GEEKING

Base/rbx/Unix/Crypt.cpp

@@ -0,0 +1,135 @@
+#include "rbx/Crypt.h"
+#include "rbxFormat.h"
+#include <boost/scoped_array.hpp>
+
+#include <iostream>
+#include <string>
+#include <sstream>
+
+#if defined(__APPLE__)
+#   include <TargetConditionals.h>
+#   if defined(__i386__) && !TARGET_IPHONE_SIMULATOR
+#       define RBX_BUILD_CRYPT
+#   endif
+#elif defined(__ANDROID__)
+#   define RBX_BUILD_CRYPT
+#else
+#   error Unsupported platform.
+#endif
+
+#ifdef RBX_BUILD_CRYPT
+#   include <openssl/sha.h>
+#   include <openssl/bio.h>
+#   include <openssl/x509.h>
+#   include <openssl/evp.h>
+#   include <openssl/pem.h>
+#   include <openssl/err.h>
+#endif // RBX_BUILD_CRYPT
+
+namespace
+{
+#ifdef RBX_BUILD_CRYPT
+// The stuff between "-----BEGIN PUBLIC KEY-----" is base64 encoded string, the roblox key is also base64 encoded & should work.
+
+// Public/Private Key Pair generated by Ben D from the public/private blobs
+char publicKey[] = {
+    "-----BEGIN PUBLIC KEY-----\n"
+    "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC6F81Z5VyQgc9bs0Ez0W+UCrmt\n"
+    "VuOmonInljZETWRuMbZwvvOJrXdjb3K1hG8ycnoQGfEmGLpDDjYgOmxa3Jzt+2Yo\n"
+    "d2WGnHahH8Tk+fVVC/8nVTwKHRBYhQcG7Vm+99nRhKCv7Dd6quOLdfjhrBGexxee\n"
+    "dqyepuQD+7o3Z6+S9QIDAQAB\n"
+    "-----END PUBLIC KEY-----\n"
+};
+#endif
+
+//Helper Fn for Base64 Decode, pass out the unsigned char** with the caller responsibility to free out
+int unbase64(char *input, unsigned char **out)
+{
+#ifdef RBX_BUILD_CRYPT
+    BIO *b64, *bmem;
+
+    // base64 encoding is longer than the original 'string'
+    int length = strlen(input);
+    unsigned char *buffer = (unsigned char *)malloc(length);
+
+    b64 = BIO_new(BIO_f_base64());
+    BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL);
+
+    bmem = BIO_new_mem_buf(input, length);
+    bmem = BIO_push(b64, bmem);
+
+    length = BIO_read(bmem, buffer, length);
+    buffer[length] = 0;
+
+    BIO_free_all(bmem);
+
+    *out = buffer; // caller frees
+    return length;
+#else
+    return 0;
+#endif
+}
+
+// verify that the plaintext message is matching signature (base64 encoded)
+int verifyMessage(char* message, char* sig_b64)
+{
+#ifdef RBX_BUILD_CRYPT
+    SHA_CTX sha_ctx = { 0 };
+    unsigned char digest[SHA_DIGEST_LENGTH];
+    int rc = 1;
+
+    //SHA1((unsigned char*)message, strlen(message), digest);
+    rc = SHA1_Init(&sha_ctx);
+    if (1 != rc)
+        throw RBX::runtime_error("Error during SHA_Init");
+
+    rc = SHA1_Update(&sha_ctx, (unsigned char*)message, strlen(message));
+    if (1 != rc)
+        throw RBX::runtime_error("Error during SHA_Update");
+
+    rc = SHA1_Final(digest, &sha_ctx);
+    if (1 != rc)
+        throw RBX::runtime_error("Error during SHA_Final");
+
+    unsigned char* signature;
+    int length = unbase64(sig_b64, &signature);
+
+    // WARNING: no error checking for brevity
+    BIO* bio = BIO_new_mem_buf(publicKey, sizeof(publicKey));
+
+    RSA* rsa_key = 0;
+    rsa_key = PEM_read_bio_RSA_PUBKEY(bio, NULL, NULL, NULL);
+
+    int ret = RSA_verify(NID_sha1, digest, SHA_DIGEST_LENGTH, signature, length, rsa_key);
+
+    ERR_print_errors_fp(stdout);
+
+    RSA_free(rsa_key);
+    BIO_free(bio);
+    free(signature);
+
+    return ret;
+#else
+    return 1;
+#endif
+}
+} // namespace
+
+namespace RBX
+{
+	Crypt::Crypt()
+	{
+	}
+	
+	Crypt::~Crypt()
+	{
+	}
+		
+	//Crypt implementation with RSA security using SHA1 algorithm for signature verification.
+	void Crypt::verifySignatureBase64(std::string messageStr, std::string signatureStr)
+	{
+		if (!verifyMessage((char*)messageStr.c_str(), (char*)signatureStr.c_str()))
+			throw std::runtime_error("");  // message hidden on purpose - prevent reverse engineering
+	}
+			
+} // namespace RBX