ref: ac9970d30b5153298b96d551379f99923b4d1a57
parent: 4ab0e6e7237a631dc096603c18a154b6d7669947
author: Ori Bernstein <ori@eigenstate.org>
date: Sat Jul 3 20:44:04 EDT 2021
add rsa2jwk.
--- /dev/null
+++ b/rsa2jwk.c
@@ -1,0 +1,87 @@
+#include <u.h>
+#include <libc.h>
+#include <auth.h>
+#include <mp.h>
+#include <libsec.h>
+#include "rsa2any.h"
+
+#define between(x,min,max) (((min-1-x) & (x-max-1))>>8)
+
+int
+encurl64chr(int o)
+{+ int c;
+
+ c = between(o, 0, 25) & ('A'+o);+ c |= between(o, 26, 51) & ('a'+(o-26));+ c |= between(o, 52, 61) & ('0'+(o-52));+ c |= between(o, 62, 62) & ('-');+ c |= between(o, 63, 63) & ('_');+ return c;
+}
+
+char*
+encurl64(void *in, int n)
+{+ int lim;
+ char *out, *p;
+
+ lim = 4*n/3 + 5;
+ if((out = malloc(lim)) == nil)
+ sysfatal("malloc: %r");+ enc64x(out, lim, in, n, encurl64chr);
+ if((p = strchr(out, '=')) != nil)
+ *p = 0;
+ return out;
+}
+
+void
+usage(void)
+{+ fprint(2, "usage: auth/rsa2pub [file]\n");
+ exits("usage");+}
+
+void
+main(int argc, char **argv)
+{+ uchar nbuf[8192], ebuf[512];
+ char *nstr, *estr;
+ RSApriv *k;
+ int nlen, elen;
+
+ fmtinstall('[', encodefmt);+ quotefmtinstall();
+
+ ARGBEGIN{+ default:
+ usage();
+ }ARGEND
+
+ if(argc > 1)
+ usage();
+
+ if((k = getrsakey(argc, argv, 0, nil)) == nil)
+ sysfatal("%r");+
+ nlen = (mpsignif(k->pub.n)+7)/8;
+ if(nlen >= sizeof(nbuf))
+ sysfatal("key too big");+ mptobe(k->pub.n, nbuf, nlen, nil);
+ nstr = encurl64(nbuf, nlen);
+
+ elen = (mpsignif(k->pub.ek)+7)/8;
+ if(elen >= sizeof(ebuf))
+ sysfatal("key too big");+ mptobe(k->pub.ek, ebuf, elen, nil);
+ estr = encurl64(ebuf, elen);
+
+ print(
+ "{"+ "\"kty\": \"RSA\","
+ "\"n\": \"%s\","
+ "\"e\": \"%s\""
+ "}\n",
+ nstr, estr);
+ exits(nil);
+}