Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 | 1x 1x 1x 10x 10x | import randomBytes from 'randombytes';
import type { IModeOfOperation, IDecryptionModeOfOperation, IEncryptionModeOfOperation } from './IModeOfOperation';
import { xor } from '../../utils/xor';
export class OFBMode implements IModeOfOperation {
public readonly encryption = new OFBMode.OFBEncryptionMode();
public readonly decryption = new OFBMode.ECBDecryptionMode();
}
// istanbul ignore next
export namespace OFBMode {
export class OFBEncryptionMode implements IEncryptionModeOfOperation {
private initializationVector: Uint8Array | null = null;
public start(): Uint8Array {
this.initializationVector = randomBytes(16);
return this.initializationVector;
}
public combine(block: Uint8Array, encrypt: (block: Uint8Array) => Uint8Array): Uint8Array {
if (this.initializationVector === null)
throw new Error('OFB encryption mode not started.');
const encrypted = xor(this.initializationVector, encrypt(block));
this.initializationVector = encrypted;
return encrypted;
}
public finish(): Uint8Array {
this.initializationVector = null;
return new Uint8Array();
}
}
export class ECBDecryptionMode implements IDecryptionModeOfOperation {
private initializationVector: Uint8Array | null = null;
public start(): Uint8Array {
this.initializationVector = null;
return new Uint8Array();
}
public combine(block: Uint8Array, decrypt: (block: Uint8Array) => Uint8Array): Uint8Array {
if (this.initializationVector === null) {
this.initializationVector = block;
return new Uint8Array();
}
const decrypted = decrypt(xor(this.initializationVector, block));
this.initializationVector = block;
return decrypted;
}
public finish(): Uint8Array {
this.initializationVector = null;
return new Uint8Array();
}
}
}
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