Enum CasError 

pub enum CasError {
    InvalidKey,
    InvalidNonce,
    InvalidSignature,
    InvalidInput,
    InvalidPemKey,
    InvalidParameters,
    EncryptionFailed,
    DecryptionFailed,
    SigningFailed,
    KeyGenerationFailed,
    PasswordHashingFailed,
    CompressionFailed,
}

The unified error type returned by all fallible cas-lib operations.

Every cryptographic operation that can fail returns CasResult instead of panicking. This is important for FFI consumers: a panic unwinding across the FFI boundary is undefined behavior and typically aborts the host process. A malformed key, a tampered ciphertext, or a failed authentication tag are all recoverable conditions and are reported through this enum.

ABI stability contract

The downstream FFI binding crates (cas-core-lib, cas-typescript-sdk) surface each variant to their callers as the stable numeric code returned by CasError::error_code. Those numbers are part of the ABI contract with every consumer SDK, so this enum is append-only:

• Never remove, rename, or renumber an existing variant.
• Add new variants only at the end, and give them the next free code in CasError::error_code.

The error_code_contract_is_stable test in this module pins the mapping so an accidental reorder or removal fails CI here rather than silently breaking a consumer’s error handling.

Variants

InvalidKey

A provided key had an invalid length or could not be parsed.

InvalidNonce

A provided nonce/IV had an invalid length.

InvalidSignature

A provided signature had an invalid length or could not be parsed.

InvalidInput

Input bytes could not be decoded into the expected type.

InvalidPemKey

PEM/DER decoding or encoding of a key failed.

InvalidParameters

Invalid algorithm parameters were supplied (e.g. an RSA key size that is too small, or out-of-range password-hashing parameters).

EncryptionFailed

AEAD encryption failed.

DecryptionFailed

AEAD decryption failed or the authentication tag did not verify.

SigningFailed

A signing operation failed.

KeyGenerationFailed

Key generation failed.

PasswordHashingFailed

Password hashing or verification setup failed.

CompressionFailed

Compression or decompression failed.

Implementations

impl CasError

pub fn error_code(&self) -> i32

Maps this error to the stable numeric code surfaced through the FFI by the downstream binding crates. 0 is reserved for success and is never returned here.

These values are part of the ABI contract described on CasError; see the type-level documentation before changing them.

Trait Implementations

impl Clone for CasError

fn clone(&self) -> CasError

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for CasError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for CasError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for CasError

impl Error for CasError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl PartialEq for CasError

fn eq(&self, other: &CasError) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for CasError