* Pre-processes message to feed the algorithm loop * * @param {string} message - message to pre-process * @return {string} - processed message
(message)
| 65 | * @return {string} - processed message |
| 66 | */ |
| 67 | function preProcess(message) { |
| 68 | // convert message to binary representation padded to |
| 69 | // 8 bits, and add 1 |
| 70 | let m = |
| 71 | message |
| 72 | .split('') |
| 73 | .map((e) => e.charCodeAt(0)) |
| 74 | .map((e) => e.toString(2)) |
| 75 | .map((e) => pad(e, 8)) |
| 76 | .join('') + '1' |
| 77 | |
| 78 | // extend message by adding empty bits (0) |
| 79 | while (m.length % 512 !== 448) { |
| 80 | m += '0' |
| 81 | } |
| 82 | |
| 83 | // length of message in binary, padded, and extended |
| 84 | // to a 64 bit representation |
| 85 | let ml = (message.length * CHAR_SIZE).toString(2) |
| 86 | ml = pad(ml, 8) |
| 87 | ml = '0'.repeat(64 - ml.length) + ml |
| 88 | |
| 89 | return m + ml |
| 90 | } |
| 91 | |
| 92 | /** |
| 93 | * Hashes message using SHA-1 Cryptographic Hash Function |