diff --git a/bun.lock b/bun.lock
index ac0652b..0ce52ec 100644
--- a/bun.lock
+++ b/bun.lock
@@ -76,11 +76,13 @@
       "name": "@furtherverse/crypto",
       "version": "1.0.0",
       "dependencies": {
+        "node-forge": "^1.3.3",
         "openpgp": "catalog:",
       },
       "devDependencies": {
         "@furtherverse/tsconfig": "workspace:*",
         "@types/bun": "catalog:",
+        "@types/node-forge": "^1.3.14",
       },
     },
     "packages/tsconfig": {
@@ -562,6 +564,8 @@
 
     "@types/node": ["@types/node@24.11.0", "", { "dependencies": { "undici-types": "~7.16.0" } }, "sha512-fPxQqz4VTgPI/IQ+lj9r0h+fDR66bzoeMGHp8ASee+32OSGIkeASsoZuJixsQoVef1QJbeubcPBxKk22QVoWdw=="],
 
+    "@types/node-forge": ["@types/node-forge@1.3.14", "", { "dependencies": { "@types/node": "*" } }, "sha512-mhVF2BnD4BO+jtOp7z1CdzaK4mbuK0LLQYAvdOLqHTavxFNq4zA1EmYkpnFjP8HOUzedfQkRnp0E2ulSAYSzAw=="],
+
     "@types/plist": ["@types/plist@3.0.5", "", { "dependencies": { "@types/node": "*", "xmlbuilder": ">=11.0.1" } }, "sha512-E6OCaRmAe4WDmWNsL/9RMqdkkzDCY1etutkflWk4c+AcjDU07Pcz1fQwTX0TQz+Pxqn9i4L1TU3UFpjnrcDgxA=="],
 
     "@types/react": ["@types/react@19.2.14", "", { "dependencies": { "csstype": "^3.2.2" } }, "sha512-ilcTH/UniCkMdtexkoCN0bI7pMcJDvmQFPvuPvmEaYA/NSfFTAgdUSLAoVjaRJm7+6PvcM+q1zYOwS4wTYMF9w=="],
@@ -1142,6 +1146,8 @@
 
     "node-api-version": ["node-api-version@0.2.1", "", { "dependencies": { "semver": "^7.3.5" } }, "sha512-2xP/IGGMmmSQpI1+O/k72jF/ykvZ89JeuKX3TLJAYPDVLUalrshrLHkeVcCCZqG/eEa635cr8IBYzgnDvM2O8Q=="],
 
+    "node-forge": ["node-forge@1.3.3", "", {}, "sha512-rLvcdSyRCyouf6jcOIPe/BgwG/d7hKjzMKOas33/pHEr6gbq18IK9zV7DiPvzsz0oBJPme6qr6H6kGZuI9/DZg=="],
+
     "node-gyp": ["node-gyp@11.5.0", "", { "dependencies": { "env-paths": "^2.2.0", "exponential-backoff": "^3.1.1", "graceful-fs": "^4.2.6", "make-fetch-happen": "^14.0.3", "nopt": "^8.0.0", "proc-log": "^5.0.0", "semver": "^7.3.5", "tar": "^7.4.3", "tinyglobby": "^0.2.12", "which": "^5.0.0" }, "bin": { "node-gyp": "bin/node-gyp.js" } }, "sha512-ra7Kvlhxn5V9Slyus0ygMa2h+UqExPqUIkfk7Pc8QTLT956JLSy51uWFwHtIYy0vI8cB4BDhc/S03+880My/LQ=="],
 
     "node-releases": ["node-releases@2.0.36", "", {}, "sha512-TdC8FSgHz8Mwtw9g5L4gR/Sh9XhSP/0DEkQxfEFXOpiul5IiHgHan2VhYYb6agDSfp4KuvltmGApc8HMgUrIkA=="],
diff --git a/packages/crypto/package.json b/packages/crypto/package.json
index 6018329..05d28bd 100644
--- a/packages/crypto/package.json
+++ b/packages/crypto/package.json
@@ -7,10 +7,12 @@
     ".": "./src/index.ts"
   },
   "dependencies": {
+    "node-forge": "^1.3.3",
     "openpgp": "catalog:"
   },
   "devDependencies": {
     "@furtherverse/tsconfig": "workspace:*",
-    "@types/bun": "catalog:"
+    "@types/bun": "catalog:",
+    "@types/node-forge": "^1.3.14"
   }
 }
diff --git a/packages/crypto/src/rsa-oaep.ts b/packages/crypto/src/rsa-oaep.ts
index 1de1583..5304bed 100644
--- a/packages/crypto/src/rsa-oaep.ts
+++ b/packages/crypto/src/rsa-oaep.ts
@@ -1,34 +1,32 @@
-import { constants, createPublicKey, publicEncrypt } from 'node:crypto'
+import forge from 'node-forge'
 
 /**
  * RSA-OAEP encrypt with platform public key.
  *
- * Algorithm: RSA/ECB/OAEPWithSHA-256AndMGF1Padding
- * - OAEP hash: SHA-256
- * - MGF1 hash: SHA-256
+ * Matches Java's {@code Cipher.getInstance("RSA/ECB/OAEPWithSHA-256AndMGF1Padding")}
+ * with **default SunJCE parameters**:
+ *
+ * | Parameter | Value  |
+ * |-----------|--------|
+ * | OAEP hash | SHA-256|
+ * | MGF1 hash | SHA-1  |
+ *
+ * Node.js `crypto.publicEncrypt({ oaepHash })` ties both hashes together,
+ * so we use `node-forge` which allows independent configuration.
  *
  * @param plaintext - UTF-8 string to encrypt
- * @param publicKeyBase64 - Platform public key (X.509 DER, Base64 encoded)
+ * @param publicKeyBase64 - Platform RSA public key (X.509 / SPKI DER, Base64)
  * @returns Base64-encoded ciphertext
  */
 export const rsaOaepEncrypt = (plaintext: string, publicKeyBase64: string): string => {
-  // Load public key from Base64-encoded DER (X.509 / SubjectPublicKeyInfo)
-  const publicKeyDer = Buffer.from(publicKeyBase64, 'base64')
-  const publicKey = createPublicKey({
-    key: publicKeyDer,
-    format: 'der',
-    type: 'spki',
+  const derBytes = forge.util.decode64(publicKeyBase64)
+  const asn1 = forge.asn1.fromDer(derBytes)
+  const publicKey = forge.pki.publicKeyFromAsn1(asn1) as forge.pki.rsa.PublicKey
+
+  const encrypted = publicKey.encrypt(plaintext, 'RSA-OAEP', {
+    md: forge.md.sha256.create(),
+    mgf1: { md: forge.md.sha1.create() },
   })
 
-  // Encrypt with RSA-OAEP (SHA-256 for both OAEP hash and MGF1)
-  const encrypted = publicEncrypt(
-    {
-      key: publicKey,
-      padding: constants.RSA_PKCS1_OAEP_PADDING,
-      oaepHash: 'sha256',
-    },
-    Buffer.from(plaintext, 'utf-8'),
-  )
-
-  return encrypted.toString('base64')
+  return forge.util.encode64(encrypted)
 }