Differential D7061 Diff 23948 lib/utils/pkcs7-padding.js

Changeset View

Standalone View

lib/utils/pkcs7-padding.js

Show All 10 Lines
* to the standard PKCS#7 padding, but operates on the block basis instead of		* to the standard PKCS#7 padding, but operates on the block basis instead of
* the byte basis. The fill value of the padding is the number of blocks added.		* the byte basis. The fill value of the padding is the number of blocks added.
*		*
* The PKCS#7 padding is described in RFC 5652, section 6.3.		* The PKCS#7 padding is described in RFC 5652, section 6.3.
*/		*/

import invariant from 'invariant';		import invariant from 'invariant';

		export type PaddingConfiguration = {
		+blockSizeBytes: number,
		+superblockSizeBlocks: number,
		};

		/**
		* The padding configuration for 10KB superblocks.
		* The block size is 250 bytes, and the superblock size is 40 blocks.
		*/
		const PKCS7_10KB: PaddingConfiguration = {
		blockSizeBytes: 250,
		superblockSizeBlocks: 40,
		};

		/**
		* Pads the input using the extended PKCS#7 padding (superblock padding).
		* The input is first padded using the standard PKCS#7 padding, and then
		* padded to the nearest multiple of superblocks (blocks of blocks).
		*
		* @param {Uint8Array} data - The input to be padded.
		* @param {PaddingConfiguration} paddingConfiguration - The padding
		* configuration. Defaults to multiple of 10KB. See {@link PKCS7_10KB}.
		* @returns {Uint8Array} The padded input.
		*/
		function pad(
		data: Uint8Array,
		{ blockSizeBytes, superblockSizeBlocks }: PaddingConfiguration = PKCS7_10KB,
		): Uint8Array {
		const pkcs7Padded = pkcs7pad(data, blockSizeBytes);
		return superblockPad(pkcs7Padded, blockSizeBytes, superblockSizeBlocks);
		}

		/**
		* Unpads the input using the extended PKCS#7 padding (superblock padding).
		* The input is first unpadded on the block basis, and then unpadded using
		* the standard PKCS#7 padding.
		*
		* @param {Uint8Array} data - The input to be unpadded.
		* @param {PaddingConfiguration} paddingConfiguration - The padding
		* configuration. Defaults to multiple of 10KB. See {@link PKCS7_10KB}.
		* @returns {Uint8Array} The unpadded input.
		*/
		function unpad(
		data: Uint8Array,
		{ blockSizeBytes }: PaddingConfiguration = PKCS7_10KB,
		): Uint8Array {
		const blockUnpadded = superblockUnpad(data, blockSizeBytes);
		return pkcs7unpad(blockUnpadded);
		}

/**		/**
* PKCS#7 padding function for `Uint8Array` data.		* PKCS#7 padding function for `Uint8Array` data.
*		*
* @param {Uint8Array} data - The data to be padded.		* @param {Uint8Array} data - The data to be padded.
* @param {number} blockSizeBytes - The block size in bytes.		* @param {number} blockSizeBytes - The block size in bytes.
* @returns {Uint8Array} The padded data as a new Uint8Array.		* @returns {Uint8Array} The padded data as a new Uint8Array.
*/		*/
function pkcs7pad(data: Uint8Array, blockSizeBytes: number): Uint8Array {		function pkcs7pad(data: Uint8Array, blockSizeBytes: number): Uint8Array {
▲ Show 20 Lines • Show All 87 Lines • ▼ Show 20 Lines	invariant(
data.subarray(unpaddedLengthBytes).every(x => x === paddingBlocks),		data.subarray(unpaddedLengthBytes).every(x => x === paddingBlocks),
'invalid padding',		'invalid padding',
);		);

const unpaddedData = data.subarray(0, unpaddedLengthBytes);		const unpaddedData = data.subarray(0, unpaddedLengthBytes);
return unpaddedData;		return unpaddedData;
}		}

export { pkcs7pad, pkcs7unpad, superblockPad, superblockUnpad };		export { PKCS7_10KB, pad, unpad };

		// exported for testing purposes only
		export const testing = {
		pkcs7pad,
		pkcs7unpad,
		superblockPad,
		superblockUnpad,
		};