Module ext_builders 

Python bindings for X.509 extension DER value builders.

Registers the synta.ext submodule with low-level DER-encoding helpers for the most common X.509 v3 extension values. Each function returns the raw DER bytes of the extension’s extnValue — the content inside the OCTET STRING wrapper.

Key identifier method constants

Pass these to subject_key_identifier and authority_key_identifier as the method argument:

Constant	Value	Specification
KEYID_RFC5280	0	SHA-1 of BIT STRING value of subjectPublicKey (RFC 5280 §4.2.1.2)
KEYID_RFC7093M1	1	SHA-256 of BIT STRING value, truncated to 160 bits (RFC 7093 §2 m1)
KEYID_RFC7093M2	2	SHA-384 of BIT STRING value, truncated to 160 bits (RFC 7093 §2 m2)
KEYID_RFC7093M3	3	SHA-512 of BIT STRING value, truncated to 160 bits (RFC 7093 §2 m3)
KEYID_RFC7093M4	4	SHA-256 of full SubjectPublicKeyInfo DER (RFC 7093 §2 m4)

Key usage bitmask constants

KU_* constants are ready-to-OR bitmasks for key_usage:

Constant	Mask	Named bit (RFC 5280 §4.2.1.3)
KU_DIGITAL_SIGNATURE	0x001	digitalSignature
KU_NON_REPUDIATION	0x002	contentCommitment
KU_KEY_ENCIPHERMENT	0x004	keyEncipherment
KU_DATA_ENCIPHERMENT	0x008	dataEncipherment
KU_KEY_AGREEMENT	0x010	keyAgreement
KU_KEY_CERT_SIGN	0x020	keyCertSign
KU_CRL_SIGN	0x040	cRLSign
KU_ENCIPHER_ONLY	0x080	encipherOnly
KU_DECIPHER_ONLY	0x100	decipherOnly

Fluent builder classes

Four builder classes accumulate entries and produce DER on .build():

Class	Short alias	Extension	OID
SubjectAlternativeNameBuilder	SAN	Subject Alternative Name	2.5.29.17
AuthorityInformationAccessBuilder	AIA	Authority Information Access	1.3.6.1.5.5.7.1.1
ExtendedKeyUsageBuilder	EKU	Extended Key Usage	2.5.29.37
NameConstraintsBuilder	NC	Name Constraints	2.5.29.30

Structs

PyAuthorityInformationAccessBuilder

Fluent builder for an AuthorityInfoAccessSyntax extension value (OID 1.3.6.1.5.5.7.1.1, Authority Information Access, RFC 5280 §4.2.2.1).

PyCRLDistributionPointsBuilder

Fluent builder for a CRLDistributionPoints extension value (OID 2.5.29.31).

PyCertificatePoliciesBuilder

Fluent builder for a CertificatePolicies extension value (OID 2.5.29.32, RFC 5280 §4.2.1.4).

PyExtendedKeyUsageBuilder

Fluent builder for an ExtKeyUsageSyntax extension value (OID 2.5.29.37, Extended Key Usage, RFC 5280 §4.2.1.12).

PyIssuerAlternativeNameBuilder

Fluent builder for an IssuerAltName extension value (OID 2.5.29.18).

PyIssuingDistributionPointBuilder

Fluent builder for an IssuingDistributionPoint extension value (OID 2.5.29.28, RFC 5280 §5.2.5).

PyNameConstraintsBuilder

Fluent builder for a NameConstraints extension value (OID 2.5.29.30, RFC 5280 §4.2.1.10).

PySubjectAlternativeNameBuilder

Fluent builder for a SubjectAltName extension value (OID 2.5.29.17).

Constants

KEYID_RFC5280

RFC 5280 §4.2.1.2: SHA-1 of the BIT STRING value of subjectPublicKey.

KEYID_RFC7093M1

RFC 7093 §2 method 1: SHA-256 of BIT STRING value, truncated to 160 bits.

KEYID_RFC7093M2

RFC 7093 §2 method 2: SHA-384 of BIT STRING value, truncated to 160 bits.

KEYID_RFC7093M3

RFC 7093 §2 method 3: SHA-512 of BIT STRING value, truncated to 160 bits.

KEYID_RFC7093M4

RFC 7093 §2 method 4: SHA-256 of the full SubjectPublicKeyInfo DER encoding.

KU_CRL_SIGN

cRLSign (bit 6) — RFC 5280 §4.2.1.3.

KU_DATA_ENCIPHERMENT

dataEncipherment (bit 3) — RFC 5280 §4.2.1.3.

KU_DECIPHER_ONLY

decipherOnly (bit 8) — RFC 5280 §4.2.1.3; only meaningful when keyAgreement is set.

KU_DIGITAL_SIGNATURE

digitalSignature (bit 0) — RFC 5280 §4.2.1.3.

KU_ENCIPHER_ONLY

encipherOnly (bit 7) — RFC 5280 §4.2.1.3; only meaningful when keyAgreement is set.

KU_KEY_AGREEMENT

keyAgreement (bit 4) — RFC 5280 §4.2.1.3.

KU_KEY_CERT_SIGN

keyCertSign (bit 5) — RFC 5280 §4.2.1.3.

KU_KEY_ENCIPHERMENT

keyEncipherment (bit 2) — RFC 5280 §4.2.1.3.

KU_NON_REPUDIATION

contentCommitment / nonRepudiation (bit 1) — RFC 5280 §4.2.1.3.

Functions

register_ext_module

Register the synta.ext submodule.