From: Rudolf Polzer <divverent@alientrap.org>
Date: Thu, 8 Jul 2010 18:07:32 +0000 (+0200)
Subject: a "fastreject" facility helpful to generate keys with a specific facility (only makes... 
X-Git-Tag: xonotic-v0.1.0preview~38^2~15^2~6
X-Git-Url: https://git.rm.cloudns.org/?a=commitdiff_plain;h=2060c9a103a104b87de2efa57384d89806b947ef;p=xonotic%2Fd0_blind_id.git

a "fastreject" facility helpful to generate keys with a specific facility (only makes sense for the RSA part)
---

diff --git a/Makefile.am b/Makefile.am
index da2a57b..7706cf3 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -6,7 +6,7 @@ blind_id_LDADD = libblind_id.la
 
 lib_LTLIBRARIES = libblind_id.la
 libblind_id_la_SOURCES = d0_bignum-gmp.c d0_blind_id.c d0.c d0_iobuf.c sha1.c
-libblind_id_la_LDFLAGS = -versioninfo 0:0:0
+libblind_id_la_LDFLAGS = -versioninfo 1:0:1
 libblind_id_la_CFLAGS = -fvisibility=hidden -Wold-style-definition -Wstrict-prototypes -Wsign-compare -Wdeclaration-after-statement
 # versioninfo:
 #   - compatible interface change: c:r:a -> c+1:0:a+1
diff --git a/d0_blind_id.c b/d0_blind_id.c
index 7c1f010..f366b52 100644
--- a/d0_blind_id.c
+++ b/d0_blind_id.c
@@ -189,7 +189,7 @@ BOOL d0_rsa_generate_key(size_t size, const d0_bignum_t *challenge, d0_bignum_t
 
 	// n = temp0*temp1
 	CHECK(d0_bignum_mul(n, temp0, temp1));
-		
+
 	// d = challenge^-1 mod (temp0-1)(temp1-1)
 	CHECK(d0_bignum_mul(temp0, temp2, temp3));
 	CHECK(d0_bignum_mod_inv(d, challenge, temp0));
@@ -198,6 +198,65 @@ fail:
 	return 0;
 }
 
+BOOL d0_rsa_generate_key_fastreject(size_t size, d0_fastreject_function reject, d0_blind_id_t *ctx, void *pass)
+{
+	// uses temp0 to temp4
+	int fail = 0;
+	int gcdfail = 0;
+	int pb = (size + 1)/2;
+	int qb = size - pb;
+	if(pb < 8)
+		pb = 8;
+	if(qb < 8)
+		qb = 8;
+        for (;;)
+	{
+		CHECK(d0_bignum_rand_bit_exact(temp0, pb));
+		if(d0_bignum_isprime(temp0, 10) == 0)
+			continue;
+		CHECK(d0_bignum_sub(temp2, temp0, one));
+		CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp2, ctx->rsa_e));
+		if(!d0_bignum_cmp(temp4, one))
+			break;
+		if(++gcdfail == 3)
+			return 0;
+		++gcdfail;
+	}
+	gcdfail = 0;
+        for (;;)
+	{
+		CHECK(d0_bignum_rand_bit_exact(temp1, qb));
+		if(!d0_bignum_cmp(temp1, temp0))
+		{
+			if(++fail == 3)
+				return 0;
+		}
+		fail = 0;
+
+		// n = temp0*temp1
+		CHECK(d0_bignum_mul(ctx->rsa_n, temp0, temp1));
+		if(reject(ctx, pass))
+			continue;
+
+		if(d0_bignum_isprime(temp1, 10) == 0)
+			continue;
+		CHECK(d0_bignum_sub(temp3, temp1, one));
+		CHECK(d0_bignum_gcd(temp4, NULL, NULL, temp3, ctx->rsa_e));
+		if(!d0_bignum_cmp(temp4, one))
+			break;
+		if(++gcdfail == 3)
+			return 0;
+		++gcdfail;
+	}
+
+	// ctx->rsa_d = ctx->rsa_e^-1 mod (temp0-1)(temp1-1)
+	CHECK(d0_bignum_mul(temp0, temp2, temp3));
+	CHECK(d0_bignum_mod_inv(ctx->rsa_d, ctx->rsa_e, temp0));
+	return 1;
+fail:
+	return 0;
+}
+
 void d0_blind_id_clear(d0_blind_id_t *ctx)
 {
 	if(ctx->rsa_n) d0_bignum_free(ctx->rsa_n);
@@ -233,19 +292,27 @@ void d0_blind_id_copy(d0_blind_id_t *ctx, const d0_blind_id_t *src)
 	memcpy(ctx->msghash, src->msghash, sizeof(ctx->msghash));
 }
 
-WARN_UNUSED_RESULT BOOL d0_blind_id_generate_private_key(d0_blind_id_t *ctx, int k)
+WARN_UNUSED_RESULT BOOL d0_blind_id_generate_private_key_fastreject(d0_blind_id_t *ctx, int k, d0_fastreject_function reject, void *pass)
 {
 	REPLACING(rsa_e); REPLACING(rsa_d); REPLACING(rsa_n);
 
 	CHECK_ASSIGN(ctx->rsa_e, d0_bignum_int(ctx->rsa_e, 65537));
 	CHECK_ASSIGN(ctx->rsa_d, d0_bignum_zero(ctx->rsa_d));
 	CHECK_ASSIGN(ctx->rsa_n, d0_bignum_zero(ctx->rsa_n));
-	CHECK(d0_rsa_generate_key(k+1, ctx->rsa_e, ctx->rsa_d, ctx->rsa_n)); // must fit G for sure
+	if(reject)
+		CHECK(d0_rsa_generate_key_fastreject(k+1, reject, ctx, pass)); // must fit G for sure
+	else
+		CHECK(d0_rsa_generate_key(k+1, ctx->rsa_e, ctx->rsa_d, ctx->rsa_n)); // must fit G for sure
 	return 1;
 fail:
 	return 0;
 }
 
+WARN_UNUSED_RESULT BOOL d0_blind_id_generate_private_key(d0_blind_id_t *ctx, int k)
+{
+	return d0_blind_id_generate_private_key_fastreject(ctx, k, NULL, NULL);
+}
+
 WARN_UNUSED_RESULT BOOL d0_blind_id_read_private_key(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen)
 {
 	d0_iobuf_t *in = NULL;
diff --git a/d0_blind_id.h b/d0_blind_id.h
index 511ea82..339f463 100644
--- a/d0_blind_id.h
+++ b/d0_blind_id.h
@@ -4,12 +4,14 @@
 #include "d0.h"
 
 typedef struct d0_blind_id_s d0_blind_id_t;
+typedef BOOL (*d0_fastreject_function) (d0_blind_id_t *ctx, void *pass);
 
 EXPORT WARN_UNUSED_RESULT d0_blind_id_t *d0_blind_id_new(void);
 EXPORT void d0_blind_id_free(d0_blind_id_t *a);
 EXPORT void d0_blind_id_clear(d0_blind_id_t *ctx);
 EXPORT void d0_blind_id_copy(d0_blind_id_t *ctx, const d0_blind_id_t *src);
 EXPORT WARN_UNUSED_RESULT BOOL d0_blind_id_generate_private_key(d0_blind_id_t *ctx, int k);
+EXPORT WARN_UNUSED_RESULT BOOL d0_blind_id_generate_private_key_fastreject(d0_blind_id_t *ctx, int k, d0_fastreject_function reject, void *pass);
 EXPORT WARN_UNUSED_RESULT BOOL d0_blind_id_read_private_key(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen);
 EXPORT WARN_UNUSED_RESULT BOOL d0_blind_id_read_public_key(d0_blind_id_t *ctx, const char *inbuf, size_t inbuflen);
 EXPORT WARN_UNUSED_RESULT BOOL d0_blind_id_write_private_key(d0_blind_id_t *ctx, char *outbuf, size_t *outbuflen);