diff options
Diffstat (limited to 'frozen_deps/Cryptodome/Util/Counter.py')
| -rw-r--r-- | frozen_deps/Cryptodome/Util/Counter.py | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/frozen_deps/Cryptodome/Util/Counter.py b/frozen_deps/Cryptodome/Util/Counter.py index 423f91f..c67bc95 100644 --- a/frozen_deps/Cryptodome/Util/Counter.py +++ b/frozen_deps/Cryptodome/Util/Counter.py @@ -45,6 +45,7 @@ def new(nbits, prefix=b"", suffix=b"", initial_value=1, little_endian=False, all used. initial_value (integer): The initial value of the counter. Default value is 1. + Its length in bits must not exceed the argument ``nbits``. little_endian (boolean): If ``True``, the counter number will be encoded in little endian format. If ``False`` (default), in big endian format. @@ -61,6 +62,12 @@ def new(nbits, prefix=b"", suffix=b"", initial_value=1, little_endian=False, all if (nbits % 8) != 0: raise ValueError("'nbits' must be a multiple of 8") + iv_bl = initial_value.bit_length() + if iv_bl > nbits: + raise ValueError("Initial value takes %d bits but it is longer than " + "the counter (%d bits)" % + (iv_bl, nbits)) + # Ignore wraparound return {"counter_len": nbits // 8, "prefix": prefix, |