diff --git a/.gitignore b/.gitignore
index e1cfb91..e0b3772 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 /node_modules
 /.idea
 /lib
+/tmp
 /coverage
 .DS_Store
diff --git a/package-lock.json b/package-lock.json
index c70affb..e771a42 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -3199,10 +3199,11 @@
       ]
     },
     "node_modules/brace-expansion": {
-      "version": "1.1.11",
-      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.11.tgz",
-      "integrity": "sha512-iCuPHDFgrHX7H2vEI/5xpz07zSHB00TpugqhmYtVmMO6518mCuRMoOYFldEBl0g187ufozdaHgWKcYFb61qGiA==",
+      "version": "1.1.12",
+      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.12.tgz",
+      "integrity": "sha512-9T9UjW3r0UW5c1Q7GTwllptXwhvYmEzFhzMfZ9H7FQWt+uZePjZPjBP/W1ZEyZ1twGWom5/56TF4lPcqjnDHcg==",
       "dev": true,
+      "license": "MIT",
       "dependencies": {
         "balanced-match": "^1.0.0",
         "concat-map": "0.0.1"
@@ -10545,9 +10546,9 @@
       "integrity": "sha512-AKpaYlHn8t4SVbOHCy+b5+KKgvR4vrsD8vbvrbiQJps7fKDTkjkDry6ji0rUJjC0kzbNePLwzxq8iypo41qeWA=="
     },
     "brace-expansion": {
-      "version": "1.1.11",
-      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.11.tgz",
-      "integrity": "sha512-iCuPHDFgrHX7H2vEI/5xpz07zSHB00TpugqhmYtVmMO6518mCuRMoOYFldEBl0g187ufozdaHgWKcYFb61qGiA==",
+      "version": "1.1.12",
+      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.12.tgz",
+      "integrity": "sha512-9T9UjW3r0UW5c1Q7GTwllptXwhvYmEzFhzMfZ9H7FQWt+uZePjZPjBP/W1ZEyZ1twGWom5/56TF4lPcqjnDHcg==",
       "dev": true,
       "requires": {
         "balanced-match": "^1.0.0",
diff --git a/src/mdoc/model/Document.ts b/src/mdoc/model/Document.ts
index 27f9647..4ad7d3d 100644
--- a/src/mdoc/model/Document.ts
+++ b/src/mdoc/model/Document.ts
@@ -163,14 +163,14 @@ export class Document {
    *
    * @param {Object} params - The parameters object
    * @param {jose.JWK | Uint8Array} params.issuerPrivateKey - The issuer's private key either in JWK format or COSE_KEY format as buffer.
-   * @param {string | Uint8Array} params.issuerCertificate - The issuer's certificate in pem format or as a buffer.
+   * @param {string | Uint8Array | Array<string | Uint8Array>} params.issuerCertificate - The issuer's certificate in pem format, as a buffer, or an array.
    * @param {SupportedAlgs} params.alg - The algorhitm used for the MSO signature.
    * @param {string | Uint8Array} [params.kid] - The key id of the issuer's private key. default: issuerPrivateKey.kid
    * @returns {Promise<IssuerSignedDoc>} - The signed document
    */
   async sign(params: {
     issuerPrivateKey: jose.JWK | Uint8Array,
-    issuerCertificate: string | Uint8Array,
+    issuerCertificate: string | Uint8Array | Array<string | Uint8Array>,
     alg: SupportedAlgs,
     kid?: string | Uint8Array,
   }): Promise<IssuerSignedDocument> {
@@ -178,9 +178,15 @@ export class Document {
       throw new Error('No namespaces added');
     }
 
-    const issuerPublicKeyBuffer = typeof params.issuerCertificate === 'string' ?
-      fromPEM(params.issuerCertificate) :
-      params.issuerCertificate;
+    let issuerCertificateChain: Uint8Array[];
+
+    if (Array.isArray(params.issuerCertificate)) {
+      issuerCertificateChain = params.issuerCertificate.flatMap((cert) => (typeof cert === 'string' ? fromPEM(cert) : [cert]));
+    } else if (typeof params.issuerCertificate === 'string') {
+      issuerCertificateChain = fromPEM(params.issuerCertificate);
+    } else {
+      issuerCertificateChain = [params.issuerCertificate];
+    }
 
     const issuerPrivateKeyJWK = params.issuerPrivateKey instanceof Uint8Array ?
       COSEKeyToJWK(params.issuerPrivateKey) :
@@ -210,7 +216,7 @@ export class Document {
     const protectedHeader: ProtectedHeaders = { alg: params.alg };
     const unprotectedHeader: UnprotectedHeaders = {
       kid: params.kid ?? issuerPrivateKeyJWK.kid,
-      x5chain: [issuerPublicKeyBuffer],
+      x5chain: issuerCertificateChain.length === 1 ? issuerCertificateChain[0] : issuerCertificateChain,
     };
 
     const issuerAuth = await IssuerAuth.sign(
diff --git a/src/mdoc/utils.ts b/src/mdoc/utils.ts
index cf395f0..440043c 100644
--- a/src/mdoc/utils.ts
+++ b/src/mdoc/utils.ts
@@ -120,7 +120,19 @@ export function getRandomBytes(len: number) {
   return webcrypto.getRandomValues(new Uint8Array(len));
 }
 
-export function fromPEM(pem: string): Uint8Array {
-  const base64 = pem.replace(/-{5}(BEGIN|END) .*-{5}/gm, '').replace(/\s/gm, '');
-  return Buffer.from(base64, 'base64');
+export function fromPEM(pem: string): Uint8Array[] {
+  const certs = pem
+    .split(/-----END CERTIFICATE-----/)
+    .map((block) => block.trim())
+    .filter((block) => block.length > 0)
+    .map((block) => {
+      const fullBlock = `${block}\n-----END CERTIFICATE-----`;
+      const base64 = fullBlock
+        .replace(/-----BEGIN CERTIFICATE-----/, '')
+        .replace(/-----END CERTIFICATE-----/, '')
+        .replace(/\s+/g, '');
+      return Buffer.from(base64, 'base64');
+    });
+
+  return certs;
 }
diff --git a/tmp/device-response.mdl b/tmp/device-response.mdl
deleted file mode 100644
index add8202..0000000
Binary files a/tmp/device-response.mdl and /dev/null differ
diff --git a/tmp/ephemeral-reader-key b/tmp/ephemeral-reader-key
deleted file mode 100644
index cce6899..0000000
--- a/tmp/ephemeral-reader-key
+++ /dev/null
@@ -1 +0,0 @@
-Þ;Kž_rÝ›X@jã	4ÚH¦ùý

ˆü°•Ž,ëì”|
\ No newline at end of file
diff --git a/tmp/session-transcript b/tmp/session-transcript
deleted file mode 100644
index fdd4947..0000000
Binary files a/tmp/session-transcript and /dev/null differ