Post-quantum cryptanalysis of PeaZip encryption methods

Impact of quantum computing on encryption

Security of encryption and hashing algorithm rely on computational unfeasibility of solving some classes of hard mathematical problems in reasonable time and with finite / cost effective computation resources.
Quantum computing, based on quantum bits (qbits) which can exist in superpositions of states, provides breakthrough performances in solving some classes of hard mathematical problems over classic computing methods, based on binary digital electronic architecture; the impact of this performance improvement must be carefully evaluated to assess security of existing cipher and hash functions in a scenario where quantum computers will be available.

Quantum computing and symmetric-key encryption algorithms

To preserve data secrecy, symmetric-key cryptography rely on a shared secret element (password / passphrase, keyfile, biometric data, or combinations of more factors as in two-factor authentication) between two or more parties.
The need to share this element, needed by receiver for decryption, is the main disadvantage of (secret) symmetric-key cryptography solutions over public-key cryptography solutions.

Algorithms in use in PeaZip
PeaZip currently supports only symmetic-key encryption mechanisms, using password / passphrase and optionally two-factor authentication (password / passphrase + key file), which under current understandings are quite secure against attacks by arbitrarily sized quantum computers.

Attacks on symmetric encryption algorithms using quantum computers

Grover's quantum algorithm is the best-possible known attack for most of current generation symmetric encryption algorithms (and hash functions), providing - for NP-complete problems - a quadratic speed-up over a classic computing based brute-force search.

Security of symmetric encryption algorithms from quantum computing methods

IUnder those premises, in example AES 256 bit could be considered equivalent in security (when arbitrarily large quantum computers are available, using Grover algorithm over the 256 bit key space) to AES 128 bit (for classic computers, using classic computing brute-force over the 128 bit key space) - which means 256 bit key size is considered secure even in case of quantum computing attack, under current understandings.
Same holds true for other symmetric key ciphers like DES, Blowfish, Twofish, and Serpent.
While a quadratic speed-up (providing a sufficiently powerful quantum computer is available) is an huge performance improvement, it is nowhere near a complete breakthrough as polynomial time solution provided by Shor's algorithm is for public-key encryption systems, so post-quantum symmetric cryptography is thought to not need to differ significantly from the current generation.

Read more about symmetic-key encryption algorithms supported by PeaZip: Rijndael/AES (implemented as AES128 and AES256 in 7Z, ARC, RAR, PEA, and ZIP standards), and Twofish and Serpent ciphers (implemented for ARC and PEA standards).
Read more about cryptographically secure hash function

Learn more: Grover's algorithm

Quantum computing and public-key encryption algorithms

Public-key encryption systems are currently extremely popular, as they simplify key exchange task: anyone can encrypt a message using a public key released by a receiver, but only receiver's private key can decrypt messages protected by its public key.
Unfortunately, most ones of currently popular public-key algorithms are susceptible of being efficiently broken by a large enough quantum computer.

Attacks on public key encryption algorithms using quantum computing

Experimental public-key algorithms relying on problems not efficiently simplified by Shor's algorithm or other quantum algorithms, being both reasonably safe under classic computing and quantum computing -based attacks, is currently an active research topic in cryptography.
PeaZip currently does not support public-key encryption methods, only symmetric (secret) -key encryption - keys (passwords, keyfiles) needs to be privately, securely shared with receiver for decryption to take place.
Learn more: Shor's algorithm .

Quantum cryptography

Learn more about PEA encryption utility, how to protect files and folders, how to securely share files with email or cloud, and how to try to open unreadable files.

Synopsis: Post-quantum computing cryptanalisys of cryptography methods used in PeaZip. Security of AES, Twofish and Serpent symmetric key encryption attacked by Grover algorithm. Impact of quantum computing attacks on public key encryption methids with Shor algorithm. Secure key size for quantum computing attacks.

Topics: impact of quantum computing on symmetyric key cryptography algorithms employed in PeaZip

PeaZip > FAQ > Post-quantum computing cryptography analysis of PeaZip