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/* Copyright 2016 OpenMarket Ltd
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef OLM_OUTBOUND_GROUP_SESSION_H_
#define OLM_OUTBOUND_GROUP_SESSION_H_
#include <stddef.h>
#include <stdint.h>
#ifdef __cplusplus
extern "C" {
#endif
typedef struct OlmOutboundGroupSession OlmOutboundGroupSession;
/** get the size of an outbound group session, in bytes. */
size_t olm_outbound_group_session_size();
/**
* Initialise an outbound group session object using the supplied memory
* The supplied memory should be at least olm_outbound_group_session_size()
* bytes.
*/
OlmOutboundGroupSession * olm_outbound_group_session(
void *memory
);
/**
* A null terminated string describing the most recent error to happen to a
* group session */
const char *olm_outbound_group_session_last_error(
const OlmOutboundGroupSession *session
);
/** Clears the memory used to back this group session */
size_t olm_clear_outbound_group_session(
OlmOutboundGroupSession *session
);
/** Returns the number of bytes needed to store an outbound group session */
size_t olm_pickle_outbound_group_session_length(
const OlmOutboundGroupSession *session
);
/**
* Stores a group session as a base64 string. Encrypts the session using the
* supplied key. Returns the length of the session on success.
*
* Returns olm_error() on failure. If the pickle output buffer
* is smaller than olm_pickle_outbound_group_session_length() then
* olm_outbound_group_session_last_error() will be "OUTPUT_BUFFER_TOO_SMALL"
*/
size_t olm_pickle_outbound_group_session(
OlmOutboundGroupSession *session,
void const * key, size_t key_length,
void * pickled, size_t pickled_length
);
/**
* Loads a group session from a pickled base64 string. Decrypts the session
* using the supplied key.
*
* Returns olm_error() on failure. If the key doesn't match the one used to
* encrypt the account then olm_outbound_group_session_last_error() will be
* "BAD_ACCOUNT_KEY". If the base64 couldn't be decoded then
* olm_outbound_group_session_last_error() will be "INVALID_BASE64". The input
* pickled buffer is destroyed
*/
size_t olm_unpickle_outbound_group_session(
OlmOutboundGroupSession *session,
void const * key, size_t key_length,
void * pickled, size_t pickled_length
);
/** The number of random bytes needed to create an outbound group session */
size_t olm_init_outbound_group_session_random_length(
const OlmOutboundGroupSession *session
);
/**
* Start a new outbound group session. Returns olm_error() on failure. On
* failure last_error will be set with an error code. The last_error will be
* NOT_ENOUGH_RANDOM if the number of random bytes was too small.
*/
size_t olm_init_outbound_group_session(
OlmOutboundGroupSession *session,
uint8_t *random, size_t random_length
);
/**
* The number of bytes that will be created by encrypting a message
*/
size_t olm_group_encrypt_message_length(
OlmOutboundGroupSession *session,
size_t plaintext_length
);
/**
* Encrypt some plain-text. Returns the length of the encrypted message or
* olm_error() on failure. On failure last_error will be set with an
* error code. The last_error will be OUTPUT_BUFFER_TOO_SMALL if the output
* buffer is too small.
*/
size_t olm_group_encrypt(
OlmOutboundGroupSession *session,
uint8_t const * plaintext, size_t plaintext_length,
uint8_t * message, size_t message_length
);
/**
* Get the number of bytes returned by olm_outbound_group_session_id()
*/
size_t olm_outbound_group_session_id_length(
const OlmOutboundGroupSession *session
);
/**
* Get a base64-encoded identifier for this session.
*
* Returns the length of the session id on success or olm_error() on
* failure. On failure last_error will be set with an error code. The
* last_error will be OUTPUT_BUFFER_TOO_SMALL if the id buffer was too
* small.
*/
size_t olm_outbound_group_session_id(
OlmOutboundGroupSession *session,
uint8_t * id, size_t id_length
);
/**
* Get the current message index for this session.
*
* Each message is sent with an increasing index; this returns the index for
* the next message.
*/
uint32_t olm_outbound_group_session_message_index(
OlmOutboundGroupSession *session
);
/**
* Get the number of bytes returned by olm_outbound_group_session_key()
*/
size_t olm_outbound_group_session_key_length(
const OlmOutboundGroupSession *session
);
/**
* Get the base64-encoded current ratchet key for this session.
*
* Each message is sent with a different ratchet key. This function returns the
* ratchet key that will be used for the next message.
*
* Returns the length of the ratchet key on success or olm_error() on
* failure. On failure last_error will be set with an error code. The
* last_error will be OUTPUT_BUFFER_TOO_SMALL if the buffer was too small.
*/
size_t olm_outbound_group_session_key(
OlmOutboundGroupSession *session,
uint8_t * key, size_t key_length
);
#ifdef __cplusplus
} // extern "C"
#endif
#endif /* OLM_OUTBOUND_GROUP_SESSION_H_ */
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