fix: broken image links have been fixed

_posts/Lecture Notes/Internet Security/2023-09-10-security-intro.md

@@ -155,7 +155,7 @@ There are many ways of achieving security.
 
 ### Basics of a Cryptosystem
 
-![is-01-cryptosystem.png](../../../assets/img/posts/Lecture%20Notes/Internet%20Security/is-01-cryptosystem.png#)
+![is-01-cryptosystem.png](/assets/img/posts/Lecture%20Notes/Internet%20Security/is-01-cryptosystem.png#)
 
 - A **message** in *plaintext* is given to an **encryption algorithm**.
 - The encryption algorithm uses an **encryption key** to create a *ciphertext*.

_posts/Lecture Notes/Internet Security/2023-09-18-symmetric-key-cryptography-2.md

@@ -63,7 +63,7 @@ $$
 
 #### The Feistel Function
 
-![is-03-feistel-function.png](../../../assets/img/posts/Lecture%20Notes/Internet%20Security/is-03-feistel-function.png#)
+![is-03-feistel-function.png](/assets/img/posts/Lecture%20Notes/Internet%20Security/is-03-feistel-function.png#)
 
 The Feistel function takes $32$ bit data and divides it into eight $4$ bit chunks. Each chunk is expanded to $6$ bits using a P-box. Now, we have 48 bits of data, so apply XOR with the key for this round. Next, each $6$-bit block is compressed back to $4$ bits using a S-box. Finally, there is a (straight) permutation at the end, resulting in $32$ bit data.
 
@@ -179,7 +179,7 @@ AES, DES use fixed block size for encryption. How do we encrypt longer messages?
 
 ### Electronic Codebook Mode (ECB)
 
-![is-03-ecb-encryption.png](../../../assets/img/posts/Lecture%20Notes/Internet%20Security/is-03-ecb-encryption.png#)
+![is-03-ecb-encryption.png](/assets/img/posts/Lecture%20Notes/Internet%20Security/is-03-ecb-encryption.png#)
 
 - Codebook is a mapping table.
 - For the $i$-th plaintext block, we use key $k$ to encrypt and obtain the $i$-th ciphertext block.
@@ -198,7 +198,7 @@ Since the same key is used for all blocks, once a mapping from plaintext to ciph
 
 ### Cipher Block Chaining Mode (CBC)
 
-![is-03-cbc-encryption.png](../../../assets/img/posts/Lecture%20Notes/Internet%20Security/is-03-cbc-encryption.png#)
+![is-03-cbc-encryption.png](/assets/img/posts/Lecture%20Notes/Internet%20Security/is-03-cbc-encryption.png#)
 
 - Two identical messages produce to different ciphertexts.
 	- This prevents chosen plaintext attacks
@@ -248,7 +248,7 @@ Since the same key is used for all blocks, once a mapping from plaintext to ciph
 
 ### Cipher Feedback Mode (CFB)
 
-![is-03-cfb-encryption.png](../../../assets/img/posts/Lecture%20Notes/Internet%20Security/is-03-cfb-encryption.png#)
+![is-03-cfb-encryption.png](/assets/img/posts/Lecture%20Notes/Internet%20Security/is-03-cfb-encryption.png#)
 
 - The message is treated as a stream of bits; similar to stream cipher
 - **Result of the encryption is fed to the next stage.**
@@ -283,7 +283,7 @@ Since the same key is used for all blocks, once a mapping from plaintext to ciph
 
 ### Output Feedback Mode (OFB)
 
-![is-03-ofb-encryption.png](../../../assets/img/posts/Lecture%20Notes/Internet%20Security/is-03-ofb-encryption.png#)
+![is-03-ofb-encryption.png](/assets/img/posts/Lecture%20Notes/Internet%20Security/is-03-ofb-encryption.png#)
 
 - Very similar to stream cipher.
 - Initialization vector is used as a seed to generate the key stream.
@@ -316,7 +316,7 @@ Since the same key is used for all blocks, once a mapping from plaintext to ciph
 
 ### Counter Mode (CTR)
 
-![is-03-ctr-encryption.png](../../../assets/img/posts/Lecture%20Notes/Internet%20Security/is-03-ctr-encryption.png#)
+![is-03-ctr-encryption.png](/assets/img/posts/Lecture%20Notes/Internet%20Security/is-03-ctr-encryption.png#)
 
 - Without chaining, we use a counter (typically incremented by $1$).
 	- Counter starts from the initialization vector.

_posts/Lecture Notes/Internet Security/2023-10-16-pki.md

@@ -83,7 +83,7 @@ We have a root CA at the top. Then there are issuing CAs below. We usually reque
 
 ### Certificate Validation
 
-![is-08-certificate-validation.png](../../../assets/img/posts/Lecture%20Notes/Internet%20Security/is-08-certificate-validation.png#)[^1]
+![is-08-certificate-validation.png](/assets/img/posts/Lecture%20Notes/Internet%20Security/is-08-certificate-validation.png#)[^1]
 
 Since we have a hierarchy of CAs, certificate validation must also follow the hierarchy. When we receive a certificate, it is highly likely to be signed by an non-root CA.
 

_posts/Lecture Notes/Internet Security/2023-10-18-tls.md

@@ -146,7 +146,7 @@ Here's how the client and the server establishes a connection using the TLS hand
 > 3. Use the server's public key to share a secret.
 > 4. Both parties generate a symmetric key from the shared secret.
 
-![is-09-tls-handshake.png](../../../assets/img/posts/Lecture%20Notes/Internet%20Security/is-09-tls-handshake.png#)[^1]
+![is-09-tls-handshake.png](/assets/img/posts/Lecture%20Notes/Internet%20Security/is-09-tls-handshake.png#)[^1]
 
 - `ServerKeyExchange`, `ClientKeyExchange` is optional. Used sometimes if Diffie-Hellman is used.
 - The actual messages and process differ for each protocol and ciphers used.