Geremia G / Crypto

Fork of François Berder Crypto, fixed AES CBC and small rework

Dependents:   AES_example shaun_larada Smartage

Fork of Crypto by Francois Berder

cipher/RC4.cpp@16:4399e2e6260b, 2015-01-28 (annotated)

Committer:
Geremia
Date:
Wed Jan 28 17:55:13 2015 +0000
Revision:
16:4399e2e6260b
Parent:
8:a090264e9b2d 
AES: bugfixed CBC, added PCBC (i could add CFB and OFB if needed), added public setIV(), moved keyExpansion() to public, in and out buffers can be the same

Who changed what in which revision?

UserRevisionLine numberNew contents of line
feb11 0:7a1237bd2d13 1 #include "RC4.h"
feb11 0:7a1237bd2d13 2
feb11 0:7a1237bd2d13 3 RC4::RC4(uint8_t *key, uint8_t keyLength):
feb11 8:a090264e9b2d 4 StreamCipher(),
feb11 0:7a1237bd2d13 5 s(),
feb11 0:7a1237bd2d13 6 i(0),
feb11 0:7a1237bd2d13 7 j(0)
feb11 0:7a1237bd2d13 8 {
feb11 0:7a1237bd2d13 9 for(int k = 0; k < 256; ++k)
feb11 0:7a1237bd2d13 10 s[k] = k;
feb11 0:7a1237bd2d13 11 int l = 0;
feb11 0:7a1237bd2d13 12 for(int k = 0; k < 256; ++k)
feb11 0:7a1237bd2d13 13 {
feb11 0:7a1237bd2d13 14 l = (l + s[k] + key[k % keyLength]) % 256;
feb11 0:7a1237bd2d13 15 uint8_t tmp = s[l];
feb11 0:7a1237bd2d13 16 s[l] = s[k];
feb11 0:7a1237bd2d13 17 s[k] = tmp;
feb11 0:7a1237bd2d13 18 }
feb11 0:7a1237bd2d13 19 }
feb11 0:7a1237bd2d13 20
feb11 8:a090264e9b2d 21 uint8_t RC4::encryptByte(uint8_t in)
feb11 0:7a1237bd2d13 22 {
feb11 0:7a1237bd2d13 23 ++i;
feb11 0:7a1237bd2d13 24 j += s[i];
feb11 0:7a1237bd2d13 25 uint8_t tmp = s[i];
feb11 0:7a1237bd2d13 26 s[i] = s[j];
feb11 0:7a1237bd2d13 27 s[j] = tmp;
feb11 0:7a1237bd2d13 28 uint8_t c = s[(s[i]+s[j])%256];
feb11 8:a090264e9b2d 29 return in^c;
feb11 0:7a1237bd2d13 30 }
feb11 0:7a1237bd2d13 31
feb11 8:a090264e9b2d 32 uint8_t RC4::decryptByte(uint8_t in)
feb11 0:7a1237bd2d13 33 {
feb11 8:a090264e9b2d 34 return encryptByte(in);
feb11 0:7a1237bd2d13 35 }