Added test tool for checking the ECC maximum signature length. Iterates through each supported curve and loops the sign/verify to determine at run-time the maximum ECC signature size for each curve.

signature/sigtest/Makefile

@@ -8,7 +8,7 @@ WOLFSSL_FLAGS=
 OPENSSL_LIB=-L$(OPENSSL_DIR)/openssl/lib -lcrypto -lssl
 WOLFSSL_LIB=-lwolfssl
 
-all:wolfsigtest opensigtest
+all:wolfsigtest opensigtest eccsiglentest
 
 opensigtest:CFLAGS+=$(OPENSSL_FLAGS)
 opensigtest:opensigtest.o
@@ -18,7 +18,11 @@ wolfsigtest:CFLAGS+=$(WOLFSSL_FLAGS)
 wolfsigtest:wolfsigtest.o
 	$(CC) -o $@ $(LIBS) $(WOLFSSL_LIB) $^ $(CFLAGS)
 
+eccsiglentest:CFLAGS+=$(WOLFSSL_FLAGS)
+eccsiglentest:eccsiglentest.o
+	$(CC) -o $@ $(LIBS) $(WOLFSSL_LIB) $^ $(CFLAGS)
+
 .PHONY: clean all
 
 clean:
-	rm -f *.o wolfsigtest opensigtest
+	rm -f *.o wolfsigtest opensigtest eccsiglentest

signature/sigtest/README.md

@@ -7,7 +7,7 @@ Demonstrates using a hash digest to sign and verify a signature using RSA
 ### Build and install wolfSSL
 
 ```
-./configure && make && sudo make install
+./configure --enable-certgen --enable-certext && make && sudo make install
 ```
 
 ### Build example
@@ -32,3 +32,41 @@ CRYPTO: signature verify OK! 1
 CRYPTO: EXPECTED signature verify OK! 1
 
 ```
+
+### ECC Signature Length Test 
+
+Built wolfSSL with: `./configure --enable-ecccustcurves=all && make && sudo make install`
+
+```
+./eccsiglentest README.md 
+Signature Length Test: Loops 1000
+File README.md is 452 bytes
+ECC Curve SECP192R1, KeySz 24, Sig: ActMax 56, CalcMax 58
+ECC Curve PRIME192V2, KeySz 24, Sig: ActMax 56, CalcMax 58
+ECC Curve PRIME192V3, KeySz 24, Sig: ActMax 56, CalcMax 58
+ECC Curve PRIME239V1, KeySz 30, Sig: ActMax 66, CalcMax 70
+ECC Curve PRIME239V2, KeySz 30, Sig: ActMax 66, CalcMax 70
+ECC Curve PRIME239V3, KeySz 30, Sig: ActMax 66, CalcMax 70
+ECC Curve SECP256R1, KeySz 32, Sig: ActMax 72, CalcMax 74
+ECC Curve SECP112R1, KeySz 14, Sig: ActMax 36, CalcMax 38
+ECC Curve SECP112R2, KeySz 14, Sig: ActMax 34, CalcMax 38
+ECC Curve SECP128R1, KeySz 16, Sig: ActMax 40, CalcMax 42
+ECC Curve SECP128R2, KeySz 16, Sig: ActMax 38, CalcMax 42
+ECC Curve SECP160R1, KeySz 20, Sig: ActMax 48, CalcMax 50
+ECC Curve SECP160R2, KeySz 20, Sig: ActMax 48, CalcMax 50
+ECC Curve SECP224R1, KeySz 28, Sig: ActMax 64, CalcMax 66
+ECC Curve SECP384R1, KeySz 48, Sig: ActMax 104, CalcMax 106
+ECC Curve SECP521R1, KeySz 66, Sig: ActMax 139, CalcMax 142
+ECC Curve SECP160K1, KeySz 20, Sig: ActMax 48, CalcMax 50
+ECC Curve SECP192K1, KeySz 24, Sig: ActMax 56, CalcMax 58
+ECC Curve SECP224K1, KeySz 28, Sig: ActMax 64, CalcMax 66
+ECC Curve SECP256K1, KeySz 32, Sig: ActMax 72, CalcMax 74
+ECC Curve BRAINPOOLP160R1, KeySz 20, Sig: ActMax 48, CalcMax 50
+ECC Curve BRAINPOOLP192R1, KeySz 24, Sig: ActMax 56, CalcMax 58
+ECC Curve BRAINPOOLP224R1, KeySz 28, Sig: ActMax 64, CalcMax 66
+ECC Curve BRAINPOOLP256R1, KeySz 32, Sig: ActMax 72, CalcMax 74
+ECC Curve BRAINPOOLP320R1, KeySz 40, Sig: ActMax 88, CalcMax 90
+ECC Curve BRAINPOOLP384R1, KeySz 48, Sig: ActMax 104, CalcMax 106
+```
+
+Note: The extra 2-bytes of padding is to account for the case where the base ECC key has the Most Significant Bit (MSB) set, which would cause a longer signature.

signature/sigtest/wolfsigtest.c

@@ -13,9 +13,7 @@
 #include "wolfssl/wolfcrypt/rsa.h"      // For RSA functions
 
 /* wolfSSL must be build with WOLFSSL_CERT_EXT defined */
-#ifndef WOLFSSL_CERT_EXT
+#ifdef WOLFSSL_CERT_EXT
-    #error wolfSSL must be build with WOLFSSL_CERT_EXT enable ./configure --enable-certgen --enable-certext
-#endif
 
 /* this is from ./certs/ca-key.pem */
 const char* pubPemKey  = "-----BEGIN PUBLIC KEY-----\n"
@@ -217,3 +215,15 @@ exit:
    wc_FreeRng(&rng);
    return 0;
 }
+
+#else
+
+int main(int argc, char** argv)
+{
+    (void)argc;
+    (void)argv;
+    printf("Error wolfSSL must be build with WOLFSSL_CERT_EXT enable ./configure --enable-certgen --enable-certext\n");
+    return 0;
+}
+
+#endif /* WOLFSSL_CERT_EXT */