Module cgo

Available on crate feature counter-galois-onion only.

Implementation for Counter Galois Onion (CGO) relay cell encryption

CGO is an improved approach for encrypting relay cells, with better support for tagging resistance, better forward secrecy, and other improvements. It is described in a paper by Degabriele, Melloni, Münch, and Stam, and specified in proposal 359.

CGO is based on a construction called “UIV+”, which provides the “robust pseudorandom permutation” security definition. Notably, encryption with UIV+ is non-malleable (and hence tagging resistant), whereas decryption with UIV+ is malleable (and hence not tagging resistant).

Modules

bench_utilsbench

Benchmark utilities for the cgo module.

et 🔒

Define a tweakable block cipher.

prf 🔒

Define a tweakable pseudorandom stream generator.

uiv 🔒

Define the UIV+ tweakable wide-block cipher.

Structs

ClientInbound

An instance of CGO used for inbound client encryption.

ClientOutbound

An instance of CGO used for outbound client encryption.

CryptState 🔒

State of a single direction of a CGO layer, at the client or at a relay.

CryptStatePair

A set of cryptographic information as shared by the client and a single relay, and

RelayInbound

An instance of CGO used for inbound (towards the client) relay encryption.

RelayOutbound

An instance of CGO used for outbound (away from the client) relay encryption.

Constants

BLK_LEN 🔒

Block length. Used by various types.

CGO_AD_LEN 🔒

Size of CGO additional data, in bytes.

CGO_PAYLOAD_LEN 🔒

Size of CGO payload, in bytes.

CGO_TAG_LEN 🔒

Size of CGO tag, in bytes.

HLEN_UIV 🔒

Size of the “H” tweak passed to the UIV+ construction.

Traits

BlkCipher

Helper trait to define the features we need from a block cipher, and make our “where” declarations smaller.

BlkCipherDec

Helper trait to define the features we need from a block cipher, and make our “where” declarations smaller.

BlkCipherEnc

Helper trait to define the features we need from a block cipher, and make our “where” declarations smaller.

Functions

first_block 🔒

Helper: return the first BLK_LEN bytes of a slice as an array.

xor_into 🔒

Xor all bytes from input into output.

Type Aliases

Block 🔒

A single block. Used as input to various functions.

BlockLen 🔒

Block length as a typenum; used to parameterize some types that use ArrayLen.