import from sources:
uchar*		RSApubtoasn1(RSApub*, int*);
RSApub*		asn1toRSApub(uchar*, int);

Reference: /n/atom/patch/applied/asn1torsapriv
Date: Sat Mar 15 18:18:56 CET 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/include/libsec.h	Sat Mar 15 18:18:39 2014
+++ /sys/include/libsec.h	Sat Mar 15 18:18:40 2014
@@ -275,6 +275,8 @@
 void		rsaprivfree(RSApriv*);
 RSApub*		rsaprivtopub(RSApriv*);
 RSApub*		X509toRSApub(uchar*, int, char*, int);
+uchar*		RSApubtoasn1(RSApub*, int*);
+RSApub*		asn1toRSApub(uchar*, int);
 RSApriv*	asn1toRSApriv(uchar*, int);
 void		asn1dump(uchar *der, int len);
 uchar*		decodePEM(char *s, char *type, int *len, char **new_s);
--- /sys/man/2/rsa	Sat Mar 15 18:18:41 2014
+++ /sys/man/2/rsa	Sat Mar 15 18:18:42 2014
@@ -3,6 +3,7 @@
 asn1dump,
 asn1toDSApriv,
 asn1toRSApriv,
+asn1toRSApub,
 decodePEM,
 decodepemchain,
 rsadecrypt,
@@ -14,6 +15,7 @@
 rsaprivtopub,
 rsapuballoc,
 rsapubfree,
+RSApubtoasn1,
 X509dump,
 X509gen,
 X509req,
@@ -60,6 +62,9 @@
 RSApub*	X509toRSApub(uchar *cert, int ncert, char *name, int nname)
 .PP
 .B
+uchar* RSApubtoasn1(RSApub *pub, int *keylen)
+.PP
+.B
 RSApriv*	asn1toDSApriv(uchar *priv, int npriv)
 .PP
 .B
@@ -194,9 +199,20 @@
 .I X509dump
 prints a human-readble version of the certificate.
 .PP
-.I Asn1toDSApriv
+.I Asn1toRSApub
+converts an ASN1-formatted RSA public key into the corresponding
+.B RSApub
+structure.
+.PP
+.I RSApubtoasn1
+encodes an RSA public key using ASN.1 DER.  It returns a pointer
+to the encoded key; if keylen is non-nil, it sets
+.B *keylen
+to the length of the encoded key.
+.PP
+.I Asn1toRSApriv
 and
-.I asn1toRSApriv
+.I asn1toDSApriv
 converts an ASN1 formatted RSA private key into the corresponding
 .B DSApriv
 or
--- /sys/src/libsec/port/x509.c	Sat Mar 15 18:18:45 2014
+++ /sys/src/libsec/port/x509.c	Sat Mar 15 18:18:47 2014
@@ -2191,6 +2191,97 @@
 	return pk;
 }
 
+int
+getalgo(Elem *e)
+{
+	Value *v;
+	Elist *el;
+	int a;
+
+	if((a = parse_alg(e)) >= 0)
+		return a;
+	v = &e->val;
+	if(v->tag == VSeq){
+		print("Seq\n");
+		for(el = v->u.seqval; el!=nil; el = el->tl){
+			if((a = getalgo(&el->hd)) >= 0)
+				return a;
+		}
+	}
+	return -1;
+}
+
+static void edump(Elem e);
+
+RSApub*
+asn1toRSApub(uchar *der, int nder)
+{
+	Elem e;
+	Elist *el, *l;
+	int n;
+	Bits *b;
+	RSApub *key;
+	mpint *mp;
+
+	if(decode(der, nder, &e) != ASN_OK){
+		print("didn't parse\n");
+		return nil;
+	}
+	if(!is_seq(&e, &el)){
+		print("no seq");
+		return nil;
+	}
+	if((n = elistlen(el)) != 2){
+		print("bad length %d\n", n);
+		return nil;
+	}
+	if((n = getalgo(&el->hd)) < 0){
+		print("no algo\n");
+		return nil;
+	}
+	if(n != 0){
+		print("cant do algorithm %d\n", n);
+		return nil;
+	}
+	if(!is_bitstring(&el->tl->hd, &b)){
+		print("no bits\n");
+		return nil;
+	}
+	if(decode(b->data, b->len, &e) != ASN_OK){
+		print("no second decode\n");
+		return nil;
+	}
+	if(!is_seq(&e, &el)){
+		print("no second seq\n");
+		return nil;
+	}
+	if(elistlen(el) != 2){
+		print("no second length\n");
+		return nil;
+	}
+	key = rsapuballoc();
+
+	l = el;
+
+	key->n = mp = asn1mpint(&el->hd);
+	if(mp == nil)
+		goto errret;
+
+	el = el->tl;
+	key->ek = mp = asn1mpint(&el->hd);
+	if(mp == nil)
+		goto errret;
+
+	if(l != nil)
+		freeelist(l);
+	return key;
+errret:
+	if(l != nil)
+		freeelist(l);
+	rsapubfree(key);
+	return nil;
+}
+
 char*
 X509verify(uchar *cert, int ncert, RSApub *pk)
 {
@@ -2388,6 +2479,34 @@
 	return mkseq(el);
 }
 
+uchar*
+RSApubtoasn1(RSApub *pub, int *keylen)
+{
+	Elem pubkey;
+	Bytes *pkbytes;
+	uchar *key;
+
+	key = nil;
+	pubkey = mkseq(mkel(mkbigint(pub->n),mkel(mkint(mptoi(pub->ek)),nil)));
+	if(encode(pubkey, &pkbytes) != ASN_OK)
+		goto errret;
+	freevalfields(&pubkey.val);
+	pubkey = mkseq(
+		mkel(mkalg(ALG_rsaEncryption),
+		mkel(mkbits(pkbytes->data, pkbytes->len),
+		nil)));
+	freebytes(pkbytes);
+	if(encode(pubkey, &pkbytes) != ASN_OK)
+		goto errret;
+	if(keylen)
+		*keylen = pkbytes->len;
+	key = malloc(pkbytes->len);
+	memmove(key, pkbytes->data, pkbytes->len);
+	free(pkbytes);
+errret:
+	freevalfields(&pubkey.val);
+	return key;
+}
 
 uchar*
 X509gen(RSApriv *priv, char *subj, ulong valid[2], int *certlen)
@@ -2569,7 +2688,10 @@
 	case VBigInt: print("BigInt[%d] %.2x%.2x...",v.u.bigintval->len,v.u.bigintval->data[0],v.u.bigintval->data[1]); break;
 	case VReal: print("Real..."); break;
 	case VOther: print("Other..."); break;
-	case VBitString: print("BitString..."); break;
+	case VBitString: print("BitString");
+		for(i = 0; i<v.u.bitstringval->len; i++)
+			print(" %02x", v.u.bitstringval->data[i]);
+		break;
 	case VNull: print("Null"); break;
 	case VEOC: print("EOC..."); break;
 	case VObjId: print("ObjId");