149 lines
4.5 KiB
V
149 lines
4.5 KiB
V
module blowfish
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// expand_key performs a key expansion on the given Blowfish cipher.
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pub fn expand_key(key []byte, mut bf Blowfish) {
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mut j := 0
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for i := 0; i < 18; i++ {
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mut d := u32(0)
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for k := 0; k < 4; k++ {
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d = d << 8 | u32(key[j])
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j++
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if j >= key.len {
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j = 0
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}
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}
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bf.p[i] ^= d
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}
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mut l := u32(0)
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mut r := u32(0)
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for i := 0; i < 18; i += 2 {
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arr := setup_tables(l, r, mut bf)
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bf.p[i], bf.p[i + 1] = arr[0], arr[1]
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}
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for i := 0; i < 256; i += 2 {
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arr := setup_tables(l, r, mut bf)
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bf.s[0][i], bf.s[0][i + 1] = arr[0], arr[1]
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}
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for i := 0; i < 256; i += 2 {
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arr := setup_tables(l, r, mut bf)
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bf.s[1][i], bf.s[1][i + 1] = arr[0], arr[1]
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}
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for i := 0; i < 256; i += 2 {
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arr := setup_tables(l, r, mut bf)
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bf.s[2][i], bf.s[2][i + 1] = arr[0], arr[1]
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}
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for i := 0; i < 256; i += 2 {
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arr := setup_tables(l, r, mut bf)
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bf.s[3][i], bf.s[3][i + 1] = arr[0], arr[1]
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}
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}
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// expand_key_with_salt using salt to expand the key.
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pub fn expand_key_with_salt(key []byte, salt []byte, mut bf Blowfish) {
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mut j := 0
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for i := 0; i < 18; i++ {
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bf.p[i] ^= get_next_word(key, &j)
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}
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j = 0
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mut l := u32(0)
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mut r := u32(0)
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for i := 0; i < 18; i += 2 {
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l ^= get_next_word(key, &j)
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r ^= get_next_word(key, &j)
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arr := setup_tables(l, r, mut bf)
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bf.p[i], bf.p[i + 1] = arr[0], arr[1]
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}
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for i := 0; i < 256; i += 2 {
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l ^= get_next_word(key, &j)
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r ^= get_next_word(key, &j)
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arr := setup_tables(l, r, mut bf)
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bf.s[0][i], bf.s[0][i + 1] = arr[0], arr[1]
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}
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for i := 0; i < 256; i += 2 {
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l ^= get_next_word(key, &j)
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r ^= get_next_word(key, &j)
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arr := setup_tables(l, r, mut bf)
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bf.s[1][i], bf.s[1][i + 1] = arr[0], arr[1]
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}
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for i := 0; i < 256; i += 2 {
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l ^= get_next_word(key, &j)
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r ^= get_next_word(key, &j)
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arr := setup_tables(l, r, mut bf)
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bf.s[2][i], bf.s[2][i + 1] = arr[0], arr[1]
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}
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for i := 0; i < 256; i += 2 {
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l ^= get_next_word(key, &j)
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r ^= get_next_word(key, &j)
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arr := setup_tables(l, r, mut bf)
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bf.s[3][i], bf.s[3][i + 1] = arr[0], arr[1]
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}
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}
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// setup_tables sets up the Blowfish cipher's pi and substitution tables.
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fn setup_tables(l u32, r u32, mut bf Blowfish) []u32 {
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mut xl := l
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mut xr := r
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xl ^= bf.p[0]
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xr ^= ((bf.s[0][byte(xl >> 24)] + bf.s[1][byte(xl >> 16)]) ^ bf.s[2][byte(xl >> 8)]) +
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(bf.s[3][byte(xl)] ^ bf.p[1])
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xl ^= ((bf.s[0][byte(xr >> 24)] + bf.s[1][byte(xr >> 16)]) ^ bf.s[2][byte(xr >> 8)]) +
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(bf.s[3][byte(xr)] ^ bf.p[2])
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xr ^= ((bf.s[0][byte(xl >> 24)] + bf.s[1][byte(xl >> 16)]) ^ bf.s[2][byte(xl >> 8)]) +
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(bf.s[3][byte(xl)] ^ bf.p[3])
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xl ^= ((bf.s[0][byte(xr >> 24)] + bf.s[1][byte(xr >> 16)]) ^ bf.s[2][byte(xr >> 8)]) +
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(bf.s[3][byte(xr)] ^ bf.p[4])
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xr ^= ((bf.s[0][byte(xl >> 24)] + bf.s[1][byte(xl >> 16)]) ^ bf.s[2][byte(xl >> 8)]) +
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(bf.s[3][byte(xl)] ^ bf.p[5])
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xl ^= ((bf.s[0][byte(xr >> 24)] + bf.s[1][byte(xr >> 16)]) ^ bf.s[2][byte(xr >> 8)]) +
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(bf.s[3][byte(xr)] ^ bf.p[6])
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xr ^= ((bf.s[0][byte(xl >> 24)] + bf.s[1][byte(xl >> 16)]) ^ bf.s[2][byte(xl >> 8)]) +
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(bf.s[3][byte(xl)] ^ bf.p[7])
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xl ^= ((bf.s[0][byte(xr >> 24)] + bf.s[1][byte(xr >> 16)]) ^ bf.s[2][byte(xr >> 8)]) +
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(bf.s[3][byte(xr)] ^ bf.p[8])
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xr ^= ((bf.s[0][byte(xl >> 24)] + bf.s[1][byte(xl >> 16)]) ^ bf.s[2][byte(xl >> 8)]) +
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(bf.s[3][byte(xl)] ^ bf.p[9])
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xl ^= ((bf.s[0][byte(xr >> 24)] + bf.s[1][byte(xr >> 16)]) ^ bf.s[2][byte(xr >> 8)]) +
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(bf.s[3][byte(xr)] ^ bf.p[10])
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xr ^= ((bf.s[0][byte(xl >> 24)] + bf.s[1][byte(xl >> 16)]) ^ bf.s[2][byte(xl >> 8)]) +
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(bf.s[3][byte(xl)] ^ bf.p[11])
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xl ^= ((bf.s[0][byte(xr >> 24)] + bf.s[1][byte(xr >> 16)]) ^ bf.s[2][byte(xr >> 8)]) +
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(bf.s[3][byte(xr)] ^ bf.p[12])
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xr ^= ((bf.s[0][byte(xl >> 24)] + bf.s[1][byte(xl >> 16)]) ^ bf.s[2][byte(xl >> 8)]) +
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(bf.s[3][byte(xl)] ^ bf.p[13])
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xl ^= ((bf.s[0][byte(xr >> 24)] + bf.s[1][byte(xr >> 16)]) ^ bf.s[2][byte(xr >> 8)]) +
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(bf.s[3][byte(xr)] ^ bf.p[14])
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xr ^= ((bf.s[0][byte(xl >> 24)] + bf.s[1][byte(xl >> 16)]) ^ bf.s[2][byte(xl >> 8)]) +
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(bf.s[3][byte(xl)] ^ bf.p[15])
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xl ^= ((bf.s[0][byte(xr >> 24)] + bf.s[1][byte(xr >> 16)]) ^ bf.s[2][byte(xr >> 8)]) +
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(bf.s[3][byte(xr)] ^ bf.p[16])
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xr ^= bf.p[17]
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res := [xl, xr]
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return res
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}
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// get_next_word returns the next big-endian u32 value from the byte
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// slice at the given position in a circular manner, updating the position.
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fn get_next_word(b []byte, pos &int) u32 {
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mut w := u32(0)
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mut j := 0
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unsafe {
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j = *pos
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}
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for i := 0; i < 4; i++ {
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w = w << 8 | u32(b[j])
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j++
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if j >= b.len {
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j = 0
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}
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}
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unsafe {
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*pos = j
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}
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return w
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}
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