diff options
Diffstat (limited to 'comm/third_party/botan/src/lib/pk_pad/emsa_x931/emsa_x931.cpp')
-rw-r--r-- | comm/third_party/botan/src/lib/pk_pad/emsa_x931/emsa_x931.cpp | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/pk_pad/emsa_x931/emsa_x931.cpp b/comm/third_party/botan/src/lib/pk_pad/emsa_x931/emsa_x931.cpp new file mode 100644 index 0000000000..b1f698f86d --- /dev/null +++ b/comm/third_party/botan/src/lib/pk_pad/emsa_x931/emsa_x931.cpp @@ -0,0 +1,102 @@ +/* +* EMSA_X931 +* (C) 1999-2007 Jack Lloyd +* +* Botan is released under the Simplified BSD License (see license.txt) +*/ + +#include <botan/emsa_x931.h> +#include <botan/exceptn.h> +#include <botan/hash_id.h> + +namespace Botan { + +namespace { + +secure_vector<uint8_t> emsa2_encoding(const secure_vector<uint8_t>& msg, + size_t output_bits, + const secure_vector<uint8_t>& empty_hash, + uint8_t hash_id) + { + const size_t HASH_SIZE = empty_hash.size(); + + size_t output_length = (output_bits + 1) / 8; + + if(msg.size() != HASH_SIZE) + throw Encoding_Error("EMSA_X931::encoding_of: Bad input length"); + if(output_length < HASH_SIZE + 4) + throw Encoding_Error("EMSA_X931::encoding_of: Output length is too small"); + + const bool empty_input = (msg == empty_hash); + + secure_vector<uint8_t> output(output_length); + + output[0] = (empty_input ? 0x4B : 0x6B); + output[output_length - 3 - HASH_SIZE] = 0xBA; + set_mem(&output[1], output_length - 4 - HASH_SIZE, 0xBB); + buffer_insert(output, output_length - (HASH_SIZE + 2), msg.data(), msg.size()); + output[output_length-2] = hash_id; + output[output_length-1] = 0xCC; + + return output; + } + +} + +std::string EMSA_X931::name() const + { + return "EMSA2(" + m_hash->name() + ")"; + } + +void EMSA_X931::update(const uint8_t input[], size_t length) + { + m_hash->update(input, length); + } + +secure_vector<uint8_t> EMSA_X931::raw_data() + { + return m_hash->final(); + } + +/* +* EMSA_X931 Encode Operation +*/ +secure_vector<uint8_t> EMSA_X931::encoding_of(const secure_vector<uint8_t>& msg, + size_t output_bits, + RandomNumberGenerator&) + { + return emsa2_encoding(msg, output_bits, m_empty_hash, m_hash_id); + } + +/* +* EMSA_X931 Verify Operation +*/ +bool EMSA_X931::verify(const secure_vector<uint8_t>& coded, + const secure_vector<uint8_t>& raw, + size_t key_bits) + { + try + { + return (coded == emsa2_encoding(raw, key_bits, + m_empty_hash, m_hash_id)); + } + catch(...) + { + return false; + } + } + +/* +* EMSA_X931 Constructor +*/ +EMSA_X931::EMSA_X931(HashFunction* hash) : m_hash(hash) + { + m_empty_hash = m_hash->final(); + + m_hash_id = ieee1363_hash_id(hash->name()); + + if(!m_hash_id) + throw Encoding_Error("EMSA_X931 no hash identifier for " + hash->name()); + } + +} |