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#Macbook encryption algorithm full
#Macbook encryption algorithm plus
#Macbook encryption algorithm series

To work with 16-bit words (meaning 4 inputs instead of 2 for the 64-bit block size), IDEA uses the Lai–Massey scheme twice in parallel, with the two parallel round functions being interwoven with each other. IDEA uses a key-dependent half-round function. XOR is used for both subtraction and addition. The overall structure of IDEA follows the Lai–Massey scheme.

Multiplication modulo 2 16 + 1, where the all-zero word (0x0000) in inputs is interpreted as 2 16, and 2 16 in output is interpreted as the all-zero word (0x0000) (denoted by a red circled dot ⊙).Īfter the 8 rounds comes a final “half-round”, the output transformation illustrated below (the swap of the middle two values cancels out the swap at the end of the last round, so that there is no net swap):.

#Macbook encryption algorithm plus

Addition modulo 2 16 (denoted with a green boxed plus ⊞).Bitwise XOR (exclusive OR) (denoted with a blue circled plus ⊕).In more detail, these operators, which all deal with 16-bit quantities, are: IDEA derives much of its security by interleaving operations from different groups - modular addition and multiplication, and bitwise eXclusive OR (XOR) - which are algebraically "incompatible" in some sense. The processes for encryption and decryption are similar.

#Macbook encryption algorithm series

IDEA operates on 64-bit blocks using a 128-bit key and consists of a series of 8 identical transformations (a round, see the illustration) and an output transformation (the half-round). IDEA is an optional algorithm in the OpenPGP standard. IDEA was used in Pretty Good Privacy (PGP) v2.0 and was incorporated after the original cipher used in v1.0, BassOmatic, was found to be insecure.

The last patents expired in 2012, and IDEA is now patent-free and thus completely free for all uses. The cipher was patented in a number of countries but was freely available for non-commercial use. The cipher was designed under a research contract with the Hasler Foundation, which became part of Ascom-Tech AG. IDEA is a minor revision of an earlier cipher Proposed Encryption Standard (PES). The algorithm was intended as a replacement for the Data Encryption Standard (DES). In cryptography, the International Data Encryption Algorithm ( IDEA), originally called Improved Proposed Encryption Standard ( IPES), is a symmetric-key block cipher designed by James Massey of ETH Zurich and Xuejia Lai and was first described in 1991.

#Macbook encryption algorithm full

This attack is computationally faster than a full brute-force attack, though not, as of 2013, computationally feasible. The key can be recovered with a computational complexity of 2 126.1 using narrow bicliques.