diff options
Diffstat (limited to 'cypher.cpp')
| -rw-r--r-- | cypher.cpp | 196 |
1 files changed, 88 insertions, 108 deletions
@@ -29,15 +29,15 @@ */ #include <stdexcept> -#include <vector> #include <iostream> +#include <string> #include "cypher.h" #include "keyDerivation.h" extern "C" { -#include <srtp/crypto_kernel.h> +#include <gcrypt.h> } void Cypher::cypher(Buffer& buf, seq_nr_t seq_nr, sender_id_t sender_id) @@ -65,129 +65,109 @@ Buffer NullCypher::getBitStream(u_int32_t length, seq_nr_t seq_nr, sender_id_t s } +const char* AesIcmCypher::MIN_GCRYPT_VERSION = "1.2.3"; +bool AesIcmCypher::gcrypt_initialized_ = false; + + +AesIcmCypher::AesIcmCypher() : salt_(Buffer(14)) +{ + gcry_error_t err; + if( !gcry_check_version( MIN_GCRYPT_VERSION ) ) + { + std::cerr << "Invalid Version of libgcrypt, should be >= "; + std::cerr << MIN_GCRYPT_VERSION << std::endl; + return; + } + + if( !gcrypt_initialized_ ) + { + /* Allocate a pool of secure memory. This also drops priviliges + on some systems. */ + err = gcry_control(GCRYCTL_INIT_SECMEM, GCRYPT_SEC_MEM, 0); + if( err ) + { + std::cerr << "Failed to allocate " << GCRYPT_SEC_MEM << "bytes of secure memory: "; + std::cerr << gpg_strerror( err ) << std::endl; + return; + } + gcrypt_initialized_ = true; + } + + /* Tell Libgcrypt that initialization has completed. */ + err = gcry_control(GCRYCTL_INITIALIZATION_FINISHED); + if( err ) + { + std::cerr << "Failed to finish the initialization of libgcrypt"; + std::cerr << gpg_strerror( err ) << std::endl; + return; + } + + gcry_cipher_open( &cipher_, GCRY_CIPHER_AES128, GCRY_CIPHER_MODE_CTR, 0 ); + + std::cout << "Keysize: " << gcry_cipher_get_algo_keylen( GCRY_CIPHER_AES128 ) << std::endl; +} + + +AesIcmCypher::~AesIcmCypher() +{ + gcry_cipher_close( cipher_ ); +} + + void AesIcmCypher::setKey(Buffer key) { - key_ = key; + gcry_error_t err; + err = gcry_cipher_setkey( cipher_, key.getBuf(), 16 ); + if( err ) + std::cerr << "Failed to set cipher key: " << gpg_strerror( err ) << std::endl; } void AesIcmCypher::setSalt(Buffer salt) { - salt = salt; + salt_ = salt; } Buffer AesIcmCypher::getBitStream(u_int32_t length, seq_nr_t seq_nr, sender_id_t sender_id) { + gcry_error_t err; + Buffer buf(length); - extern cipher_type_t aes_icm; - err_status_t status = err_status_ok; - cipher_t* cipher = NULL; - v128_t iv, sid, seq, salt; - - v128_set_to_zero(&iv); - v128_set_to_zero(&sid); - v128_set_to_zero(&seq); - v128_set_to_zero(&salt); - - // allocate cipher - // FIXXME: why we do not can do this??? -// status = cipher_type_alloc(&aes_icm, &cipher, key_.getLength()); - status = cipher_type_alloc(&aes_icm, &cipher, 30); - if( status ) + +// // set IV +// // where the 128-bit integer value IV SHALL be defined by the SSRC, the +// // SRTP packet index i, and the SRTP session salting key k_s, as below. +// // +// // IV = (k_s * 2^16) XOR (SSRC * 2^64) XOR (i * 2^16) +// // sizeof(k_s) = 112 bit, random + + Buffer iv(16), seq, sid; + + sid = sender_id; + seq = seq_nr; + + iv = (salt_.leftByteShift(2) ^ sid.leftByteShift(8)) ^ sid.leftByteShift(2); + + err = gcry_cipher_setiv( cipher_, iv.getBuf(), 0 ); + if( err ) + { + std::cerr << "Failed to set cipher IV: " << gpg_strerror( err ) << std::endl; return Buffer(0); + } + + err = gcry_cipher_reset( cipher_ ); + if( err ) + { + std::cerr << "Failed to reset cipher: " << gpg_strerror( err ) << std::endl; + return Buffer(0); + } - // init cipher - status = cipher_init(cipher, key_.getBuf(), direction_any); - if( status ) + err = gcry_cipher_encrypt( cipher_, buf, buf.getLength(), 0, 0 ); + if( err ) { - cipher_dealloc(cipher); + std::cerr << "Failed to generate cipher bitstream: " << gpg_strerror( err ) << std::endl; return Buffer(0); } - // set IV - // where the 128-bit integer value IV SHALL be defined by the SSRC, the - // SRTP packet index i, and the SRTP session salting key k_s, as below. - // - // IV = (k_s * 2^16) XOR (SSRC * 2^64) XOR (i * 2^16) - // sizeof(k_s) = 112 bit, random - - seq.v64[0] = seq_nr; - sid.v64[0] = sender_id; - v128_copy_octet_string(&salt, salt_.getBuf()); - v128_left_shift(&salt, 16); - v128_left_shift(&sid, 64); - v128_left_shift(&seq, 16); - - v128_xor(&iv, &salt, &sid); - v128_xor(&iv, &iv, &seq); - - status = cipher_set_iv(cipher, &iv); - if( status ) - cipher_dealloc(cipher); - - status = cipher_output(cipher, buf, length); - status = cipher_dealloc(cipher); return buf; } -// -//void AesIcmCypher::cypher(Buffer& buf, seq_nr_t seq_nr, sender_id_t sender_id) -//{ -// extern cipher_type_t aes_icm; -// err_status_t status = err_status_ok; -// cipher_t* cipher = NULL; -// uint32_t length = 0; -// v128_t iv, sid, seq, salt; -// -// v128_set_to_zero(&iv); -// v128_set_to_zero(&sid); -// v128_set_to_zero(&seq); -// v128_set_to_zero(&salt); -// -// std::cout << "AesIcmCypher::cypher called" << std::endl; -// // allocate cipher -// // FIXXME: why we do not can do this??? -//// status = cipher_type_alloc(&aes_icm, &cipher, key_.getLength()); -// status = cipher_type_alloc(&aes_icm, &cipher, 30); -// if( status ) -// return; -// -// // init cipher -// status = cipher_init(cipher, key_.getBuf(), direction_any); -// if( status ) -// { -// cipher_dealloc(cipher); -// return; -// } -// -// // set IV -// // where the 128-bit integer value IV SHALL be defined by the SSRC, the -// // SRTP packet index i, and the SRTP session salting key k_s, as below. -// // -// // IV = (k_s * 2^16) XOR (SSRC * 2^64) XOR (i * 2^16) -// // sizeof(k_s) = 112 bit, random -// -//// iv.v32[0] ^= 0; -//// iv.v32[1] ^= sender_id; -//// iv.v32[2] ^= (seq_nr >> 16); -//// iv.v32[3] ^= (seq_nr << 16); -// -// seq.v64[0] = seq_nr; -// sid.v64[0] = sender_id; -// v128_copy_octet_string(&salt, salt_.getBuf()); -// v128_left_shift(&salt, 16); -// v128_left_shift(&sid, 64); -// v128_left_shift(&seq, 16); -// -// v128_xor(&iv, &salt, &sid); -// v128_xor(&iv, &iv, &seq); -// -// status = cipher_set_iv(cipher, &iv); -// if( status ) -// cipher_dealloc(cipher); -// -// length = buf.getLength(); -// -// status = cipher_encrypt(cipher, buf, &length); -// status = cipher_dealloc(cipher); -//} -// |