cipher
Let an agent explain ciphers and their kinds, relay classical and modern ciphers and their security status from cryptography references, describe how ciphers are evaluated, and distinguish ciphers from codes and from cryptographic protocols.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify
Researched by: Claude
Purpose and description
Let an agent explain ciphers and their kinds, relay classical and modern ciphers and their security status from cryptography references, describe how ciphers are evaluated, and distinguish ciphers from codes and from cryptographic protocols.
An algorithm for encrypting and decrypting information by transforming plaintext into ciphertext under a key, from classical ciphers such as substitution and transposition systems including historical schemes like the Templar cipher and music ciphers, through machine ciphers, to modern block and stream ciphers such as AES and ChaCha20 and government suites such as NSA Suite A; ciphers are judged by security, with weak and broken ciphers no longer fit for use, and are distinguished from codes, which replace words or phrases.
What it is for: Encrypting information.
It can be explain kinds of cipher; relay classical and modern examples; describe security evaluation; distinguish from codes and protocols.
Distinguishing features
Key-dependent transformation
Symmetric and asymmetric forms
Security evaluation
Long history
What it looks like
Not a visible object; algorithms and ciphertext.
Physical character
AES standardised: 2001 year - FIPS 197
AES key sizes: 128, 192, 256 bits
How it is recognised
Algorithm transforming plaintext under a key
Classical, machine, block and stream ciphers; NSA Suite A; weak and broken ciphers; Templar and music ciphers
Codes replace words; hashes are one-way; protocols combine ciphers with other primitives
Related models
is a kind of - in registry terms
is a kind of - in registry terms, though cryptographers distinguish the two
is a kind of - in registry terms
is used in - with other primitives
In practice
Families and kinds
classical substitution and transposition ciphers including Caesar, Vigenere and the Templar cipher
music and other novelty ciphers
rotor and machine ciphers such as Enigma
modern block ciphers such as AES
stream ciphers such as ChaCha20
asymmetric ciphers such as RSA
government cipher suites such as NSA Suite A and Suite B
weak and broken ciphers such as DES and RC4
Identifiers
FIPS 197 AES
Standards and regulation
NIST and ISO/IEC cipher standards
National security classifications of cipher suites
Export controls on cryptography in some countries
Guidance deprecating weak ciphers
Failure modes and hazards
Using broken or weak ciphers
Poor key management
Agents providing attack guidance against systems without authorisation
Confusing ciphers with codes
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.cipher-person
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.
Understand What a cipher is.
Definition.
Definition
Definition.
Definition
Definition.
- What is a cipher, and how does it differ from a code, a hash and a protocol? definition
- Is the question about ciphers in general, a specific cipher or a protocol? boundary
Kinds
Kinds.
Kinds
Kinds.
- What are substitution, transposition, block, stream and asymmetric ciphers? definition
- Which entry fits the specific kind? action
Examples Classical and modern ciphers.
Sources.
Classical
Classical ciphers.
Classical
Classical.
- How do Caesar, Vigenere, the Templar cipher and music ciphers work, and how are they broken? provenance
- Which references are standard? provenance
Modern
Modern ciphers.
Modern
Modern.
- How do AES, ChaCha20 and RSA work in general terms, and what are NSA Suite A and Suite B? provenance
- Which entry fits the specific cipher? action
Security Security.
Science.
Evaluation
Evaluating ciphers.
Evaluation
Evaluation.
- How are ciphers analysed, and what makes a cipher weak or broken? provenance
- Is the question seeking to attack systems the user does not own, which the model does not support? boundary
Practice
Practice.
Practice
Practice.
- What ciphers and modes do standards recommend today, and which are deprecated? action
- Which sources are cited? provenance
Context History and future.
Context.
History
History.
History
History.
- How did ciphers develop from antiquity through Enigma to modern cryptography? provenance
- Which entry fits the history of cryptography? action
Future
Post-quantum.
Future
Future.
- How does quantum computing affect ciphers, and what post-quantum standards exist? provenance
- Which entry fits post-quantum cryptography? action
What the second pass must settle
- Should classical cipher and block cipher be separate primary entries?
- How should standards be linked?
- The registry entry has merged aliases naming government suites and novelty ciphers; should they be split off?