RIPEMD-256 — криптографическая хеш-функция , разработанная Хансом Доббертином, Антоном Боселаерсом и Бартом Принилом в 1996 году. Размер хэша — 256 бит. Размер блока входных данных — 512 бит. RIPEMD-256 является развитием RIPEMD-128 и предназначен для приложений, которые требуют более длинного хэша и нуждаются в большей безопасности, чем приложения уровня RIPEMD-128. Уязвимостей данного алгоритма на текущий момент не обнаружено.

Пример

RIPEMD-256("") = 02ba4c4e5f8ecd1877fc52d64d30e37a2d9774fb1e5d026380ae0168e3c5522d

RIPEMD-256(«а») = f9333e45d857f5d90a91bab70a1eba0cfb1be4b0783c9acfcd883a9134692925

Псевдокод для RIPEMD-256

 RIPEMD-256: определения 

 нелинейные функции: exor, mux, -, mux 

 f(j, x, y, z) = x XOR y XOR z (0 <= j <= 15) f(j, x, y, z) = (x AND y) OR (NOT(x) AND z) (16 <= j <= 31) f(j, x, y, z) = (x OR NOT(y)) XOR z (32 <= j <= 47) f(j, x, y, z) = (x AND z) OR (y AND NOT(z)) (48 <= j <= 63) 

 константы (шестнадцатеричные) 

 K(j) = 0x00000000 (0 <= j <= 15) K(j) = 0x5A827999 (16 <= j <= 31) int(2**30 x sqrt(2)) K(j) = 0x6ED9EBA1 (32 <= j <= 47) int(2**30 x sqrt(3)) K(j) = 0x8F1BBCDC (48 <= j <= 63) int(2**30 x sqrt(5)) K'(j) = 0x50A28BE6 (0 <= j <= 15) int(2**30 x cbrt(2)) K'(j) = 0x5C4DD124 (16 <= j <= 31) int(2**30 x cbrt(3)) K'(j) = 0x6D703EF3 (32 <= j <= 47) int(2**30 x cbrt(5)) K'(j) = 0x00000000 (48 <= j <= 63) 

 выбор слов в сообщении 

 r(j) = j (0 <= j <= 15) r(16..31) = 7, 4, 13, 1, 10, 6, 15, 3, 12, 0, 9, 5, 2, 14, 11, 8 r(32..47) = 3, 10, 14, 4, 9, 15, 8, 1, 2, 7, 0, 6, 13, 11, 5, 12 r(48..63) = 1, 9, 11, 10, 0, 8, 12, 4, 13, 3, 7, 15, 14, 5, 6, 2 r'(0..15) = 5, 14, 7, 0, 9, 2, 11, 4, 13, 6, 15, 8, 1, 10, 3, 12 r'(16..31)= 6, 11, 3, 7, 0, 13, 5, 10, 14, 15, 8, 12, 4, 9, 1, 2 r'(32..47)= 15, 5, 1, 3, 7, 14, 6, 9, 11, 8, 12, 2, 10, 0, 4, 13 r'(48..63)= 8, 6, 4, 1, 3, 11, 15, 0, 5, 12, 2, 13, 9, 7, 10, 14 

 сумма для левого поворота 

 s(0..15) = 11, 14, 15, 12, 5, 8, 7, 9, 11, 13, 14, 15, 6, 7, 9, 8 s(16..31) = 7, 6, 8, 13, 11, 9, 7, 15, 7, 12, 15, 9, 11, 7, 13, 12 s(32..47) = 11, 13, 6, 7, 14, 9, 13, 15, 14, 8, 13, 6, 5, 12, 7, 5 s(48..63) = 11, 12, 14, 15, 14, 15, 9, 8, 9, 14, 5, 6, 8, 6, 5, 12 s'(0..15) = 8, 9, 9, 11, 13, 15, 15, 5, 7, 7, 8, 11, 14, 14, 12, 6 s'(16..31)= 9, 13, 15, 7, 12, 8, 9, 11, 7, 7, 12, 7, 6, 15, 13, 11 s'(32..47)= 9, 7, 15, 11, 8, 6, 6, 14, 12, 13, 5, 14, 13, 13, 7, 5 s'(48..63)= 15, 5, 8, 11, 14, 14, 6, 14, 6, 9, 12, 9, 12, 5, 15, 8 

 первоначалыные значения (шестнадцатиричные) 

 h0 = 0x67452301; h1 = 0xEFCDAB89; h2 = 0x98BADCFE; h3 = 0x10325476; h4 = 0x76543210; h5 = 0xFEDCBA98; h6 = 0x89ABCDEF; h7 = 0x01234567; 

 RIPEMD-256: псевдокод 

 for i := 0 to t-1 { A := h0; B := h1; C := h2; D = h3; A' := h4; B' := h5; C' := h6; D' = h7; for j := 0 to 63 { T := rol_s(j)(A [+] f(j, B, C, D) [+] X[i][r(j)] [+] K(j)); A := D; D := C; C := B; B := T; T := rol_s'(j)(A' [+] f(63-j, B', C', D') [+] X[i][r'(j)] [+] K'(j)); A' := D'; D' := C'; C' := B'; B' := T; if j == 15 { T := A; A := A'; A' := T; } else if j == 31 { T := B; B := B'; B' := T; } else if j == 47 { T := C; C := C'; C' := T; } else if j == 63 { T := D; D := D'; D' := T; } } h0 := h0 + A; h1 := h1 + B; h2 := h2 + C; h3 := h3 + D; h4 := h4 + A'; h5 := h5 + B'; h6 := h6 + C'; h7 := h7 + D'; } 

См. также

• RIPEMD-128
• RIPEMD-160
• RIPEMD-320