Twofish-TS

This is a decently-performant, memory-efficient TypeScript implementation of the Twofish block encryption algorithm, validated with the test vectors from https://www.schneier.com/wp-content/uploads/2015/12/ecb_ival.txt

The module has the following exports:

export declare type Session;
export declare function makeSession(key: Uint8Array): Session;
export declare function encrypt(input: Uint8Array, io: number, output: Uint8Array, oo: number, session: Session): void;
export declare function decrypt(input: Uint8Array, io: number, output: Uint8Array, oo: number, session: Session): void;

makeSession uses an encryption key to generate the key-dependent S-boxes and expanded key schedule for the Twofish algorithm. This is the only function which performs any dynamic allocation, and it must be called before encrypt or decrypt to produce a Session object. Keys may be 8, 16, 24, or 32 bits. Longer keys will be automatically truncate to 32 bits, and non-multiple-of-8 keys will be padded with 0 bytes.

encrypt and decrypt act on 16-byte blocks, reading from input starting at index io and writing to output starting at index oo. The input and output may be safely aliased. An in-place round trip for a single block may therefore be performed as follows:

const session = makeSession(key);
encrypt(block, 0, block, 0, session);
decrypt(block, 0, block, 0, session);

Note that this module only implements the basic block encryption algorithm. It is intended to provide the core block cipher to be plugged into a larger encryption algorithm, such as Cipher Block Chaining (CBC) or Counter mode (CTR) encryption.