A Usable, Secure Communications Protocol: Client-Side TLS - Implementing SSL/TLS Using Cryptography and PKI - page 314

*/
typedef enum
{
close_notify = 0,
unexpected_message = 10,
bad_record_mac = 20,
decryption_failed = 21,
record_overflow = 22,
decompression_failure = 30,
handshake_failure = 40,
bad_certificate = 42,
unsupported_certificate = 43,
certificate_revoked = 44,
certificate_expired = 45,
certificate_unknown = 46,
illegal_parameter = 47,
unknown_ca = 48,
access_denied = 49,
decode_error = 50,
decrypt_error = 51,
export_restriction = 60,
protocol_version = 70,
insufficient_security = 71,
internal_error = 80,
user_canceled = 90,
no_renegotiation = 100
}
AlertDescription;
typedef struct
{
unsigned char level;
unsigned char description;
}
Alert;
/**
* Each packet to be encrypted is first inserted into one of these structures.
*/
typedef struct
{
unsigned char type;
ProtocolVersion version;
unsigned short length;
}
TLSPlaintext;
There are four types of TLS messages defi ned: handshake messages, alerts,
data, and “change cipher spec,” which is technically a handshake message, but