set6: task42 completed

2 files changed, 114 insertions, 0 deletions

diff --git a/lib/lib6.c b/lib/lib6.c
index e69de29..fe2cd60 100644
--- a/lib/lib6.c
+++ b/lib/lib6.c
@@ -0,0 +1,98 @@
+#include "lib6.h"
+#include "lib5.h"
+#include "lib4.h"
+#include "lib3.h"
+#include "lib2.h"
+#include "lib.h"
+
+
+int rsa_sign_bignum(BIGNUM *message, BIGNUM *signed_message, struct rsa_key_bignum *private)
+{
+	rsa_encrypt_bignum(message, signed_message, private);
+}
+
+int rsa_verify_bignum(BIGNUM *signed_message, BIGNUM *org_message, struct rsa_key_bignum *public)
+{
+	BIGNUM *res = BN_new();
+	int ret = -1;
+
+	rsa_decrypt_bignum(signed_message, res, public);
+	ret = BN_cmp(res, org_message);
+	printf("\nverfied mess ret: %i, message:\n", ret);
+	BN_print(out, res);
+	printf("\n");
+	BN_free(res);
+
+	return ret == 0;
+}
+/**
+  * construct a VALID pkcs_padding
+  **/
+void pkcs1_5_padding(char *message, char *result, unsigned int target_length_byte)
+{
+	SHA1Context sha1;
+	char sha1_hash[20];
+	int i;
+
+	memset(result, 0xff, target_length_byte);
+	result[0] = 0x00;
+	result[1] = 0x01;
+	result[target_length_byte-21] = 0x00;	
+
+	// TODO ASN.1 things
+
+	SHA1Reset(&sha1);
+	SHA1Input(&sha1, message, strlen(message));
+	SHA1Result(&sha1);
+	memcpy(sha1_hash, &(sha1.Message_Digest), 20);
+
+	for(i = 20;i>0;i--)
+		result[target_length_byte-i] = sha1_hash[20-i];
+}
+
+int pkcs1_5_padding_verify(char *to_verify, int len, char *message)
+{
+	char result[1024/8];
+	int i;
+
+	// construct the padding how the expect it and than compare
+	pkcs1_5_padding(message, result, 1024/8);
+	// printf both paddings
+	char buf[(1024/8)*2];
+	hex_binary_to_string(result, buf, 1024/8);
+	printf("expected padding:\n%s\n", buf);
+	hex_binary_to_string(to_verify, buf, len);
+	printf("got:\n%s\n", buf);
+
+	return memcmp(to_verify, result, 128) == 0;
+}
+
+int shitty_pkcs1_5_padding_verify(char *to_verify, int len, char *message)
+{
+	int i = 2;
+	SHA1Context sha1;
+	char sha1_hash[20];
+
+	if (len < 2 && to_verify[0] != 0x00 && to_verify[1] != 0x01)
+		return 0;
+
+	// search for the next 0x00 no matter what's in between
+	while(to_verify[i] != 0x00)
+		i++;
+
+	i++;
+	// TODO check asn.1 things
+	// verfiy the hash
+	SHA1Reset(&sha1);
+	SHA1Input(&sha1, message, strlen(message));
+	SHA1Result(&sha1);
+	memcpy(sha1_hash, &(sha1.Message_Digest), 20);
+	
+	int j;
+	for(j=0;j<20;j++, i++) {
+		if (to_verify[i] != sha1_hash[j])
+			return 0;
+	}
+
+	return 1;
+}
diff --git a/lib/lib6.h b/lib/lib6.h
index e69de29..23741b0 100644
--- a/lib/lib6.h
+++ b/lib/lib6.h
@@ -0,0 +1,16 @@
+#ifndef __LIB_6_H__
+#define __LIB_6_H__
+#include "lib6.h"
+#include "lib5.h"
+#include "lib4.h"
+#include "lib3.h"
+#include "lib2.h"
+#include "lib.h"
+
+
+int rsa_sign_bignum(BIGNUM *message, BIGNUM *signed_message, struct rsa_key_bignum *private);
+int rsa_verify_bignum(BIGNUM *signed_message, BIGNUM *org_message, struct rsa_key_bignum *public);
+int shitty_pkcs1_5_padding_verify(char *to_verify, int len, char *message);
+int pkcs1_5_padding_verify(char *to_verify, int len, char *message);
+
+#endif /* __LIB_6_H__ */