Resource Sheet

Steganography(Image)

There exist various methods to hide information in an image . Some chose to hide it in the metadata(description that provides additional information about the image like location , date & time , author info. , editing history etc.) , some chose to hide it in the bits of the file's data.
So in order to reveal such information various tools can be used to extract such hidden information(flags in your case:)

• exiftool
• strings
• steghide
• binwalk
• zsteg

Online tool : aperisolve

Ciphers

1. Caesar Cipher: Shifts each letter in the plaintext by a fixed number of positions in the alphabet. Most famous is shifting by 13 alphabets.
2. Vigenère Cipher: Uses a keyword to shift letters in the plaintext by varying amounts.
3. XOR Cipher: Encrypts data by applying the XOR operation with a key.

Encodings

1. Base64: Encodes binary data into ASCII text using a set of 64 characters for safe transmission. Usually ends with 1 to 3 =s .
2. Base58: Similar to Base64 but omits confusing characters, used in Bitcoin addresses.
3. Base32: Encodes binary data into ASCII text using a set of 32 characters, often used for QR codes.

Encryption Algorithms

1. RSA (Rivest-Shamir-Adleman) : An asymmetric encryption algorithm that uses a public key for encryption and a private key for decryption, widely used for secure data transmission and digital signatures.

Some more theorems and tools you can go through for the challenges :

1. Sagemath (or online alternative cocalc)
2. 

Maybe useful

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