted = cipher.update(value, inputEncoding, outputEncoding);
+  encrypted += cipher.final(outputEncoding);
+  return `V2:${iv.toString(outputEncoding)}:${encrypted}`;
+}
+
+// New decryption using createDecipheriv (with IV)
+function decryptWithIv(encrypted, secret) {
+  const key = crypto.createHash("sha256").update(secret).digest();
+  const parts = encrypted.split(":");
+  const iv = Buffer.from(parts[1], outputEncoding);
+  const encryptedData = parts[2];
+
+  const decipher = crypto.createDecipheriv(algorithm, key, iv);
+  let decrypted = decipher.update(encryptedData, outputEncoding, inputEncoding);
+  decrypted += decipher.final(inputEncoding);
+  return decrypted;
+}
+
+exports.up = function up(knex) {
+  const sessionSecret = process.env.SESSION_SECRET;
+  if (!sessionSecret) {
+    throw new Error("SESSION_SECRET must be set to run this migration");
+  }
+
+  return knex("messaging_service")
+    .select("messaging_service_sid", "encrypted_auth_token")
+    .whereNot("encrypted_auth_token", "")
+    .then((rows) => {
+      const updates = rows
+        .filter((row) => !row.encrypted_auth_token.startsWith("V2:"))
+        .map((row) => {
+          const decrypted = legacyDecrypt(
+            row.encrypted_auth_token,
+            sessionSecret
+          );
+          const reEncrypted = encryptWithIv(decrypted, sessionSecret);
+          return knex("messaging_service")
+            .where("messaging_service_sid", row.messaging_service_sid)
+            .update({ encrypted_auth_token: reEncrypted });
+        });
+      return Promise.all(updates);
+    });
+};
+
+exports.down = function down(knex) {
+  const sessionSecret = process.env.SESSION_SECRET;
+  if (!sessionSecret) {
+    throw new Error("SESSION_SECRET must be set to run this migration");
+  }
+
+  return knex("messaging_service")
+    .select("messaging_service_sid", "encrypted_auth_token")
+    .whereNot("encrypted_auth_token", "")
+    .then((rows) => {
+      const updates = rows
+        .filter((row) => row.encrypted_auth_token.startsWith("V2:"))
+        .map((row) => {
+          const decrypted = decryptWithIv(
+            row.encrypted_auth_token,
+            sessionSecret
+          );
+          const reEncrypted = legacyEncrypt(decrypted, sessionSecret);
+          return knex("messaging_service")
+            .where("messaging_service_sid", row.messaging_service_sid)
+            .update({ encrypted_auth_token: reEncrypted });
+        });
+      return Promise.all(updates);
+    });
+};
diff --git a/src/server/api/lib/crypto.js b/src/server/api/lib/crypto.js
index de7ccdda2..e54cbd623 100644
--- a/src/server/api/lib/crypto.js
+++ b/src/server/api/lib/crypto.js
@@ -1,7 +1,7 @@
 const { config } = require("../../../config");
 const crypto = require("crypto");
 
-const key = config.SESSION_SECRET;
+const key = crypto.createHash("sha256").update(config.SESSION_SECRET).digest();
 const algorithm = config.ENCRYPTION_ALGORITHM;
 const inputEncoding = config.ENCRYPTION_INPUT_ENCODING;
 const outputEncoding = config.ENCRYPTION_OUTPUT_ENCODING;
@@ -13,15 +13,27 @@ if (!key) {
 }
 
 const symmetricEncrypt = (value) => {
-  const cipher = crypto.createCipher(algorithm, key);
+  const iv = crypto.randomBytes(16);
+  const cipher = crypto.createCipheriv(algorithm, key, iv);
   let encrypted = cipher.update(value, inputEncoding, outputEncoding);
   encrypted += cipher.final(outputEncoding);
-  return encrypted;
+
+  // Prepend IV to encrypted data (IV is not secret) and prefix with V2
+  return `V2:${iv.toString(outputEncoding)}:${encrypted}`;
 };
 
 const symmetricDecrypt = (encrypted) => {
-  const decipher = crypto.createDecipher(algorithm, key);
-  let decrypted = decipher.update(encrypted, outputEncoding, inputEncoding);
+  // parts are V2, iv, and encrypted string
+  const parts = encrypted.split(":");
+  if (parts.length !== 3) {
+    throw new Error("Invalid encrypted data format");
+  }
+
+  const iv = Buffer.from(parts[1], outputEncoding);
+  const encryptedData = parts[2];
+
+  const decipher = crypto.createDecipheriv(algorithm, key, iv);
+  let decrypted = decipher.update(encryptedData, outputEncoding, inputEncoding);
   decrypted += decipher.final(inputEncoding);
   return decrypted;
 };