CRYPTOGRAPHY UPDATED SCRIPT 2026
PRACTICE SOLUTIONS GRADED A+
●● Cryptanalysis. Answer: Analyzing those algorithms with the aim of
breaching security
●● Confidentiality. Answer: Only authorized people can see the
information
●● Integrity. Answer: The information has not been altered or tampered
with
●● Coding theory vs cryptography. Answer: Coding theory assumes
random noise and focuses on error detection/correction. Cryptography
assumes an active, malicious adversary and focuses on keeping data
confidential and unaltered even when someone is trying to break it.
●● Steganography. Answer: Hide the existence of the message so it is
not noticed.
●● Cryptography. Answer: Hide the meaning of the message so it is
unintelligible even if intercepted.
, ●● Both steganography and cryptography. Answer: Are orthogonal and
can be combined; an encrypted message can also be hidden
●● Secure Channel. Answer: Provides confidentiality integrity and
authenticity between sender & receiver.
●● Eavesdropping. Answer: The person intercepts or alters messages in
transit
●● Protection. Answer: Encryption ensures intercepted ciphertext is
useless without the key.
●● Kerckhoff's Law. Answer: The cryptanalyst knows all details of
encryption & decryption except the secret keys An encryption scheme
should remain secure even if everything but the key is public.
- security must rely on key secrecy not algorithm secrecy
- keys are easy to change; algorithms are not
_ public, standardized algorithms benefit from scrutiny and
compatibility
→ this principle underpins modern cryptography: publish the algorithm,
protect the key, and still remain secure against informed adversaries.
●● Why kerckhoff's law. Answer: 1. Easy to keep a short key secret than
a complex algorithm, especially at scale
PRACTICE SOLUTIONS GRADED A+
●● Cryptanalysis. Answer: Analyzing those algorithms with the aim of
breaching security
●● Confidentiality. Answer: Only authorized people can see the
information
●● Integrity. Answer: The information has not been altered or tampered
with
●● Coding theory vs cryptography. Answer: Coding theory assumes
random noise and focuses on error detection/correction. Cryptography
assumes an active, malicious adversary and focuses on keeping data
confidential and unaltered even when someone is trying to break it.
●● Steganography. Answer: Hide the existence of the message so it is
not noticed.
●● Cryptography. Answer: Hide the meaning of the message so it is
unintelligible even if intercepted.
, ●● Both steganography and cryptography. Answer: Are orthogonal and
can be combined; an encrypted message can also be hidden
●● Secure Channel. Answer: Provides confidentiality integrity and
authenticity between sender & receiver.
●● Eavesdropping. Answer: The person intercepts or alters messages in
transit
●● Protection. Answer: Encryption ensures intercepted ciphertext is
useless without the key.
●● Kerckhoff's Law. Answer: The cryptanalyst knows all details of
encryption & decryption except the secret keys An encryption scheme
should remain secure even if everything but the key is public.
- security must rely on key secrecy not algorithm secrecy
- keys are easy to change; algorithms are not
_ public, standardized algorithms benefit from scrutiny and
compatibility
→ this principle underpins modern cryptography: publish the algorithm,
protect the key, and still remain secure against informed adversaries.
●● Why kerckhoff's law. Answer: 1. Easy to keep a short key secret than
a complex algorithm, especially at scale
