diff --git a/src/CBOR/CBOR.php b/src/CBOR/CBOR.php
deleted file mode 100644
index d1867ba..0000000
--- a/src/CBOR/CBOR.php
+++ /dev/null
@@ -1,45 +0,0 @@
-<?php declare(strict_types=1);
-
-/**
- * This file is part of the ATProto Core package.
- *
- * (c) Core Branch
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-
-namespace ATProto\Core\CBOR;
-
-use ATProto\Core\CBOR\MajorTypes\TextString;
-use ATProto\Core\CBOR\MajorTypes\UnsignedInteger;
-
-class CBOR
-{
-    public static function encode(string|int|array $data): string
-    {
-        switch (gettype($data)) {
-            case 'integer':
-                return UnsignedInteger::encode($data);
-            break;
-            case 'string':
-                return TextString::encode($data);
-            break;
-        }
-
-        throw new \ValueError("Unsupported type: " . gettype($data));
-    }
-
-    public static function decode(string $data): int|string
-    {
-        if (TextString::validate($data)) {
-            return TextString::decode($data);
-        }
-
-        if (UnsignedInteger::validate($data)) {
-            return UnsignedInteger::decode($data);
-        }
-
-        throw new \ValueError("Unsupported type.");
-    }
-}
diff --git a/src/CBOR/MajorTypes/ByteString.php b/src/CBOR/MajorTypes/ByteString.php
new file mode 100644
index 0000000..8ddf7b4
--- /dev/null
+++ b/src/CBOR/MajorTypes/ByteString.php
@@ -0,0 +1,80 @@
+<?php
+
+namespace ATProto\Core\CBOR\MajorTypes;
+
+use ValueError;
+
+class ByteString
+{
+    public const int MAJOR_TYPE = 0x02;
+
+    public static function validate(string $input): bool
+    {
+        return ((ord($input[0]) >> 5) & 0x07) === self::MAJOR_TYPE;
+    }
+
+    public static function encode(string $input): string
+    {
+        $len = strlen($input);
+
+        if ($len <= 0x17) {
+            $header = chr((self::MAJOR_TYPE << 5) | $len);
+        } else if ($len <= 0xFF) {
+            $header = chr((self::MAJOR_TYPE << 5) | 24) . chr($len);
+        } else if ($len <= 0xFFFF) {
+            $header = chr((self::MAJOR_TYPE << 5) | 25) . pack('n', $len);
+        } else if ($len <= 0xFFFFFFFF) {
+            $header = chr((self::MAJOR_TYPE << 5) | 26) . pack('N', $len);
+        } else {
+            $header = chr((self::MAJOR_TYPE << 5) | 27) . pack('J', $len);
+        }
+
+        return $header . $input;
+    }
+
+    public static function decode(string $input): string
+    {
+        if (! self::validate($input)) {
+            throw new ValueError("Invalid CBOR ByteString major type.");
+        }
+
+        $addInfo = ord($input[0]) & 0x1F;
+        $offset = 1;
+
+        if ($addInfo <= 23) {
+            $length = $addInfo;
+        }
+
+        if ($addInfo === 24) {
+            $length = ord($input[$offset]);
+            $offset += 1;
+        }
+
+        if ($addInfo === 25) {
+            $length = unpack('n', substr($input, $offset, 2))[1];
+            $offset += 2;
+        }
+
+        if ($addInfo === 26) {
+            $length = unpack('N', substr($input, $offset, 4))[1];
+            $offset += 4;
+        }
+
+        if ($addInfo === 27) {
+            $length = unpack('J', substr($input, $offset, 8))[1];
+            $offset += 8;
+        }
+
+        if (! isset($length)) {
+            throw new \ValueError('Invalid CBOR ByteString length information.');
+        }
+
+        $text = substr($input, $offset, $length);
+
+        if (strlen($text) !== $length) {
+            throw new \ValueError("Invalid CBOR ByteString length mismatch.");
+        }
+
+        return $text;
+    }
+}
diff --git a/tests/Unit/CBOR/CBORTest.php b/tests/Unit/CBOR/CBORTest.php
deleted file mode 100644
index d1adbf9..0000000
--- a/tests/Unit/CBOR/CBORTest.php
+++ /dev/null
@@ -1,78 +0,0 @@
-<?php declare(strict_types = 1);
-
-/**
- * This file is part of the ATProto Core package.
- *
- * (c) Core Branch
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-
-namespace Tests\Unit\CBOR;
-
-use ATProto\Core\CBOR\CBOR;
-use PHPUnit\Framework\Attributes\DataProvider;
-use PHPUnit\Framework\TestCase;
-
-class CBORTest extends TestCase
-{
-    #[DataProvider('validCases')]
-    public function testEncode(int|string $data, string $expected): void
-    {
-        $encoded = CBOR::encode($data);
-        $this->assertSame($expected, $encoded);
-    }
-
-    #[DataProvider('validCases')]
-    public function testDecode(int|string $expected, string $data): void
-    {
-        $actual = CBOR::decode($data);
-
-        $this->assertSame($expected, $actual);
-    }
-
-    public function testCBORDecodeThrowsExceptionWhenPassedUnsupportedType(): void
-    {
-        $this->expectException(\ValueError::class);
-        $this->expectExceptionMessage('Unsupported type.');
-
-        CBOR::decode("\x80"); // CBOR array
-    }
-
-    public function testCBOREncodeThrowsExceptionWhenPassedUnsupportedType(): void
-    {
-        $this->expectException(\ValueError::class);
-        $this->expectExceptionMessage('Unsupported type: array');
-
-        CBOR::encode(array());
-    }
-
-    /**
-     * @return array[]
-     */
-    public static function validCases(): array
-    {
-        return [
-            // Unsigned integer test cases
-            [1, hex2bin('01')], // 1 encoded as CBOR unsigned integer
-            [10, hex2bin('0a')], // 10 encoded as CBOR unsigned integer
-
-            // String test cases
-            ['hello', hex2bin('6568656C6C6F')], // "hello" encoded as CBOR text string
-//
-//            // Boolean test cases
-//            [[true], hex2bin('f5')], // true encoded as CBOR special type
-//            [[false], hex2bin('f4')], // false encoded as CBOR special type
-//
-//            // Null test case
-//            [[null], hex2bin('f6')], // null encoded as CBOR special type
-//
-//            // Array test cases
-//            [[[1, 2, 3]], hex2bin('83010203')], // [1, 2, 3] encoded as CBOR array
-//
-//            // Map test cases
-//            [[['key' => 'value']], hex2bin('a1636b65796576616c7565')], // {"key": "value"} encoded as CBOR map
-        ];
-    }
-}
diff --git a/tests/Unit/CBOR/MajorTypes/ByteStringTest.php b/tests/Unit/CBOR/MajorTypes/ByteStringTest.php
new file mode 100644
index 0000000..cbd5b0d
--- /dev/null
+++ b/tests/Unit/CBOR/MajorTypes/ByteStringTest.php
@@ -0,0 +1,81 @@
+<?php
+
+namespace Tests\Unit\CBOR\MajorTypes;
+
+use ATProto\Core\CBOR\MajorTypes\ByteString;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+
+class ByteStringTest extends TestCase
+{
+    #[DataProvider('provideValidCases')]
+    public function testValidate(string $input, string $header): void
+    {
+        $this->assertTrue(ByteString::validate($header . $input));
+    }
+
+    public static function provideValidCases(): array
+    {
+        return [
+            ['f', "\x41"],
+            ['fo', "\x42"],
+            ['foo', "\x43"],
+            ['foob', "\x44"],
+            ['fooba', "\x45"],
+            ['foobar', "\x46"],
+            [
+                str_repeat("This is a longer string.", 4),
+                "\x58\x60"
+            ],
+            [
+                str_repeat("This is a longer string.", 12),
+                "\x59\x01\x20"
+            ],
+            [
+                str_repeat("This is a longer string.", 2731),
+                "\x5A\x00\x01\x00\x08"
+            ],
+        ];
+    }
+
+    #[DataProvider('provideValidCases')]
+    public function testEncode(string $input, string $header): void
+    {
+        $expected = $header . $input;
+        $actual = ByteString::encode($input);
+
+        $this->assertSame(bin2hex($expected), bin2hex($actual));
+    }
+
+    #[DataProvider('provideValidCases')]
+    public function testDecode(string $input, string $header): void
+    {
+        $actual = ByteString::decode($header . $input);
+
+        $this->assertSame($input, $actual);
+    }
+
+    public function testDecodeThrowsExceptionForInvalidMajorType(): void
+    {
+        $this->expectException(\ValueError::class);
+        $this->expectExceptionMessage("Invalid CBOR ByteString major type.");
+
+        ByteString::decode("\x0C");
+    }
+
+    public function testDecodeThrowsExceptionForLengthMismatch(): void
+    {
+        $this->expectException(\ValueError::class);
+        $this->expectExceptionMessage("Invalid CBOR ByteString length mismatch.");
+
+        ByteString::decode("\x45\x66\x6F\x6F\x62");
+    }
+
+    public function testDecodeThrowsExceptionForInvalidAdditionalInformation(): void
+    {
+        $this->expectException(\ValueError::class);
+        $this->expectExceptionMessage("Invalid CBOR ByteString length information.");
+
+        ByteString::decode("\x5F");
+    }
+}