[CT437]: Add Assignment 2

year4/semester2/CT437/assignments/assignment2/HeaderTemplate-2.h

@@ -0,0 +1,9 @@
+/* Create a header file for each source code file using the same name, but with a "*.h" extension. */
+/* Keep it in the same folder as the source code file, and include it via #include "file.h" */
+
+#ifndef FILENAME /* This symbolic name is unique and should match the file name. */
+#define FILENAME /* This expression makes sure that this header file is only included once. */
+
+/* Add all your function prototypes, macros, #defines, etc. below. */
+
+#endif

year4/semester2/CT437/assignments/assignment2/tutorial/andrew_keyfile.pem

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+-----BEGIN ENCRYPTED PRIVATE KEY-----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+-----END ENCRYPTED PRIVATE KEY-----

year4/semester2/CT437/assignments/assignment2/tutorial/openssl_encrypt.c

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+// Compile this code via gcc -o openssl_encrypt openssl_encrypt.c -lssl -lcrypto
+
+#include <openssl/evp.h>
+#include <openssl/aes.h>
+#include <openssl/err.h>
+#include <string.h>
+#include <stdio.h>
+
+void handleErrors(void) {
+    ERR_print_errors_fp(stderr);
+    abort();
+}
+
+int encrypt(unsigned char *plaintext, int plaintext_len, unsigned char *key,
+            unsigned char *iv, unsigned char *ciphertext) {
+    EVP_CIPHER_CTX *ctx;
+    int len;
+    int ciphertext_len;
+
+    if(!(ctx = EVP_CIPHER_CTX_new())) handleErrors();
+
+    if(1 != EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv))
+        handleErrors();
+
+    if(1 != EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len))
+        handleErrors();
+    ciphertext_len = len;
+
+    if(1 != EVP_EncryptFinal_ex(ctx, ciphertext + len, &len)) handleErrors();
+    ciphertext_len += len;
+
+    EVP_CIPHER_CTX_free(ctx);
+
+    return ciphertext_len;
+}
+
+int main(void) {
+    unsigned char *key = (unsigned char *)"01234567890123456789012345678901";
+    unsigned char *iv = (unsigned char *)"0123456789012345";
+    unsigned char *plaintext = (unsigned char *)"This is a secret message";
+    unsigned char ciphertext[128];
+
+    int ciphertext_len = encrypt(plaintext, strlen((char *)plaintext), key, iv, ciphertext);
+
+    printf("PLaintext: %s\n", plaintext);
+    printf("Ciphertext:\n");
+    BIO_dump_fp(stdout, (const char *)ciphertext, ciphertext_len);
+
+    return 0;
+}

year4/semester2/CT437/assignments/assignment2/tutorial/openssl_encrypt_decrypt_long.c

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+// Compile this code via gcc -o openssl_encrypt_long openssl_encrypt_long.c -lssl -lcrypto
+
+#include <openssl/evp.h>
+#include <openssl/aes.h>
+#include <openssl/err.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+void handleErrors(void) {
+    ERR_print_errors_fp(stderr);
+    abort();
+}
+
+int encrypt(unsigned char *plaintext, int plaintext_len, unsigned char *key,
+            unsigned char *iv, unsigned char *ciphertext) {
+    EVP_CIPHER_CTX *ctx;
+    int len;
+    int ciphertext_len;
+
+    if(!(ctx = EVP_CIPHER_CTX_new())) handleErrors();
+
+    if(1 != EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv))
+        handleErrors();
+
+    if(1 != EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len))
+        handleErrors();
+    ciphertext_len = len;
+
+    if(1 != EVP_EncryptFinal_ex(ctx, ciphertext + len, &len)) handleErrors();
+    ciphertext_len += len;
+
+    EVP_CIPHER_CTX_free(ctx);
+
+    return ciphertext_len;
+}
+
+int decrypt(unsigned char *ciphertext, int ciphertext_len, unsigned char *key,
+            unsigned char *iv, unsigned char *plaintext) {
+    EVP_CIPHER_CTX *ctx;
+    int len;
+    int plaintext_len;
+
+    if(!(ctx = EVP_CIPHER_CTX_new())) handleErrors();
+
+    if(1 != EVP_DecryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv))
+        handleErrors();
+
+    if(1 != EVP_DecryptUpdate(ctx, plaintext, &len, ciphertext, ciphertext_len))
+        handleErrors();
+    plaintext_len = len;
+
+    if(1 != EVP_DecryptFinal_ex(ctx, plaintext + len, &len)) handleErrors();
+    plaintext_len += len;
+
+    EVP_CIPHER_CTX_free(ctx);
+
+    return plaintext_len;
+}
+
+
+int main(void) {
+	const int LEN = 100000000;
+    unsigned char *key = (unsigned char *)"01234567890123456789012345678901";
+    unsigned char *iv = (unsigned char *)"0123456789012345";
+    unsigned char *plaintext = (unsigned char *) malloc(LEN);
+    unsigned char *ciphertext = (unsigned char *) malloc(LEN + 100);
+
+    int decryptedtext_len;
+    unsigned char *decryptedtext = (unsigned char *) malloc(LEN + 100);
+
+	memset(plaintext, 0x72, LEN);
+    plaintext[LEN - 1] = 0;
+    printf("Start\n");
+    int ciphertext_len = encrypt(plaintext, strlen((char *)plaintext), key, iv, ciphertext);
+
+    decryptedtext_len = decrypt(ciphertext, ciphertext_len, key, iv, decryptedtext);
+    decryptedtext[decryptedtext_len - 1] = '\0';
+
+    printf("End\n");
+
+    // Print the first 100 characters of the original and decoded text.
+    printf("Original plaintext: %.100s\nDecoded ciphertext: %.100s\n", plaintext, decryptedtext);
+
+    return 0;
+}

year4/semester2/CT437/assignments/assignment2/tutorial/public_key.txt

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+-----BEGIN PUBLIC KEY-----
+MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDm822B5kbggiD6c3T5z1/V+Io3
+HgrVyHnd9mLHHJtv6gryfqwBYylSMabJnET85f4HYa/JtW0D4m8keQGNPxlRSqOD
+caNrwVYYQ27O2TEB+9Lqkr6bUv1ChVgO2D0nwYDCA5a50qWLKZrvp/xSOb3l8owk
+JFcgvsmffjm7sSM+DQIDAQAB
+-----END PUBLIC KEY-----