diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/olm/session.hh | 46 |
1 files changed, 44 insertions, 2 deletions
diff --git a/include/olm/session.hh b/include/olm/session.hh index 993a8da..b21b0aa 100644 --- a/include/olm/session.hh +++ b/include/olm/session.hh @@ -39,8 +39,13 @@ struct Session { Curve25519PublicKey alice_base_key; Curve25519PublicKey bob_one_time_key; + /** The number of random bytes that are needed to create a new outbound + * session. This will be 64 bytes since two ephemeral keys are needed. */ std::size_t new_outbound_session_random_length(); + /** Start a new outbound session. Returns std::size_t(-1) 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. */ std::size_t new_outbound_session( Account const & local_account, Curve25519PublicKey const & identity_key, @@ -48,42 +53,79 @@ struct Session { std::uint8_t const * random, std::size_t random_length ); + /** Start a new inbound session from a pre-key message. + * Returns std::size_t(-1) on failure. On failure last_error will be set + * with an error code. The last_error will be BAD_MESSAGE_FORMAT if + * the message headers could not be decoded. */ std::size_t new_inbound_session( Account & local_account, Curve25519PublicKey const * their_identity_key, - std::uint8_t const * one_time_key_message, std::size_t message_length + std::uint8_t const * pre_key_message, std::size_t message_length ); + /** The number of bytes written by session_id() */ std::size_t session_id_length(); + /** An identifier for this session. Generated by hashing the public keys + * used to create the session. Returns the length of the session id on + * success or std::size_t(-1) 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. */ std::size_t session_id( std::uint8_t * id, std::size_t id_length ); + /** True if this session can be used to decode an inbound pre-key message. + * This can be used to test whether a pre-key message should be decoded + * with an existing session or if a new session will need to be created. + * Returns true if the session is the same. Returns false if either the + * session does not match or the pre-key message could not be decoded. + */ bool matches_inbound_session( Curve25519PublicKey const * their_identity_key, - std::uint8_t const * one_time_key_message, std::size_t message_length + std::uint8_t const * pre_key_message, std::size_t message_length ); + /** Whether the next message will be a pre-key message or a normal message. + * An outbound session will send pre-key messages until it receives a + * message with a ratchet key. */ MessageType encrypt_message_type(); std::size_t encrypt_message_length( std::size_t plaintext_length ); + /** The number of bytes of random data the encrypt method will need to + * encrypt a message. This will be 32 bytes if the session needs to + * generate a new ephemeral key, or will be 0 bytes otherwise. */ std::size_t encrypt_random_length(); + /** Encrypt some plain-text. Returns the length of the encrypted message + * or std::size_t(-1) 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 is too small. The last_error will be + * OUTPUT_BUFFER_TOO_SMALL if the output buffer is too small. */ std::size_t encrypt( std::uint8_t const * plaintext, std::size_t plaintext_length, std::uint8_t const * random, std::size_t random_length, std::uint8_t * message, std::size_t message_length ); + /** An upper bound on the number of bytes of plain-text the decrypt method + * will write for a given input message length. */ std::size_t decrypt_max_plaintext_length( MessageType message_type, std::uint8_t const * message, std::size_t message_length ); + /** Decrypt a message. Returns the length of the decrypted plain-text or + * std::size_t(-1) on failure. On failure last_error will be set with an + * error code. The last_error will be OUTPUT_BUFFER_TOO_SMALL if the + * plain-text buffer is too small. The last_error will be + * BAD_MESSAGE_VERSION if the message was encrypted with an unsupported + * version of the protocol. The last_error will be BAD_MESSAGE_FORMAT if + * the message headers could not be decoded. The last_error will be + * BAD_MESSAGE_MAC if the message could not be verified */ std::size_t decrypt( MessageType message_type, std::uint8_t const * message, std::size_t message_length, |