1 files changed, 50 insertions, 0 deletions
diff --git a/libc/misc/crypt.c b/libc/misc/crypt.c
new file mode 100644
index 0000000..906dea2
--- /dev/null
+++ b/libc/misc/crypt.c
@@ -0,0 +1,50 @@
+#include <features.h>
+#include <stdlib.h>
+/* TEA based crypt(), version 0.0 <ndf@linux.mit.edu>
+ * It looks like there are problems with key bits carrying through
+ * to the encryted data, and I want to get rid of that libc call..
+ * This is just so rob could see it ;) */
+char *
+crypt(const char * key, const char * salt)
+{
+  /* n is the number of rounds, delta is a golden # derivative,
+   k is the key, v is the data to be encrypted. */
+  unsigned long v[2], sum=0, delta=0x9e3779b9, n=64, k[4];
+  static char rkey[16];
+  unsigned char i;
+
+  /* Our constant string will be a string of zeros .. */
+  v[0]=v[1]=k[0]=k[1]=k[2]=k[3]=0;
+  for(i=0;i<16;i++) rkey[i]=0;
+  rkey[0]=*salt;
+  rkey[1]=salt[1];
+  for (i=0;key[i];i++) rkey[i+1]=key[i];
+  memcpy(k, rkey, 4*sizeof(long));
+
+  while (n-->0)  {
+    sum += delta;
+    v[0] += (v[1]<<4)+k[0] ^ v[1]+sum ^ (v[1]>>5)+k[1];
+    v[1] += (v[0]<<4)+k[2] ^ v[0]+sum ^ (v[0]>>5)+k[3];
+  }
+
+  *rkey=*salt; rkey[1]=salt[1];
+
+  /* Now we need to unpack the bits and map it to "A-Za-z0-9./" for printing
+     in /etc/passwd */
+  for (i=2;i<13;i++)
+    {
+      /* This unpacks the 6 bit data, each cluster into its own byte */
+      if (i==8) v[0]|=v[1]>>28;
+      rkey[i]=v[(i-2)/6]&0x3F;
+      v[(i-2)/6]>>=6;
+
+      /* Now we map to the proper chars */
+      if (rkey[i]>=0 && rkey[i]<12) rkey[i]+=46;
+      else if (rkey[i]>11 && rkey[i]<38) rkey[i]+=53;
+      else if (rkey[i]>37 && rkey[i]<64) rkey[i]+=59;
+      else return NULL;
+    }
+
+  rkey[13]='\0';
+  return rkey;
+}