diff options
Diffstat (limited to 'modules/rng/x931_rng/x931_rng.cpp')
-rw-r--r-- | modules/rng/x931_rng/x931_rng.cpp | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/modules/rng/x931_rng/x931_rng.cpp b/modules/rng/x931_rng/x931_rng.cpp new file mode 100644 index 000000000..f4b0f71a9 --- /dev/null +++ b/modules/rng/x931_rng/x931_rng.cpp @@ -0,0 +1,142 @@ +/************************************************* +* ANSI X9.31 RNG Source File * +* (C) 1999-2008 Jack Lloyd * +*************************************************/ + +#include <botan/x931_rng.h> +#include <botan/lookup.h> +#include <botan/xor_buf.h> +#include <algorithm> + +namespace Botan { + +/************************************************* +* Generate a buffer of random bytes * +*************************************************/ +void ANSI_X931_RNG::randomize(byte out[], u32bit length) + { + if(!is_seeded()) + reseed(); + + while(length) + { + if(position == R.size()) + update_buffer(); + + const u32bit copied = std::min(length, R.size() - position); + + copy_mem(out, R + position, copied); + out += copied; + length -= copied; + position += copied; + } + } + +/************************************************* +* Refill the internal state * +*************************************************/ +void ANSI_X931_RNG::update_buffer() + { + SecureVector<byte> DT(cipher->BLOCK_SIZE); + + prng->randomize(DT, DT.size()); + cipher->encrypt(DT); + + xor_buf(R, V, DT, cipher->BLOCK_SIZE); + cipher->encrypt(R); + + xor_buf(V, R, DT, cipher->BLOCK_SIZE); + cipher->encrypt(V); + + position = 0; + } + +/************************************************* +* Reseed the internal state * +*************************************************/ +void ANSI_X931_RNG::reseed() + { + prng->reseed(); + + SecureVector<byte> key(cipher->MAXIMUM_KEYLENGTH); + prng->randomize(key, key.size()); + cipher->set_key(key, key.size()); + + if(V.size() != cipher->BLOCK_SIZE) + V.create(cipher->BLOCK_SIZE); + prng->randomize(V, V.size()); + + update_buffer(); + } + +/************************************************* +* Add a entropy source to the underlying PRNG * +*************************************************/ +void ANSI_X931_RNG::add_entropy_source(EntropySource* src) + { + prng->add_entropy_source(src); + } + +/************************************************* +* Add some entropy to the underlying PRNG * +*************************************************/ +void ANSI_X931_RNG::add_entropy(const byte input[], u32bit length) + { + prng->add_entropy(input, length); + } + +/************************************************* +* Check if the the PRNG is seeded * +*************************************************/ +bool ANSI_X931_RNG::is_seeded() const + { + return V.has_items(); + } + +/************************************************* +* Clear memory of sensitive data * +*************************************************/ +void ANSI_X931_RNG::clear() throw() + { + cipher->clear(); + prng->clear(); + R.clear(); + V.destroy(); + + position = 0; + } + +/************************************************* +* Return the name of this type * +*************************************************/ +std::string ANSI_X931_RNG::name() const + { + return "X9.31(" + cipher->name() + ")"; + } + +/************************************************* +* ANSI X931 RNG Constructor * +*************************************************/ +ANSI_X931_RNG::ANSI_X931_RNG(const std::string& cipher_name, + RandomNumberGenerator* prng_ptr) + { + if(!prng_ptr) + throw Invalid_Argument("ANSI_X931_RNG constructor: NULL prng"); + + prng = prng_ptr; + cipher = get_block_cipher(cipher_name); + + R.create(cipher->BLOCK_SIZE); + position = 0; + } + +/************************************************* +* ANSI X931 RNG Destructor * +*************************************************/ +ANSI_X931_RNG::~ANSI_X931_RNG() + { + delete cipher; + delete prng; + } + +} |