Updated vectors to include secret.
diff --git a/tests/hazmat/primitives/vectors/oath/rfc-4226.txt b/tests/hazmat/primitives/vectors/oath/rfc-4226.txt
index 377f155..35f7f8d 100644
--- a/tests/hazmat/primitives/vectors/oath/rfc-4226.txt
+++ b/tests/hazmat/primitives/vectors/oath/rfc-4226.txt
@@ -6,57 +6,75 @@
 INTERMEDIATE = cc93cf18508d94934c64b65d8ba7667fb7cde4b0
 TRUNCATED = 4c93cf18
 HOTP = 755224
+SECRET = 12345678901234567890
 
 COUNT = 1
 COUNTER = 1
 INTERMEDIATE = 75a48a19d4cbe100644e8ac1397eea747a2d33ab
 TRUNCATED = 41397eea
 HOTP = 287082
+SECRET = 12345678901234567890
+
 
 COUNT = 2
 COUNTER = 2
 INTERMEDIATE = 0bacb7fa082fef30782211938bc1c5e70416ff44
 TRUNCATED = 82fef30
 HOTP = 359152
+SECRET = 12345678901234567890
+
 
 COUNT = 3
 COUNTER = 3
 INTERMEDIATE = 66c28227d03a2d5529262ff016a1e6ef76557ece
 TRUNCATED = 66ef7655
 HOTP = 969429
+SECRET = 12345678901234567890
+
 
 COUNT = 4
 COUNTER = 4
 INTERMEDIATE = a904c900a64b35909874b33e61c5938a8e15ed1c
 TRUNCATED = 61c5938a
 HOTP = 338314
+SECRET = 12345678901234567890
+
 
 COUNT = 5
 COUNTER = 5
 INTERMEDIATE = a37e783d7b7233c083d4f62926c7a25f238d0316
 TRUNCATED = 33c083d4
 HOTP = 254676
+SECRET = 12345678901234567890
+
 
 COUNT = 6
 COUNTER = 6
 INTERMEDIATE = bc9cd28561042c83f219324d3c607256c03272ae
 TRUNCATED = 7256c032
 HOTP = 287922
+SECRET = 12345678901234567890
+
 
 COUNT = 7
 COUNTER = 7
 INTERMEDIATE = a4fb960c0bc06e1eabb804e5b397cdc4b45596fa
 TRUNCATED = 4e5b397
 HOTP = 162583
+SECRET = 12345678901234567890
+
 
 COUNT = 8
 COUNTER = 8
 INTERMEDIATE = 1b3c89f65e6c9e883012052823443f048b4332db
 TRUNCATED = 2823443f
 HOTP = 399871
+SECRET = 12345678901234567890
+
 
 COUNT = 9
 COUNTER = 9
 INTERMEDIATE = 1637409809a679dc698207310c8c7fc07290d9e5
 TRUNCATED = 2679dc69
 HOTP = 520489
+SECRET = 12345678901234567890
diff --git a/tests/hazmat/primitives/vectors/oath/rfc-6238.txt b/tests/hazmat/primitives/vectors/oath/rfc-6238.txt
index bec4ed2..5c2fa11 100644
--- a/tests/hazmat/primitives/vectors/oath/rfc-6238.txt
+++ b/tests/hazmat/primitives/vectors/oath/rfc-6238.txt
@@ -5,88 +5,106 @@
 TIME = 59
 TOTP = 94287082
 MODE = SHA1
+SECRET = 12345678901234567890
 
 COUNT = 1
 TIME = 59
 TOTP = 46119246
 MODE = SHA256
+SECRET = 12345678901234567890
 
 COUNT = 2
 TIME = 59
 TOTP = 90693936
 MODE = SHA512
+SECRET = 12345678901234567890
 
 COUNT = 3
 TIME = 1111111109
 TOTP = 07081804
 MODE = SHA1
+SECRET = 12345678901234567890
 
 COUNT = 4
 TIME = 1111111109
 TOTP = 68084774
 MODE = SHA256
+SECRET = 12345678901234567890
 
 COUNT = 5
 TIME = 1111111109
 TOTP = 25091201
 MODE = SHA512
+SECRET = 12345678901234567890
 
 COUNT = 6
 TIME = 1111111111
 TOTP = 14050471
 MODE = SHA1
+SECRET = 12345678901234567890
 
 COUNT = 7
 TIME = 1111111111
 TOTP = 67062674
 MODE = SHA256
+SECRET = 12345678901234567890
 
 COUNT = 8
 TIME = 1111111111
 TOTP = 99943326
 MODE = SHA512
+SECRET = 12345678901234567890
 
 COUNT = 9
 TIME = 1234567890
 TOTP = 89005924
 MODE = SHA1
+SECRET = 12345678901234567890
 
 COUNT = 10
 TIME = 1234567890
 TOTP = 91819424
 MODE = SHA256
+SECRET = 12345678901234567890
 
 COUNT = 11
 TIME = 1234567890
 TOTP = 93441116
 MODE = SHA512
+SECRET = 12345678901234567890
 
 COUNT = 12
 TIME = 2000000000
 TOTP = 69279037
 MODE = SHA1
+SECRET = 12345678901234567890
 
 COUNT = 13
 TIME = 2000000000
 TOTP = 69279037
 MODE = SHA256
+SECRET = 12345678901234567890
 
 COUNT = 14
 TIME = 2000000000
 TOTP = 69279037
 MODE = SHA512
+SECRET = 12345678901234567890
 
 COUNT = 15
 TIME = 20000000000
 TOTP = 65353130
 MODE = SHA1
+SECRET = 12345678901234567890
 
 COUNT = 16
 TIME = 20000000000
 TOTP = 77737706
 MODE = SHA256
+SECRET = 12345678901234567890
 
 COUNT = 17
 TIME = 20000000000
 TOTP = 47863826
 MODE = SHA512
+SECRET = 12345678901234567890
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 901c028..a0571ad 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -838,24 +838,30 @@
     INTERMEDIATE = cc93cf18508d94934c64b65d8ba7667fb7cde4b0
     TRUNCATED = 4c93cf18
     HOTP = 755224
+    SECRET = 12345678901234567890
 
     COUNT = 1
     COUNTER = 1
     INTERMEDIATE = 75a48a19d4cbe100644e8ac1397eea747a2d33ab
     TRUNCATED = 41397eea
     HOTP = 287082
+    SECRET = 12345678901234567890
+
 
     COUNT = 2
     COUNTER = 2
     INTERMEDIATE = 0bacb7fa082fef30782211938bc1c5e70416ff44
     TRUNCATED = 82fef30
     HOTP = 359152
+    SECRET = 12345678901234567890
+
 
     COUNT = 3
     COUNTER = 3
     INTERMEDIATE = 66c28227d03a2d5529262ff016a1e6ef76557ece
     TRUNCATED = 66ef7655
     HOTP = 969429
+    SECRET = 12345678901234567890
     """).splitlines()
 
     assert load_nist_vectors(vector_data) == [
@@ -864,24 +870,28 @@
             "intermediate": b"cc93cf18508d94934c64b65d8ba7667fb7cde4b0",
             "truncated": b"4c93cf18",
             "hotp": b"755224",
+            "secret": b"12345678901234567890",
         },
         {
             "counter": b"1",
             "intermediate": b"75a48a19d4cbe100644e8ac1397eea747a2d33ab",
             "truncated": b"41397eea",
             "hotp": b"287082",
+            "secret": b"12345678901234567890",
         },
         {
             "counter": b"2",
             "intermediate": b"0bacb7fa082fef30782211938bc1c5e70416ff44",
             "truncated": b"82fef30",
             "hotp": b"359152",
+            "secret": b"12345678901234567890",
         },
         {
             "counter": b"3",
             "intermediate": b"66c28227d03a2d5529262ff016a1e6ef76557ece",
             "truncated": b"66ef7655",
             "hotp": b"969429",
+            "secret": b"12345678901234567890",
         },
     ]
 
@@ -895,16 +905,19 @@
     TIME = 59
     TOTP = 94287082
     MODE = SHA1
+    SECRET = 12345678901234567890
 
     COUNT = 1
     TIME = 59
     TOTP = 46119246
     MODE = SHA256
+    SECRET = 12345678901234567890
 
     COUNT = 2
     TIME = 59
     TOTP = 90693936
     MODE = SHA512
+    SECRET = 12345678901234567890
     """).splitlines()
 
     assert load_nist_vectors(vector_data) == [
@@ -912,15 +925,18 @@
             "time": b"59",
             "totp": b"94287082",
             "mode": b"SHA1",
+            "secret": b"12345678901234567890",
         },
         {
             "time": b"59",
             "totp": b"46119246",
             "mode": b"SHA256",
+            "secret": b"12345678901234567890",
         },
         {
             "time": b"59",
             "totp": b"90693936",
             "mode": b"SHA512",
+            "secret": b"12345678901234567890",
         },
     ]