85 lines
1.3 KiB
JavaScript
85 lines
1.3 KiB
JavaScript
/*
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* pkcs7.pad
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* https://github.com/brightcove/pkcs7
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*
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* Copyright (c) 2014 Brightcove
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* Licensed under the apache2 license.
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*/
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'use strict';
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var PADDING;
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/**
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* Returns a new Uint8Array that is padded with PKCS#7 padding.
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* @param plaintext {Uint8Array} the input bytes before encryption
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* @return {Uint8Array} the padded bytes
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* @see http://tools.ietf.org/html/rfc5652
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*/
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module.exports = function pad(plaintext) {
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var padding = PADDING[(plaintext.byteLength % 16) || 0],
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result = new Uint8Array(plaintext.byteLength + padding.length);
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result.set(plaintext);
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result.set(padding, plaintext.byteLength);
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return result;
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};
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// pre-define the padding values
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PADDING = [
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[16, 16, 16, 16,
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16, 16, 16, 16,
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16, 16, 16, 16,
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16, 16, 16, 16],
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[15, 15, 15, 15,
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15, 15, 15, 15,
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15, 15, 15, 15,
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15, 15, 15],
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[14, 14, 14, 14,
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14, 14, 14, 14,
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14, 14, 14, 14,
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14, 14],
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[13, 13, 13, 13,
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13, 13, 13, 13,
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13, 13, 13, 13,
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13],
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[12, 12, 12, 12,
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12, 12, 12, 12,
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12, 12, 12, 12],
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[11, 11, 11, 11,
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11, 11, 11, 11,
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11, 11, 11],
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[10, 10, 10, 10,
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10, 10, 10, 10,
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10, 10],
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[9, 9, 9, 9,
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9, 9, 9, 9,
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9],
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[8, 8, 8, 8,
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8, 8, 8, 8],
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[7, 7, 7, 7,
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7, 7, 7],
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[6, 6, 6, 6,
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6, 6],
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[5, 5, 5, 5,
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5],
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[4, 4, 4, 4],
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[3, 3, 3],
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[2, 2],
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[1]
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];
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