diff --git a/packages/crypto/src/EncryptionFormats/EncryptionFormats.ts b/packages/crypto/src/EncryptionFormats/EncryptionFormats.ts
index f58a073b..fb62a50b 100644
--- a/packages/crypto/src/EncryptionFormats/EncryptionFormats.ts
+++ b/packages/crypto/src/EncryptionFormats/EncryptionFormats.ts
@@ -1,3 +1,4 @@
+import sodium from 'libsodium-wrappers';
 import { InvalidArgument } from '@tanker/errors';
 
 import { EncryptionV1 } from './v1';
@@ -50,8 +51,10 @@ export const extractEncryptionFormat = (encryptedData: Uint8Array) => {
 
   const encryption = encryptionFormats[version];
 
-  if (!encryption)
-    throw new InvalidArgument(`Unhandled format version ${version} used in encryptedData`);
+  if (!encryption) {
+    const headerHex = sodium.to_hex(encryptedData.slice(0, 5));
+    throw new InvalidArgument(`Unhandled format version ${version} used in encryptedData. Header starts with: 0x${headerHex}`);
+  }
   if (encryptedData.length < encryption.overhead)
     throw new InvalidArgument(`Truncated encrypted data. Length should be at least ${encryption.overhead} with encryption format v${encryption.version}`);
 
diff --git a/packages/crypto/src/__tests__/types.spec.ts b/packages/crypto/src/__tests__/types.spec.ts
index 1320944a..435393c8 100644
--- a/packages/crypto/src/__tests__/types.spec.ts
+++ b/packages/crypto/src/__tests__/types.spec.ts
@@ -52,6 +52,11 @@ describe('Resource', () => {
     expect(() => extractEncryptionFormat(incorrectVersion)).to.throw(InvalidArgument);
   });
 
+  it('should return the first 5 bytes as hex when unsupported format version is detected', () => {
+    const elf = new Uint8Array([0x7F, 0x45, 0x4C, 0x46, 0x2, 0x1, 0x1]);
+    expect(() => extractEncryptionFormat(elf)).to.throw('Header starts with: 0x7f454c4602');
+  });
+
   configs.forEach(({ version, testVector }) => {
     it(`should detect a buffer v${version}`, () => {
       const resource = utils.concatArrays(new Uint8Array([version]), testVector);