echspec

echspec is a conformance testing tool for ECH implementation.

• https://datatracker.ietf.org/doc/html/draft-ietf-tls-esni-18

Initial Setup

You can install with:

$ gem install specific_install

$ gem specific_install git@github.com:thekuwayama/echspec.git

Usage

$ echspec --help
Usage: echspec [OPTIONS] <HOSTNAME>
    -f, --file FILE                  path to ECHConfigs PEM file       (default resolve ECHConfigs via DNS)
    -p, --port VALUE                 server port number                (default 443)
    -n, --not-force-compliant-hpke   not force compliant ECHConfig HPKE cipher suite
    -v, --verbose                    verbose mode; prints message stack if raised an error
    -s, --sections SECTIONS          sections to test; by the default, test all sections

You can run it the following:

$ echspec crypto.cloudflare.com
TLS Encrypted Client Hello Server
        ✔ MUST implement the following HPKE cipher suite: KEM: DHKEM(X25519, HKDF-SHA256), KDF: HKDF-SHA256 and AEAD: AES-128-GCM. [9]
        ✔ MUST abort with an "illegal_parameter" alert, if EncodedClientHelloInner is padded with non-zero values. [5.1-9]
        ✔ MUST abort with an "illegal_parameter" alert, if any referenced extension is missing in ClientHelloOuter. [5.1-10]
        ✔ MUST abort with an "illegal_parameter" alert, if any extension is referenced in OuterExtensions more than once. [5.1-10]
        ✔ MUST abort with an "illegal_parameter" alert, if "encrypted_client_hello" is referenced in OuterExtensions. [5.1-10]
        ✔ MUST abort with an "illegal_parameter" alert, if the extensions in ClientHelloOuter corresponding to those in OuterExtensions do not occur in the same order. [5.1-10]
        ✔ MUST abort with an "illegal_parameter" alert, if ECHClientHello.type is not a valid ECHClientHelloType in ClientHelloInner. [7-5]
        ✔ MUST abort with an "illegal_parameter" alert, if ECHClientHello.type is not a valid ECHClientHelloType in ClientHelloOuter. [7-5]
        ✔ MUST abort with an "illegal_parameter" alert, if ClientHelloInner offers TLS 1.2 or below. [7.1-11]
        ✔ MUST include the "encrypted_client_hello" extension in its EncryptedExtensions with the "retry_configs" field set to one or more ECHConfig. [7.1-14.2.1]
        ✔ MUST abort with a "missing_extension" alert, if 2nd ClientHelloOuter does not contains the "encrypted_client_hello" extension. [7.1.1-2]
        ✔ MUST abort with an "illegal_parameter" alert, if 2nd ClientHelloOuter "encrypted_client_hello" enc is empty. [7.1.1-2]
        ✔ MUST abort with a "decrypt_error" alert, if fails to decrypt 2nd ClientHelloOuter. [7.1.1-5]

By default, echspec retrieves ECHConfigs via HTTPS records. By using the -f, --file FILE option, you can specify an ECHConfig pem file. If you need to test the server on localhost, you can run it the following:

$ echspec -f fixtures/echconfigs.pem -p 4433 localhost

By default, echspec uses the following HPKE cipher suite

• KEM
  • DHKEM(X25519, HKDF-SHA256)
• KDF
  • HKDF-SHA256
• AEAD
  • AES-128-GCM

By using the -n, --not-force-compliant-hpke, you can not enforce the HPKE cipher suite.

$ echspec -f fixtures/echconfigs.pem -p 4433 -n localhost

If you specify the SECTIONS, you can run only SECTIONS the following:

$ echspec -f fixtures/echconfigs.pem -p 4433 -n -s 7.1.1-2,7.1.1-5 localhost
TLS Encrypted Client Hello Server
        ✔ MUST abort with a "missing_extension" alert, if 2nd ClientHelloOuter does not contains the "encrypted_client_hello" extension. [7.1.1-2]
        ✔ MUST abort with an "illegal_parameter" alert, if 2nd ClientHelloOuter "encrypted_client_hello" enc is empty. [7.1.1-2]
        ✔ MUST abort with a "decrypt_error" alert, if fails to decrypt 2nd ClientHelloOuter. [7.1.1-5]

License

echspec is available as open source under the terms of the MIT License.