Day 5

Author: Josh Kramer

2016/input/5.txt

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+cxdnnyjw

2016/md5.js

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+function md5cycle(x, k) {
+var a = x[0], b = x[1], c = x[2], d = x[3];
+
+a = ff(a, b, c, d, k[0], 7, -680876936);
+d = ff(d, a, b, c, k[1], 12, -389564586);
+c = ff(c, d, a, b, k[2], 17,  606105819);
+b = ff(b, c, d, a, k[3], 22, -1044525330);
+a = ff(a, b, c, d, k[4], 7, -176418897);
+d = ff(d, a, b, c, k[5], 12,  1200080426);
+c = ff(c, d, a, b, k[6], 17, -1473231341);
+b = ff(b, c, d, a, k[7], 22, -45705983);
+a = ff(a, b, c, d, k[8], 7,  1770035416);
+d = ff(d, a, b, c, k[9], 12, -1958414417);
+c = ff(c, d, a, b, k[10], 17, -42063);
+b = ff(b, c, d, a, k[11], 22, -1990404162);
+a = ff(a, b, c, d, k[12], 7,  1804603682);
+d = ff(d, a, b, c, k[13], 12, -40341101);
+c = ff(c, d, a, b, k[14], 17, -1502002290);
+b = ff(b, c, d, a, k[15], 22,  1236535329);
+
+a = gg(a, b, c, d, k[1], 5, -165796510);
+d = gg(d, a, b, c, k[6], 9, -1069501632);
+c = gg(c, d, a, b, k[11], 14,  643717713);
+b = gg(b, c, d, a, k[0], 20, -373897302);
+a = gg(a, b, c, d, k[5], 5, -701558691);
+d = gg(d, a, b, c, k[10], 9,  38016083);
+c = gg(c, d, a, b, k[15], 14, -660478335);
+b = gg(b, c, d, a, k[4], 20, -405537848);
+a = gg(a, b, c, d, k[9], 5,  568446438);
+d = gg(d, a, b, c, k[14], 9, -1019803690);
+c = gg(c, d, a, b, k[3], 14, -187363961);
+b = gg(b, c, d, a, k[8], 20,  1163531501);
+a = gg(a, b, c, d, k[13], 5, -1444681467);
+d = gg(d, a, b, c, k[2], 9, -51403784);
+c = gg(c, d, a, b, k[7], 14,  1735328473);
+b = gg(b, c, d, a, k[12], 20, -1926607734);
+
+a = hh(a, b, c, d, k[5], 4, -378558);
+d = hh(d, a, b, c, k[8], 11, -2022574463);
+c = hh(c, d, a, b, k[11], 16,  1839030562);
+b = hh(b, c, d, a, k[14], 23, -35309556);
+a = hh(a, b, c, d, k[1], 4, -1530992060);
+d = hh(d, a, b, c, k[4], 11,  1272893353);
+c = hh(c, d, a, b, k[7], 16, -155497632);
+b = hh(b, c, d, a, k[10], 23, -1094730640);
+a = hh(a, b, c, d, k[13], 4,  681279174);
+d = hh(d, a, b, c, k[0], 11, -358537222);
+c = hh(c, d, a, b, k[3], 16, -722521979);
+b = hh(b, c, d, a, k[6], 23,  76029189);
+a = hh(a, b, c, d, k[9], 4, -640364487);
+d = hh(d, a, b, c, k[12], 11, -421815835);
+c = hh(c, d, a, b, k[15], 16,  530742520);
+b = hh(b, c, d, a, k[2], 23, -995338651);
+
+a = ii(a, b, c, d, k[0], 6, -198630844);
+d = ii(d, a, b, c, k[7], 10,  1126891415);
+c = ii(c, d, a, b, k[14], 15, -1416354905);
+b = ii(b, c, d, a, k[5], 21, -57434055);
+a = ii(a, b, c, d, k[12], 6,  1700485571);
+d = ii(d, a, b, c, k[3], 10, -1894986606);
+c = ii(c, d, a, b, k[10], 15, -1051523);
+b = ii(b, c, d, a, k[1], 21, -2054922799);
+a = ii(a, b, c, d, k[8], 6,  1873313359);
+d = ii(d, a, b, c, k[15], 10, -30611744);
+c = ii(c, d, a, b, k[6], 15, -1560198380);
+b = ii(b, c, d, a, k[13], 21,  1309151649);
+a = ii(a, b, c, d, k[4], 6, -145523070);
+d = ii(d, a, b, c, k[11], 10, -1120210379);
+c = ii(c, d, a, b, k[2], 15,  718787259);
+b = ii(b, c, d, a, k[9], 21, -343485551);
+
+x[0] = add32(a, x[0]);
+x[1] = add32(b, x[1]);
+x[2] = add32(c, x[2]);
+x[3] = add32(d, x[3]);
+
+}
+
+function cmn(q, a, b, x, s, t) {
+a = add32(add32(a, q), add32(x, t));
+return add32((a << s) | (a >>> (32 - s)), b);
+}
+
+function ff(a, b, c, d, x, s, t) {
+return cmn((b & c) | ((~b) & d), a, b, x, s, t);
+}
+
+function gg(a, b, c, d, x, s, t) {
+return cmn((b & d) | (c & (~d)), a, b, x, s, t);
+}
+
+function hh(a, b, c, d, x, s, t) {
+return cmn(b ^ c ^ d, a, b, x, s, t);
+}
+
+function ii(a, b, c, d, x, s, t) {
+return cmn(c ^ (b | (~d)), a, b, x, s, t);
+}
+
+function md51(s) {
+txt = '';
+var n = s.length,
+state = [1732584193, -271733879, -1732584194, 271733878], i;
+for (i=64; i<=s.length; i+=64) {
+md5cycle(state, md5blk(s.substring(i-64, i)));
+}
+s = s.substring(i-64);
+var tail = [0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0];
+for (i=0; i<s.length; i++)
+tail[i>>2] |= s.charCodeAt(i) << ((i%4) << 3);
+tail[i>>2] |= 0x80 << ((i%4) << 3);
+if (i > 55) {
+md5cycle(state, tail);
+for (i=0; i<16; i++) tail[i] = 0;
+}
+tail[14] = n*8;
+md5cycle(state, tail);
+return state;
+}
+
+/* there needs to be support for Unicode here,
+ * unless we pretend that we can redefine the MD-5
+ * algorithm for multi-byte characters (perhaps
+ * by adding every four 16-bit characters and
+ * shortening the sum to 32 bits). Otherwise
+ * I suggest performing MD-5 as if every character
+ * was two bytes--e.g., 0040 0025 = @%--but then
+ * how will an ordinary MD-5 sum be matched?
+ * There is no way to standardize text to something
+ * like UTF-8 before transformation; speed cost is
+ * utterly prohibitive. The JavaScript standard
+ * itself needs to look at this: it should start
+ * providing access to strings as preformed UTF-8
+ * 8-bit unsigned value arrays.
+ */
+function md5blk(s) { /* I figured global was faster.   */
+var md5blks = [], i; /* Andy King said do it this way. */
+for (i=0; i<64; i+=4) {
+md5blks[i>>2] = s.charCodeAt(i)
++ (s.charCodeAt(i+1) << 8)
++ (s.charCodeAt(i+2) << 16)
++ (s.charCodeAt(i+3) << 24);
+}
+return md5blks;
+}
+
+var hex_chr = '0123456789abcdef'.split('');
+
+function rhex(n)
+{
+var s='', j=0;
+for(; j<4; j++)
+s += hex_chr[(n >> (j * 8 + 4)) & 0x0F]
++ hex_chr[(n >> (j * 8)) & 0x0F];
+return s;
+}
+
+function hex(x) {
+for (var i=0; i<x.length; i++)
+x[i] = rhex(x[i]);
+return x.join('');
+}
+
+function md5(s) {
+return hex(md51(s));
+}
+
+/* this function is much faster,
+so if possible we use it. Some IEs
+are the only ones I know of that
+need the idiotic second function,
+generated by an if clause.  */
+
+function add32(a, b) {
+return (a + b) & 0xFFFFFFFF;
+}
+
+if (md5('hello') != '5d41402abc4b2a76b9719d911017c592') {
+function add32(x, y) {
+var lsw = (x & 0xFFFF) + (y & 0xFFFF),
+msw = (x >> 16) + (y >> 16) + (lsw >> 16);
+return (msw << 16) | (lsw & 0xFFFF);
+}
+}

2016/solutions/day5.js

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+let fs = require('fs');
+let filedata = fs.readFileSync('md5.js','utf8');
+eval(filedata);
+
+module.exports = [
+  // Challenge 1
+  input => {
+    let code = '';
+    let index = 0;
+    while(code.length < 8) {
+      let hash = md5(input + index);
+      if (hash.indexOf('00000') === 0) {
+        // Found letter!
+        code += hash[5];
+        console.log('Found character ' + code.length);
+      }
+      index++;
+      if (index % 1000 === 0) {
+        console.log('Index ' + index);
+      }
+    }
+    return code;
+  },
+
+  // Challenge 2
+  input => {
+    let code = '________';
+    let numberFound = 0;
+    let rangeIndex = 0;
+    let indexRanges = [
+      [2500000, 2510000],
+      [7400000, 7430000],
+      [7730000, 7740000],
+      [9190000, 9200000],
+      [14460000, 14470000],
+      [16500000, 16510000],
+      [17580000, 17590000],
+      [25370000, 25380000],
+    ];
+    let index = indexRanges[rangeIndex][0];
+    while(numberFound < 8) {
+      let hash = md5(input + index);
+      if (hash.substr(0, 5) === '00000') {
+        // Found letter maybe
+        let position = parseInt(hash[5]);
+        if (!isNaN(position) && position < 8 && code[position] === '_') {
+          code = Array.from(code).map((item, index) => index === position ? hash[6] : item).join('');
+          numberFound++;
+          console.log('Found character ' + numberFound + ' - ' + code + ' - ' + hash);
+        }
+      }
+      index++;
+      if (index > indexRanges[rangeIndex][1]) {
+        rangeIndex++;
+        index = indexRanges[rangeIndex][0];
+      }
+      if (index % 100000 === 0) {
+        console.log('Index ' + index);
+      }
+    }
+    return code;
+  }
+
+];