Table of Contents

Class AlertDescription

Namespace
Org.BouncyCastle.Tls
Assembly
BouncyCastle.Cryptography.dll

RFC 5246 7.2.

public abstract class AlertDescription
Inheritance
AlertDescription
Inherited Members

Fields

access_denied

A valid certificate was received, but when access control was applied, the sender decided not to proceed with negotiation.

public const short access_denied = 49

Field Value

short

Remarks

This message is always fatal.

bad_certificate

A certificate was corrupt, contained signatures that did not verify correctly, etc.

public const short bad_certificate = 42

Field Value

short

bad_certificate_hash_value

This alert is sent by servers when a certificate hash does not match a client provided certificate_hash.

public const short bad_certificate_hash_value = 114

Field Value

short

Remarks

This message is always fatal.

bad_certificate_status_response

This alert is sent by clients that receive an invalid certificate status response (see Section 3.6 ).

public const short bad_certificate_status_response = 113

Field Value

short

Remarks

This message is always fatal.

bad_record_mac

This alert is returned if a record is received with an incorrect MAC.

public const short bad_record_mac = 20

Field Value

short

Remarks

This alert also MUST be returned if an alert is sent because a TLSCiphertext decrypted in an invalid way: either it wasn't an even multiple of the block length, or its padding values, when checked, weren't correct. This message is always fatal and should never be observed in communication between proper implementations (except when messages were corrupted in the network).

certificate_expired

A certificate has expired or is not currently valid.

public const short certificate_expired = 45

Field Value

short

certificate_required

Sent by servers when a client certificate is desired but none was provided by the client.

public const short certificate_required = 116

Field Value

short

certificate_revoked

A certificate was revoked by its signer.

public const short certificate_revoked = 44

Field Value

short

certificate_unknown

Some other (unspecified) issue arose in processing the certificate, rendering it unacceptable.

public const short certificate_unknown = 46

Field Value

short

certificate_unobtainable

This alert is sent by servers who are unable to retrieve a certificate chain from the URL supplied by the client(see Section 3.3).

public const short certificate_unobtainable = 111

Field Value

short

Remarks

This message MAY be fatal - for example if client authentication is required by the server for the handshake to continue and the server is unable to retrieve the certificate chain, it may send a fatal alert.

close_notify

This message notifies the recipient that the sender will not send any more messages on this connection.

public const short close_notify = 0

Field Value

short

Remarks

Note that as of TLS 1.1, failure to properly close a connection no longer requires that a session not be resumed. This is a change from TLS 1.0 ("The session becomes unresumable if any connection is terminated without proper close_notify messages with level equal to warning.") to conform with widespread implementation practice.

decode_error

A message could not be decoded because some field was out of the specified range or the length of the message was incorrect.

public const short decode_error = 50

Field Value

short

Remarks

This message is always fatal and should never be observed in communication between proper implementations (except when messages were corrupted in the network).

decompression_failure

The decompression function received improper input (e.g., data that would expand to excessive length).

public const short decompression_failure = 30

Field Value

short

Remarks

This message is always fatal and should never be observed in communication between proper implementations.

decrypt_error

A handshake cryptographic operation failed, including being unable to correctly verify a signature or validate a Finished message.

public const short decrypt_error = 51

Field Value

short

Remarks

This message is always fatal.

decryption_failed 

public const short decryption_failed = 21

Field Value

short

Remarks

This alert was used in some earlier versions of TLS, and may have permitted certain attacks against the CBC mode [CBCATT]. It MUST NOT be sent by compliant implementations.

export_restriction 

public const short export_restriction = 60

Field Value

short

Remarks

This alert was used in some earlier versions of TLS. It MUST NOT be sent by compliant implementations.

handshake_failure

Reception of a handshake_failure alert message indicates that the sender was unable to negotiate an acceptable set of security parameters given the options available.

public const short handshake_failure = 40

Field Value

short

Remarks

This is a fatal error.

illegal_parameter

A field in the handshake was out of range or inconsistent with other fields.

public const short illegal_parameter = 47

Field Value

short

Remarks

This message is always fatal.

inappropriate_fallback

If TLS_FALLBACK_SCSV appears in ClientHello.cipher_suites and the highest protocol version supported by the server is higher than the version indicated in ClientHello.client_version, the server MUST respond with a fatal inappropriate_fallback alert[..].

public const short inappropriate_fallback = 86

Field Value

short

insufficient_security

Returned instead of handshake_failure when a negotiation has failed specifically because the server requires ciphers more secure than those supported by the client.

public const short insufficient_security = 71

Field Value

short

Remarks

This message is always fatal.

internal_error

An internal error unrelated to the peer or the correctness of the protocol (such as a memory allocation failure) makes it impossible to continue.

public const short internal_error = 80

Field Value

short

Remarks

This message is always fatal.

missing_extension

Sent by endpoints that receive a handshake message not containing an extension that is mandatory to send for the offered TLS version or other negotiated parameters.

public const short missing_extension = 109

Field Value

short

no_application_protocol

In the event that the server supports no protocols that the client advertises, then the server SHALL respond with a fatal "no_application_protocol" alert.

public const short no_application_protocol = 120

Field Value

short

no_certificate 

public const short no_certificate = 41

Field Value

short

Remarks

This alert was used in SSLv3 but not any version of TLS. It MUST NOT be sent by compliant implementations.

no_renegotiation

Sent by the client in response to a hello request or by the server in response to a client hello after initial handshaking.

public const short no_renegotiation = 100

Field Value

short

Remarks

Either of these would normally lead to renegotiation; when that is not appropriate, the recipient should respond with this alert. At that point, the original requester can decide whether to proceed with the connection. One case where this would be appropriate is where a server has spawned a process to satisfy a request; the process might receive security parameters (key length, authentication, etc.) at startup, and it might be difficult to communicate changes to these parameters after that point. This message is always a warning.

protocol_version

The protocol version the client has attempted to negotiate is recognized but not supported.

public const short protocol_version = 70

Field Value

short

Remarks

(For example, old protocol versions might be avoided for security reasons.) This message is always fatal.

record_overflow

A TLSCiphertext record was received that had a length more than 2^14+2048 bytes, or a record decrypted to a TLSCompressed record with more than 2^14+1024 bytes.

public const short record_overflow = 22

Field Value

short

Remarks

This message is always fatal and should never be observed in communication between proper implementations (except when messages were corrupted in the network).

unexpected_message

An inappropriate message was received.

public const short unexpected_message = 10

Field Value

short

Remarks

This alert is always fatal and should never be observed in communication between proper implementations.

unknown_ca

A valid certificate chain or partial chain was received, but the certificate was not accepted because the CA certificate could not be located or couldn't be matched with a known, trusted CA.

public const short unknown_ca = 48

Field Value

short

Remarks

This message is always fatal.

unknown_psk_identity

If the server does not recognize the PSK identity, it MAY respond with an "unknown_psk_identity" alert message.

public const short unknown_psk_identity = 115

Field Value

short

unrecognized_name

This alert is sent by servers that receive a server_name extension request, but do not recognize the server name.

public const short unrecognized_name = 112

Field Value

short

Remarks

This message MAY be fatal.

unsupported_certificate

A certificate was of an unsupported type.

public const short unsupported_certificate = 43

Field Value

short

unsupported_extension

Sent by clients that receive an extended server hello containing an extension that they did not put in the corresponding client hello.

public const short unsupported_extension = 110

Field Value

short

Remarks

This message is always fatal.

user_canceled

This handshake is being canceled for some reason unrelated to a protocol failure.

public const short user_canceled = 90

Field Value

short

Remarks

If the user cancels an operation after the handshake is complete, just closing the connection by sending a close_notify is more appropriate. This alert should be followed by a close_notify. This message is generally a warning.

Methods

GetName(short) 

public static string GetName(short alertDescription)

Parameters

alertDescription short

Returns

string

GetText(short) 

public static string GetText(short alertDescription)

Parameters

alertDescription short

Returns

string