[utils] Add pkcs1pad

Used in daisuki.net (#4738)

1 files changed, 15 insertions, 0 deletions

diff --git a/youtube_dl/utils.py b/youtube_dl/utils.py
index 17b83794a..8bd075eaf 100644
--- a/youtube_dl/utils.py
+++ b/youtube_dl/utils.py
@@ -3336,6 +3336,21 @@ def ohdave_rsa_encrypt(data, exponent, modulus):
     return '%x' % encrypted
 
 
+def pkcs1pad(data, length):
+    """
+    Padding input data with PKCS#1 scheme
+
+    @param {int[]} data        input data
+    @param {int}   length      target length
+    @returns {int[]}           padded data
+    """
+    if len(data) > length - 11:
+        raise ValueError('Input data too long for PKCS#1 padding')
+
+    pseudo_random = [random.randint(0, 254) for _ in range(length - len(data) - 3)]
+    return [0, 2] + pseudo_random + [0] + data
+
+
 def encode_base_n(num, n, table=None):
     FULL_TABLE = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
     if not table: