Exceptions¶

All pybergshamra exceptions inherit from BergshamraError, which itself inherits from Python’s built-in Exception.

exception BergshamraError¶

Base exception for all pybergshamra errors. Catch this to handle any error from the library.

import pybergshamra

try:
    pybergshamra.verify(ctx, xml)
except pybergshamra.BergshamraError as e:
    print(f"Something went wrong: {e}")

exception XmlError¶

Raised when XML parsing or structural validation fails – for example, malformed XML input or a missing required element.

import pybergshamra

try:
    pybergshamra.verify(ctx, "<not valid xml")
except pybergshamra.XmlError as e:
    print(f"XML error: {e}")

exception CryptoError¶

Raised for cryptographic operation failures, including invalid signatures and digest mismatches detected during signing or verification setup.

import pybergshamra

try:
    pybergshamra.sign(ctx, template_xml)
except pybergshamra.CryptoError as e:
    print(f"Crypto error: {e}")

Note

Signature verification via verify() returns a VerifyResult with is_valid = False rather than raising CryptoError. This exception is raised only for unexpected cryptographic failures during the operation.

exception KeyLoadError¶

Raised when a key cannot be loaded – for example, invalid PEM data, wrong password, or unsupported key format.

import pybergshamra

try:
    key = pybergshamra.load_rsa_private_pem(b"not a pem")
except pybergshamra.KeyLoadError as e:
    print(f"Key load failed: {e}")

exception AlgorithmError¶

Raised when an unsupported or unrecognized algorithm URI is used.

import pybergshamra

try:
    pybergshamra.digest("http://example.com/not-an-algorithm", b"data")
except pybergshamra.AlgorithmError as e:
    print(f"Unknown algorithm: {e}")

exception EncryptionError¶

Raised when an encryption or decryption operation fails – for example, missing key material, wrong key type, or corrupt ciphertext.

import pybergshamra

try:
    pybergshamra.decrypt(ctx, encrypted_xml)
except pybergshamra.EncryptionError as e:
    print(f"Decryption failed: {e}")

exception CertificateError¶

Raised when X.509 certificate validation fails – for example, expired certificate, untrusted issuer, or broken chain.

import pybergshamra

try:
    pybergshamra.validate_cert_chain(
        leaf_der, trusted_certs=[ca_der]
    )
except pybergshamra.CertificateError as e:
    print(f"Certificate invalid: {e}")

Exception hierarchy¶

Exception
└── BergshamraError
    ├── XmlError
    ├── CryptoError
    ├── KeyLoadError
    ├── AlgorithmError
    ├── EncryptionError
    └── CertificateError