diff --git a/CHANGELOG.md b/CHANGELOG.md
index a48819c5..b6c22a5c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,7 +3,8 @@
 ## [next]
 
 * [utils] Added SIG_FLAGS and ANNOTATION_FLAGS to improve readability;
-* [utils] Reworked findByteRange to match in more cases where it was incompatible so far (it didn't allow optional spaces in the array).
+* [utils] Reworked findByteRange to match in more cases where it was incompatible so far (it didn't allow optional spaces in the array);
+* [utils] Deprecated extractSignature as it was never public-ready. Copied it in internal-utils to be used in tests. Will remove from `utils` in a next major release;
 * [placeholder-pdfkit010] Uses SIG_FLAGS and ANNOTATION_FLAGS instead of magic numbers;
 * [placeholder-pdfkit010] Allow passing in widgetRect to override the default [0, 0, 0, 0] one;
 * [placeholder-plain] Allow passing in widgetRect to override the default [0, 0, 0, 0] one;
diff --git a/packages/internal-utils/extractSignature.js b/packages/internal-utils/extractSignature.js
new file mode 100644
index 00000000..fe876b6c
--- /dev/null
+++ b/packages/internal-utils/extractSignature.js
@@ -0,0 +1,71 @@
+function getSubstringIndex(str, substring, n) {
+    var times = 0;
+    var index = null;
+
+    while (times < n && index !== -1) {
+        index = str.indexOf(substring, index + 1);
+        times += 1;
+    }
+
+    return index;
+};
+
+/**
+ * @typedef {Object} ExtractSignatureResult
+ * @property {number[]} ByteRange
+ * @property {Buffer} signature
+ * @property {Buffer} signedData
+ */
+
+/**
+ * Basic implementation of signature extraction.
+ *
+ * Really basic. Would work in the simplest of cases where there is only one signature
+ * in a document and ByteRange is only used once in it.
+ *
+ * @param {Buffer} pdf
+ * @param {number} signatureCount
+ * @returns {ExtractSignatureResult}
+ */
+function extractSignature (pdf, signatureCount) {
+    if (!(pdf instanceof Buffer)) {
+        throw new Error('PDF expected as Buffer.');
+    }
+
+    // const byteRangePos = pdf.indexOf('/ByteRange [');
+    var byteRangePos = getSubstringIndex(pdf, '/ByteRange [', signatureCount || 1);
+    if (byteRangePos === -1) {
+        throw new Error('Failed to locate ByteRange.');
+    }
+
+    var byteRangeEnd = pdf.indexOf(']', byteRangePos);
+    if (byteRangeEnd === -1) {
+        throw new Error('Failed to locate the end of the ByteRange.');
+    }
+
+    var byteRange = pdf.subarray(byteRangePos, byteRangeEnd + 1).toString();
+    var matches = (/\/ByteRange \[(\d+) +(\d+) +(\d+) +(\d+) *\]/).exec(byteRange);
+    if (matches === null) {
+        throw new Error('Failed to parse the ByteRange.');
+    }
+
+    var ByteRange = matches.slice(1).map(Number);
+    var signedData = Buffer.concat([
+        pdf.subarray(ByteRange[0], ByteRange[0] + ByteRange[1]),
+        pdf.subarray(ByteRange[2], ByteRange[2] + ByteRange[3]),
+    ]);
+
+    var signatureHex = pdf.subarray(ByteRange[0] + ByteRange[1] + 1, ByteRange[2])
+        .toString('binary')
+        .replace(/(?:00|>)+$/, '');
+
+    var signature = Buffer.from(signatureHex, 'hex').toString('binary');
+
+    return {
+        ByteRange: matches.slice(1, 5).map(Number),
+        signature: signature,
+        signedData: signedData,
+    };
+};
+
+module.exports = extractSignature;
\ No newline at end of file
diff --git a/packages/internal-utils/index.js b/packages/internal-utils/index.js
index bff02084..879ac2f2 100644
--- a/packages/internal-utils/index.js
+++ b/packages/internal-utils/index.js
@@ -1,7 +1,9 @@
 var readTestResource = require('./readTestResource');
 var createPdfkitDocument = require('./createPdfkitDocument');
+var extractSignature = require('./extractSignature');
 
 module.exports = {
     readTestResource: readTestResource,  
     createPdfkitDocument: createPdfkitDocument,  
+    extractSignature: extractSignature,  
 }
\ No newline at end of file
diff --git a/packages/signpdf/src/signpdf.test.js b/packages/signpdf/src/signpdf.test.js
index 2eade1e8..3d4d5a64 100644
--- a/packages/signpdf/src/signpdf.test.js
+++ b/packages/signpdf/src/signpdf.test.js
@@ -1,12 +1,8 @@
 import {pdfkitAddPlaceholder} from '@signpdf/placeholder-pdfkit010';
 import {plainAddPlaceholder} from '@signpdf/placeholder-plain';
 import {P12Signer} from '@signpdf/signer-p12';
-import {
-    extractSignature,
-    Signer,
-    SignPdfError,
-} from '@signpdf/utils';
-import {readTestResource, createPdfkitDocument} from '@signpdf/internal-utils';
+import {Signer, SignPdfError} from '@signpdf/utils';
+import {readTestResource, createPdfkitDocument, extractSignature} from '@signpdf/internal-utils';
 import signpdf from './signpdf';
 
 /**
diff --git a/packages/utils/dist/extractSignature.d.ts b/packages/utils/dist/extractSignature.d.ts
index 8e5418a9..db791f27 100644
--- a/packages/utils/dist/extractSignature.d.ts
+++ b/packages/utils/dist/extractSignature.d.ts
@@ -1,2 +1,11 @@
-export function extractSignature(pdf: Buffer, signatureCount?: number): any;
+/**
+ * @type {(pdf: Buffer, signatureCount: number) => ExtractSignatureResult}
+ * @deprecated Should be used from internal-utils. Will be removed in a major release.
+ */
+export const extractSignature: (pdf: Buffer, signatureCount: number) => ExtractSignatureResult;
+export type ExtractSignatureResult = {
+    ByteRange: number[];
+    signature: Buffer;
+    signedData: Buffer;
+};
 //# sourceMappingURL=extractSignature.d.ts.map
\ No newline at end of file
diff --git a/packages/utils/dist/extractSignature.d.ts.map b/packages/utils/dist/extractSignature.d.ts.map
index c78b8650..5f72592d 100644
--- a/packages/utils/dist/extractSignature.d.ts.map
+++ b/packages/utils/dist/extractSignature.d.ts.map
@@ -1 +1 @@
-{"version":3,"file":"extractSignature.d.ts","sourceRoot":"","sources":["../src/extractSignature.js"],"names":[],"mappings":"AAsBO,sCAHI,MAAM,gCAsDhB"}
\ No newline at end of file
+{"version":3,"file":"extractSignature.d.ts","sourceRoot":"","sources":["../src/extractSignature.js"],"names":[],"mappings":"AAsFA;;;GAGG;AACH,qCAHgB,MAAM,kBAAkB,MAAM,KAAK,sBAAsB,CAG4F;;eAzEvJ,MAAM,EAAE;eACR,MAAM;gBACN,MAAM"}
\ No newline at end of file
diff --git a/packages/utils/dist/extractSignature.js b/packages/utils/dist/extractSignature.js
index f54dd017..72ea74b4 100644
--- a/packages/utils/dist/extractSignature.js
+++ b/packages/utils/dist/extractSignature.js
@@ -4,7 +4,9 @@ Object.defineProperty(exports, "__esModule", {
   value: true
 });
 exports.extractSignature = void 0;
+var _util = _interopRequireDefault(require("util"));
 var _SignPdfError = require("./SignPdfError");
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
 const getSubstringIndex = (str, substring, n) => {
   let times = 0;
   let index = null;
@@ -14,16 +16,26 @@ const getSubstringIndex = (str, substring, n) => {
   }
   return index;
 };
+
+/**
+ * @typedef {Object} ExtractSignatureResult
+ * @property {number[]} ByteRange
+ * @property {Buffer} signature
+ * @property {Buffer} signedData
+ */
+
 /**
  * Basic implementation of signature extraction.
  *
- * Really basic. Would work in the simplest of cases where there is only one signature
- * in a document and ByteRange is only used once in it.
+ * Really basic. Would work in the simplest of cases.
  *
  * @param {Buffer} pdf
- * @returns {Object} {ByteRange: Number[], signature: Buffer, signedData: Buffer}
+ * @param {number} signatureCount
+ * @returns {ExtractSignatureResult}
+ *
+ * @deprecated Should be used internally from internal-utils. Will be removed in a major release.
  */
-const extractSignature = (pdf, signatureCount = 1) => {
+const extractSignatureDeprecated = (pdf, signatureCount = 1) => {
   if (!(pdf instanceof Buffer)) {
     throw new _SignPdfError.SignPdfError('PDF expected as Buffer.', _SignPdfError.SignPdfError.TYPE_INPUT);
   }
@@ -52,4 +64,9 @@ const extractSignature = (pdf, signatureCount = 1) => {
     signedData
   };
 };
-exports.extractSignature = extractSignature;
\ No newline at end of file
+
+/**
+ * @type {(pdf: Buffer, signatureCount: number) => ExtractSignatureResult}
+ * @deprecated Should be used from internal-utils. Will be removed in a major release.
+ */
+const extractSignature = exports.extractSignature = _util.default.deprecate(extractSignatureDeprecated, 'Should be used internally from internal-utils. Will be removed in a major release.');
\ No newline at end of file
diff --git a/packages/utils/src/__snapshots__/extractSignature.test.js.snap b/packages/utils/src/__snapshots__/extractSignature.test.js.snap
index 92d7feae..40c5f71c 100644
Binary files a/packages/utils/src/__snapshots__/extractSignature.test.js.snap and b/packages/utils/src/__snapshots__/extractSignature.test.js.snap differ
diff --git a/packages/utils/src/extractSignature.js b/packages/utils/src/extractSignature.js
index 6f47a09b..fd00626c 100644
--- a/packages/utils/src/extractSignature.js
+++ b/packages/utils/src/extractSignature.js
@@ -1,3 +1,4 @@
+import nodeUtil from 'util';
 import {SignPdfError} from './SignPdfError';
 
 const getSubstringIndex = (str, substring, n) => {
@@ -11,16 +12,26 @@ const getSubstringIndex = (str, substring, n) => {
 
     return index;
 };
+
+/**
+ * @typedef {Object} ExtractSignatureResult
+ * @property {number[]} ByteRange
+ * @property {Buffer} signature
+ * @property {Buffer} signedData
+ */
+
 /**
  * Basic implementation of signature extraction.
  *
- * Really basic. Would work in the simplest of cases where there is only one signature
- * in a document and ByteRange is only used once in it.
+ * Really basic. Would work in the simplest of cases.
  *
  * @param {Buffer} pdf
- * @returns {Object} {ByteRange: Number[], signature: Buffer, signedData: Buffer}
+ * @param {number} signatureCount
+ * @returns {ExtractSignatureResult}
+ *
+ * @deprecated Should be used internally from internal-utils. Will be removed in a major release.
  */
-export const extractSignature = (pdf, signatureCount = 1) => {
+const extractSignatureDeprecated = (pdf, signatureCount = 1) => {
     if (!(pdf instanceof Buffer)) {
         throw new SignPdfError(
             'PDF expected as Buffer.',
@@ -72,3 +83,9 @@ export const extractSignature = (pdf, signatureCount = 1) => {
         signedData,
     };
 };
+
+/**
+ * @type {(pdf: Buffer, signatureCount: number) => ExtractSignatureResult}
+ * @deprecated Should be used from internal-utils. Will be removed in a major release.
+ */
+export const extractSignature = nodeUtil.deprecate(extractSignatureDeprecated, 'Should be used internally from internal-utils. Will be removed in a major release.');