diff options
Diffstat (limited to 'libcmix')
| -rw-r--r-- | libcmix/cmix.c | 73 | ||||
| -rw-r--r-- | libcmix/cmix.h | 19 |
2 files changed, 77 insertions, 15 deletions
diff --git a/libcmix/cmix.c b/libcmix/cmix.c index a47a9fa..4465011 100644 --- a/libcmix/cmix.c +++ b/libcmix/cmix.c @@ -46,7 +46,6 @@ struct CMixContext initialize_cmix_context(struct Api api) { .s = NULL, .permutation = NULL, .pirs = NULL, - .messages = NULL }; } @@ -55,13 +54,11 @@ void release_mix(struct CMixContext* ctx) { ctx->api.free_group_element(ctx->r[i]); ctx->api.free_group_element(ctx->s[i]); ctx->api.free_group_element(ctx->pirs[i]); - ctx->api.free_group_element(ctx->messages[i]); } free(ctx->r); free(ctx->s); free(ctx->permutation); free(ctx->pirs); - free(ctx->messages); } void deinitialize(struct CMixContext* ctx) @@ -71,7 +68,7 @@ void deinitialize(struct CMixContext* ctx) ctx->api.deinitialize(); } -void element_to_buffer(struct CMixContext const* ctx, char* out_buffer, GroupElement element) { +void element_to_buffer(struct CMixContext const* ctx, char* out_buffer, GroupElement const element) { size_t el_size = get_group_element_array_size(ctx); unsigned char* buffer; @@ -110,8 +107,7 @@ enum cmix_error alloc_mix(struct CMixContext* ctx) { ctx->s = (GroupElement*) calloc(ctx->nr_participants, sizeof(GroupElement)); ctx->permutation = (unsigned int*) calloc(ctx->nr_participants, sizeof(unsigned int)); ctx->pirs = (GroupElement*) calloc(ctx->nr_participants, sizeof(GroupElement)); - ctx->pirs = (GroupElement*) calloc(ctx->nr_participants, sizeof(GroupElement)); - if(!ctx->r || !ctx->s || !ctx->permutation || !ctx->pirs || !ctx->messages) { + if(!ctx->r || !ctx->s || !ctx->permutation || !ctx->pirs) { return out_of_memory; } return no_error; @@ -132,8 +128,11 @@ enum cmix_error initialize_mix_randomness(struct CMixContext* ctx) { return no_error; } -enum cmix_error generate_random_message(struct CMixContext* ctx, size_t index) { - ctx->messages[index] = ctx->api.get_group_element(true); +enum cmix_error generate_random_message(struct CMixContext* ctx, char* buffer) { + GroupElement el = ctx->api.get_group_element(true); + element_to_buffer(ctx, buffer, el); + ctx->api.free_group_element(el); + return no_error; } @@ -185,7 +184,7 @@ enum cmix_error encrypt_r_and_multiply(struct CMixContext const* ctx, char* rand return no_error; } -enum cmix_error multiply_s(struct CMixContext const* ctx, char* r_out_buffer, char* m_out_buffer, char const* r_in_buffer, char const* m_in_buffer, size_t index) { +enum cmix_error multiply_encrypted_s(struct CMixContext const* ctx, char* r_out_buffer, char* m_out_buffer, char const* r_in_buffer, char const* m_in_buffer, size_t index) { size_t el_size = get_group_element_array_size(ctx); GroupElement random_r = ctx->api.array_to_element(r_in_buffer, el_size, true); @@ -210,9 +209,23 @@ enum cmix_error multiply_s(struct CMixContext const* ctx, char* r_out_buffer, ch return no_error; } +enum cmix_error multiply_s(struct CMixContext const* ctx, char* out_buffer, char const* message, size_t index) { + size_t el_size = get_group_element_array_size(ctx); + + GroupElement message_el = ctx->api.array_to_element(message, el_size, false); + GroupElement mult = ctx->api.multiply(message_el, ctx->s[ctx->permutation[index]], false); + + element_to_buffer(ctx, out_buffer, mult); + + ctx->api.free_group_element(message_el); + ctx->api.free_group_element(mult); + + return no_error; +} + enum cmix_error key_exchange_init(struct CMixContext const* ctx, char* pubkey_buffer, char* value_buffer, GroupElement* priv_el) { *priv_el = ctx->api.get_group_element(true); - GroupElement value = ctx->api.get_key_exchange_value(priv_el); + GroupElement value = ctx->api.get_key_exchange_value(*priv_el); get_public_key(ctx, pubkey_buffer); element_to_buffer(ctx, value_buffer, value); @@ -239,7 +252,7 @@ enum cmix_error key_exchange_responder(struct CMixContext const* ctx, GroupEleme enum cmix_error key_exchange_initiator(struct CMixContext const* ctx, GroupElement* shared_key, char const* pubkey, char const* value, GroupElement* priv_el) { size_t el_len = get_group_element_array_size(ctx); - *shared_key = ctx->api.derive_shared_key(ctx->keypair, (unsigned char*)pubkey, el_len, (unsigned char*)value, el_len, priv_el, false); + *shared_key = ctx->api.derive_shared_key(ctx->keypair, (unsigned char*)pubkey, el_len, (unsigned char*)value, el_len, *priv_el, false); ctx->api.free_group_element(*priv_el); *priv_el = NULL; @@ -250,17 +263,20 @@ enum cmix_error key_exchange_initiator(struct CMixContext const* ctx, GroupEleme enum cmix_error post_process(struct CMixContext* ctx, char* r_out, char* m_out, char const* r_epirs, char const* m_epirs, size_t index) { GroupElement x = ctx->api.array_to_element(r_epirs, get_group_element_array_size(ctx), true); GroupElement D = ctx->api.get_decryption_share(x, ctx->keypair.sec); - element_to_buffer(ctx, r_out, D); + //element_to_buffer(ctx, r_out, D); GroupElement msg = ctx->api.array_to_element(m_epirs, get_group_element_array_size(ctx), true); GroupElement pirs = ctx->api.multiply(D, msg, true); element_to_buffer(ctx, m_out, pirs); + GroupElement new_r = ctx->api.multiply(x, D, true); + element_to_buffer(ctx, r_out, new_r); ctx->pirs[index] = pirs; // this is not always usable as only the last node will be able to use this effectively, but we store it anyways. ctx->api.free_group_element(x); ctx->api.free_group_element(D); ctx->api.free_group_element(msg); + ctx->api.free_group_element(new_r); return no_error; } @@ -280,3 +296,36 @@ enum cmix_error blind_message(struct CMixContext const* ctx, char* m_out, char c return no_error; } + +enum cmix_error swap_k_for_r(struct CMixContext const* ctx, char* out_buffer, char const* message, GroupElement const key, size_t index) { + size_t len = get_group_element_array_size(ctx); + + GroupElement mes = ctx->api.array_to_element(message, len, false); + GroupElement inv_key = ctx->api.invert(key); + + GroupElement unblinded = ctx->api.multiply(mes, inv_key, false); + GroupElement blinded = ctx->api.multiply(unblinded, ctx->r[index], false); + + element_to_buffer(ctx, out_buffer, blinded); + ctx->api.free_group_element(mes); + ctx->api.free_group_element(inv_key); + ctx->api.free_group_element(unblinded); + ctx->api.free_group_element(blinded); + + return no_error; +} + +enum cmix_error remove_r_and_s(struct CMixContext const* ctx, char* out_buffer, char const* message, size_t index) { + size_t len = get_group_element_array_size(ctx); + + GroupElement mes = ctx->api.array_to_element(message, len, false); + GroupElement inv_pirs = ctx->api.invert(ctx->pirs[index]); + + GroupElement mult = ctx->api.multiply(mes, inv_pirs, false); + + element_to_buffer(ctx, out_buffer, mult); + + ctx->api.free_group_element(mes); + ctx->api.free_group_element(inv_pirs); + ctx->api.free_group_element(mult); +} diff --git a/libcmix/cmix.h b/libcmix/cmix.h index 33b99d2..ba0b826 100644 --- a/libcmix/cmix.h +++ b/libcmix/cmix.h @@ -78,9 +78,12 @@ struct CMixContext { GroupElement* s; unsigned int* permutation; GroupElement* pirs; - GroupElement* messages; }; +#ifndef NDEBUG +void element_to_buffer(struct CMixContext const* ctx, char* buffer, GroupElement const element); +#endif + struct CMixContext initialize_cmix_context(struct Api api); void deinitialize(struct CMixContext* ctx); @@ -95,7 +98,7 @@ enum cmix_error start_mix(struct CMixContext* ctx, size_t nr_participants); enum cmix_error initialize_mix_randomness(struct CMixContext* ctx); -enum cmix_error generate_random_message(struct CMixContext* ctx, size_t index); +enum cmix_error generate_random_message(struct CMixContext* ctx, char* buffer); size_t get_group_element_array_size(struct CMixContext const* ctx); @@ -105,7 +108,9 @@ enum cmix_error encrypt_r(struct CMixContext const* ctx, char* random_buffer, ch enum cmix_error encrypt_r_and_multiply(struct CMixContext const* ctx, char* random_buffer, char* message_buffer, char const* random_element, char const* message_element, size_t index); -enum cmix_error multiply_s(struct CMixContext const* ctx, char* r_out_buffer, char* m_out_buffer, char const* r_in_buffer, char const* m_in_buffer, size_t index); +enum cmix_error multiply_encrypted_s(struct CMixContext const* ctx, char* r_out_buffer, char* m_out_buffer, char const* r_in_buffer, char const* m_in_buffer, size_t index); + +enum cmix_error multiply_s(struct CMixContext const* ctx, char* out_buffer, char const* message, size_t index); enum cmix_error get_key_exchange_value(struct CMixContext const* ctx, char* buffer, GroupElement priv_element); @@ -119,6 +124,14 @@ enum cmix_error post_process(struct CMixContext* ctx, char* r_out, char* m_out, enum cmix_error blind_message(struct CMixContext const* ctx, char* m_out, char const* message, GroupElement const* keys, size_t const nr_nodes); +enum cmix_error enqueue_message(struct CMixContext* ctx, char const* message, size_t index); + +enum cmix_error enqueue_random_message(struct CMixContext* ctx, size_t index); + +enum cmix_error swap_k_for_r(struct CMixContext const* ctx, char* out_buffer, char const* message, GroupElement const key, size_t index); + +enum cmix_error remove_r_and_s(struct CMixContext const* ctx, char* out_buffer, char const* message, size_t index); + #ifdef __cplusplus } // extern "C" #endif |