Started to play around with js crypto code

test.js implements the basic functionality
(recommand to load it in v8 (d8 test.js --shell)

1 files changed, 71 insertions, 0 deletions

diff --git a/crypto/base64.js b/crypto/base64.js
new file mode 100644
index 0000000..f5b168c
--- /dev/null
+++ b/crypto/base64.js
@@ -0,0 +1,71 @@
+var b64map="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+var b64pad="=";
+
+function hex2b64(h) {
+  var i;
+  var c;
+  var ret = "";
+  for(i = 0; i+3 <= h.length; i+=3) {
+    c = parseInt(h.substring(i,i+3),16);
+    ret += b64map.charAt(c >> 6) + b64map.charAt(c & 63);
+  }
+  if(i+1 == h.length) {
+    c = parseInt(h.substring(i,i+1),16);
+    ret += b64map.charAt(c << 2);
+  }
+  else if(i+2 == h.length) {
+    c = parseInt(h.substring(i,i+2),16);
+    ret += b64map.charAt(c >> 2) + b64map.charAt((c & 3) << 4);
+  }
+  while((ret.length & 3) > 0) ret += b64pad;
+  return ret;
+}
+
+// convert a base64 string to hex
+function b64tohex(s) {
+  var ret = ""
+  var i;
+  var k = 0; // b64 state, 0-3
+  var slop;
+  for(i = 0; i < s.length; ++i) {
+    if(s.charAt(i) == b64pad) break;
+    v = b64map.indexOf(s.charAt(i));
+    if(v < 0) continue;
+    if(k == 0) {
+      ret += int2char(v >> 2);
+      slop = v & 3;
+      k = 1;
+    }
+    else if(k == 1) {
+      ret += int2char((slop << 2) | (v >> 4));
+      slop = v & 0xf;
+      k = 2;
+    }
+    else if(k == 2) {
+      ret += int2char(slop);
+      ret += int2char(v >> 2);
+      slop = v & 3;
+      k = 3;
+    }
+    else {
+      ret += int2char((slop << 2) | (v >> 4));
+      ret += int2char(v & 0xf);
+      k = 0;
+    }
+  }
+  if(k == 1)
+    ret += int2char(slop << 2);
+  return ret;
+}
+
+// convert a base64 string to a byte/number array
+function b64toBA(s) {
+  //piggyback on b64tohex for now, optimize later
+  var h = b64tohex(s);
+  var i;
+  var a = new Array();
+  for(i = 0; 2*i < h.length; ++i) {
+    a[i] = parseInt(h.substring(2*i,2*i+2),16);
+  }
+  return a;
+}