diff --git a/src/api/addAttachedSignature.ts b/src/api/addAttachedSignature.ts
index 48ee4a0..433bb4e 100644
--- a/src/api/addAttachedSignature.ts
+++ b/src/api/addAttachedSignature.ts
@@ -6,14 +6,14 @@ import { _getCadesCert } from '../helpers/_getCadesCert';
 import { _getDateObj } from '../helpers/_getDateObj';
 
 /**
- * Создает присоединенную подпись сообщения по отпечатку сертификата
+ * Добавляет присоединенную подпись к подписанному сообщению по отпечатку сертификата
  *
  * @param thumbprint - отпечаток сертификата
- * @param message - подписываемое сообщение
+ * @param signedMessage - подписанное сообщение
  * @returns подпись в формате PKCS#7
  */
 export const addAttachedSignature = _afterPluginsLoaded(
-  async (thumbprint: string, unencryptedMessage: string | ArrayBuffer): Promise<string> => {
+  async (thumbprint: string, signedMessage: string | ArrayBuffer): Promise<string> => {
     const { cadesplugin } = window;
     const cadesCertificate = await _getCadesCert(thumbprint);
 
@@ -47,7 +47,7 @@ export const addAttachedSignature = _afterPluginsLoaded(
         let messageBase64;
 
         try {
-          messageBase64 = Buffer.from(unencryptedMessage).toString('base64');
+          messageBase64 = Buffer.from(signedMessage).toString('base64');
         } catch (error) {
           console.error(error);
 
@@ -72,7 +72,7 @@ export const addAttachedSignature = _afterPluginsLoaded(
         let signature: string;
 
         try {
-          void (__cadesAsyncToken__ + cadesSignedData.VerifyCades(messageBase64, cadesplugin.CADESCOM_PKCS7_TYPE));
+          void (__cadesAsyncToken__ + cadesSignedData.VerifyCades(signedMessage, cadesplugin.CADESCOM_PKCS7_TYPE));
           signature = __cadesAsyncToken__ + cadesSignedData.CoSignCades(cadesSigner, cadesplugin.CADESCOM_PKCS7_TYPE);
         } catch (error) {
           console.error(error);
diff --git a/src/api/addDetachedSignature.test.ts b/src/api/addDetachedSignature.test.ts
index 6225f62..447ea23 100644
--- a/src/api/addDetachedSignature.test.ts
+++ b/src/api/addDetachedSignature.test.ts
@@ -3,6 +3,7 @@ import { rawCertificates, parsedCertificates } from '../__mocks__/certificates';
 import { createDetachedSignature } from './createDetachedSignature';
 import { _getCadesCert } from '../helpers/_getCadesCert';
 import { addDetachedSignature } from './addDetachedSignature';
+import { createHash } from './createHash';
 
 const [rawCertificateMock] = rawCertificates;
 const [parsedCertificateMock] = parsedCertificates;
@@ -21,6 +22,7 @@ const executionSteps = [
   Symbol('step 4'),
   Symbol('step 5'),
   Symbol('step 6'),
+  Symbol('step 7'),
 ];
 
 const executionFlow = {
@@ -32,7 +34,7 @@ const executionFlow = {
     propset_ContentEncoding: jest.fn(),
     propset_Content: jest.fn(),
     SignHash: jest.fn(() => executionSteps[4]),
-    VerifyCades: jest.fn(),
+    VerifyHash: jest.fn(),
     CoSignHash: jest.fn(() => executionSteps[6]),
   },
   [executionSteps[2]]: {
@@ -46,9 +48,13 @@ const executionFlow = {
   [executionSteps[4]]: 'signature',
   [executionSteps[5]]: {
     propset_Algorithm: jest.fn(),
+    propset_DataEncoding: jest.fn(),
+    Hash: jest.fn(),
+    Value: executionSteps[7],
     SetHashValue: jest.fn(),
   },
   [executionSteps[6]]: 'newSignature',
+  [executionSteps[7]]: 'hash',
 };
 
 window.cadesplugin.__defineExecutionFlow(executionFlow);
@@ -67,16 +73,40 @@ window.cadesplugin.CreateObjectAsync.mockImplementation((object) => {
 
 describe('addDetachedSignature', () => {
   test('uses specified certificate', async () => {
+    const originalBufferFrom = global.Buffer.from;
+
+    (global.Buffer.from as jest.Mock) = jest.fn(() => ({
+      toString: jest.fn(),
+    }));
+
     const signature = await createDetachedSignature(parsedCertificateMock.thumbprint, 'message');
-    await addDetachedSignature(parsedCertificateMock.thumbprint, signature);
+    const signatureHash = await createHash(signature);
+    await addDetachedSignature(parsedCertificateMock.thumbprint, signature, signatureHash);
 
     expect(_getCadesCert).toHaveBeenCalledWith(parsedCertificateMock.thumbprint);
+
+    expect(global.Buffer.from).toHaveBeenCalledTimes(1);
+
+    global.Buffer.from = originalBufferFrom;
   });
 
   test('returns new signature', async () => {
+    const originalBufferFrom = global.Buffer.from;
+
+    (global.Buffer.from as jest.Mock) = jest.fn(() => ({
+      toString: jest.fn(),
+    }));
+
     let signature = await createDetachedSignature(parsedCertificateMock.thumbprint, 'message');
-    signature = await addDetachedSignature(parsedCertificateMock.thumbprint, signature);
+    const signatureHash = await createHash(signature);
+    signature = await addDetachedSignature(parsedCertificateMock.thumbprint, signature, signatureHash);
+
+    expect(_getCadesCert).toHaveBeenCalledWith(parsedCertificateMock.thumbprint);
+
+    expect(global.Buffer.from).toHaveBeenCalledTimes(1);
 
     expect(signature).toEqual('newSignature');
+
+    global.Buffer.from = originalBufferFrom;
   });
 });
diff --git a/src/api/addDetachedSignature.ts b/src/api/addDetachedSignature.ts
index abd57d6..9503354 100644
--- a/src/api/addDetachedSignature.ts
+++ b/src/api/addDetachedSignature.ts
@@ -6,14 +6,15 @@ import { _getCadesCert } from '../helpers/_getCadesCert';
 import { _getDateObj } from '../helpers/_getDateObj';
 
 /**
- * Создает отсоединенную подпись хеша по отпечатку сертификата
+ * Добавляет отсоединенную подпись хеша к подписанному сообщению по отпечатку сертификата
  *
  * @param thumbprint - отпечаток сертификата
- * @param messageHash - хеш подписываемого сообщения, сгенерированный по ГОСТ Р 34.11-2012 256 бит
+ * @param signedMessage - подписанное сообщение
+ * @param messageHash - хеш подписанного сообщения, сгенерированный по ГОСТ Р 34.11-2012 256 бит
  * @returns подпись в формате PKCS#7
  */
 export const addDetachedSignature = _afterPluginsLoaded(
-  async (thumbprint: string, messageHash: string): Promise<string> => {
+  async (thumbprint: string, signedMessage: string | ArrayBuffer, messageHash: string): Promise<string> => {
     const { cadesplugin } = window;
     const cadesCertificate = await _getCadesCert(thumbprint);
 
@@ -74,7 +75,10 @@ export const addDetachedSignature = _afterPluginsLoaded(
         let signature: string;
 
         try {
-          void (__cadesAsyncToken__ + cadesSignedData.VerifyCades(cadesHashedData, cadesplugin.CADESCOM_PKCS7_TYPE));
+          void (
+            __cadesAsyncToken__ +
+            cadesSignedData.VerifyHash(cadesHashedData, signedMessage, cadesplugin.CADESCOM_PKCS7_TYPE)
+          );
           signature =
             __cadesAsyncToken__ +
             cadesSignedData.CoSignHash(cadesHashedData, cadesSigner, cadesplugin.CADESCOM_PKCS7_TYPE);