extmod/moducryptolib: Add AES-CTR support.

Selectable at compile time via MICROPY_PY_UCRYPTOLIB_CTR.  Disabled by
default.

1 files changed, 28 insertions, 0 deletions

diff --git a/tests/extmod/ucryptolib_aes128_ctr.py b/tests/extmod/ucryptolib_aes128_ctr.py
new file mode 100644
index 000000000..5a16b4529
--- /dev/null
+++ b/tests/extmod/ucryptolib_aes128_ctr.py
@@ -0,0 +1,28 @@
+try:
+    from ucryptolib import aes
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+
+def _new(k, ctr_initial):
+    return aes(k, 6, ctr_initial)
+
+
+try:
+    _new(b'x' * 16, b'x' * 16)
+except ValueError as e:
+    # is CTR support disabled?
+    if e.args[0] == "mode":
+        print("SKIP")
+        raise SystemExit
+    raise e
+
+crypto = _new(b"1234" * 4, b"5678" * 4)
+enc = crypto.encrypt(b'a')
+print(enc)
+enc += crypto.encrypt(b'b' * 1000)
+print(enc)
+
+crypto = _new(b"1234" * 4, b"5678" * 4)
+print(crypto.decrypt(enc))