diff options
Diffstat (limited to 'lib/crypto/src/crypto.erl')
| -rw-r--r-- | lib/crypto/src/crypto.erl | 39 |
1 files changed, 38 insertions, 1 deletions
diff --git a/lib/crypto/src/crypto.erl b/lib/crypto/src/crypto.erl index 631af62615..4b386924cb 100644 --- a/lib/crypto/src/crypto.erl +++ b/lib/crypto/src/crypto.erl @@ -30,6 +30,8 @@ -export([hmac/3, hmac/4, hmac_init/2, hmac_update/2, hmac_final/1, hmac_final_n/2]). -export([cmac/3, cmac/4]). -export([exor/2, strong_rand_bytes/1, mod_pow/3]). +-export([strong_rand_uniform/0]). +-export([strong_rand_uniform/1]). -export([rand_uniform/2]). -export([block_encrypt/3, block_decrypt/3, block_encrypt/4, block_decrypt/4]). -export([next_iv/2, next_iv/3]). @@ -283,9 +285,11 @@ stream_decrypt(State, Data0) -> stream_crypt(fun do_stream_decrypt/2, State, Data, erlang:byte_size(Data), MaxByts, []). %% -%% RAND - pseudo random numbers using RN_ functions in crypto lib +%% RAND - pseudo random numbers using RN_ and BN_ functions in crypto lib %% -spec strong_rand_bytes(non_neg_integer()) -> binary(). +-spec strong_rand_uniform() -> float(). +-spec strong_rand_uniform(pos_integer()) -> pos_integer(). -spec rand_uniform(crypto_integer(), crypto_integer()) -> crypto_integer(). @@ -297,6 +301,38 @@ strong_rand_bytes(Bytes) -> strong_rand_bytes_nif(_Bytes) -> ?nif_stub. +strong_rand_uniform() -> + Sign = 0, % positive + Exponent = 1023, % on the interval [1.0, 2.0[ + Fraction = strong_rand_uniform(1, 1 bsl 52), % the whole interval above (except 1.0) + <<Value:64/big-float>> = <<Sign:1, Exponent:11, Fraction:52>>, + Value - 1.0. + +strong_rand_uniform(N) when is_integer(N), N >= 1 -> + 1 + strong_rand_uniform(0, N). + +strong_rand_uniform(From, To) when is_binary(From), is_binary(To) -> + case strong_rand_uniform_nif(From,To) of + false -> + erlang:error(low_entropy); + <<Len:32/integer, MSB, Rest/binary>> when MSB > 127 -> + <<(Len + 1):32/integer, 0, MSB, Rest/binary>>; + Whatever -> + Whatever + end; +strong_rand_uniform(From, To) when is_integer(From), is_integer(To), From < To -> + BinFrom = mpint(From), + BinTo = mpint(To), + case strong_rand_uniform(BinFrom, BinTo) of + Result when is_binary(Result) -> + erlint(Result); + Other -> + Other + end. + +strong_rand_uniform_nif(_From, _To) -> ?nif_stub. + + rand_uniform(From,To) when is_binary(From), is_binary(To) -> case rand_uniform_nif(From,To) of <<Len:32/integer, MSB, Rest/binary>> when MSB > 127 -> @@ -325,6 +361,7 @@ rand_uniform_pos(_,_) -> rand_uniform_nif(_From,_To) -> ?nif_stub. + -spec rand_seed(binary()) -> ok. rand_seed(Seed) -> rand_seed_nif(Seed). |