crypto.blowfish: add doc comments for the public API (#12609)

pull/12618/head
Taillook 2021-11-30 05:19:52 +09:00 committed by GitHub
parent 14424100e8
commit bbc47562b3
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 21 additions and 12 deletions

View File

@ -1,5 +1,6 @@
module blowfish module blowfish
// expand_key performs a key expansion on the given Blowfish cipher.
pub fn expand_key(key []byte, mut bf Blowfish) { pub fn expand_key(key []byte, mut bf Blowfish) {
mut j := 0 mut j := 0
for i := 0; i < 18; i++ { for i := 0; i < 18; i++ {
@ -17,28 +18,29 @@ pub fn expand_key(key []byte, mut bf Blowfish) {
mut l := u32(0) mut l := u32(0)
mut r := u32(0) mut r := u32(0)
for i := 0; i < 18; i += 2 { for i := 0; i < 18; i += 2 {
arr := encrypt_block(l, r, mut bf) arr := setup_tables(l, r, mut bf)
bf.p[i], bf.p[i + 1] = arr[0], arr[1] bf.p[i], bf.p[i + 1] = arr[0], arr[1]
} }
for i := 0; i < 256; i += 2 { for i := 0; i < 256; i += 2 {
arr := encrypt_block(l, r, mut bf) arr := setup_tables(l, r, mut bf)
bf.s[0][i], bf.s[0][i + 1] = arr[0], arr[1] bf.s[0][i], bf.s[0][i + 1] = arr[0], arr[1]
} }
for i := 0; i < 256; i += 2 { for i := 0; i < 256; i += 2 {
arr := encrypt_block(l, r, mut bf) arr := setup_tables(l, r, mut bf)
bf.s[1][i], bf.s[1][i + 1] = arr[0], arr[1] bf.s[1][i], bf.s[1][i + 1] = arr[0], arr[1]
} }
for i := 0; i < 256; i += 2 { for i := 0; i < 256; i += 2 {
arr := encrypt_block(l, r, mut bf) arr := setup_tables(l, r, mut bf)
bf.s[2][i], bf.s[2][i + 1] = arr[0], arr[1] bf.s[2][i], bf.s[2][i + 1] = arr[0], arr[1]
} }
for i := 0; i < 256; i += 2 { for i := 0; i < 256; i += 2 {
arr := encrypt_block(l, r, mut bf) arr := setup_tables(l, r, mut bf)
bf.s[3][i], bf.s[3][i + 1] = arr[0], arr[1] bf.s[3][i], bf.s[3][i + 1] = arr[0], arr[1]
} }
} }
// expand_key_with_salt using salt to expand the key.
pub fn expand_key_with_salt(key []byte, salt []byte, mut bf Blowfish) { pub fn expand_key_with_salt(key []byte, salt []byte, mut bf Blowfish) {
mut j := 0 mut j := 0
for i := 0; i < 18; i++ { for i := 0; i < 18; i++ {
@ -52,37 +54,38 @@ pub fn expand_key_with_salt(key []byte, salt []byte, mut bf Blowfish) {
for i := 0; i < 18; i += 2 { for i := 0; i < 18; i += 2 {
l ^= get_next_word(key, &j) l ^= get_next_word(key, &j)
r ^= get_next_word(key, &j) r ^= get_next_word(key, &j)
arr := encrypt_block(l, r, mut bf) arr := setup_tables(l, r, mut bf)
bf.p[i], bf.p[i + 1] = arr[0], arr[1] bf.p[i], bf.p[i + 1] = arr[0], arr[1]
} }
for i := 0; i < 256; i += 2 { for i := 0; i < 256; i += 2 {
l ^= get_next_word(key, &j) l ^= get_next_word(key, &j)
r ^= get_next_word(key, &j) r ^= get_next_word(key, &j)
arr := encrypt_block(l, r, mut bf) arr := setup_tables(l, r, mut bf)
bf.s[0][i], bf.s[0][i + 1] = arr[0], arr[1] bf.s[0][i], bf.s[0][i + 1] = arr[0], arr[1]
} }
for i := 0; i < 256; i += 2 { for i := 0; i < 256; i += 2 {
l ^= get_next_word(key, &j) l ^= get_next_word(key, &j)
r ^= get_next_word(key, &j) r ^= get_next_word(key, &j)
arr := encrypt_block(l, r, mut bf) arr := setup_tables(l, r, mut bf)
bf.s[1][i], bf.s[1][i + 1] = arr[0], arr[1] bf.s[1][i], bf.s[1][i + 1] = arr[0], arr[1]
} }
for i := 0; i < 256; i += 2 { for i := 0; i < 256; i += 2 {
l ^= get_next_word(key, &j) l ^= get_next_word(key, &j)
r ^= get_next_word(key, &j) r ^= get_next_word(key, &j)
arr := encrypt_block(l, r, mut bf) arr := setup_tables(l, r, mut bf)
bf.s[2][i], bf.s[2][i + 1] = arr[0], arr[1] bf.s[2][i], bf.s[2][i + 1] = arr[0], arr[1]
} }
for i := 0; i < 256; i += 2 { for i := 0; i < 256; i += 2 {
l ^= get_next_word(key, &j) l ^= get_next_word(key, &j)
r ^= get_next_word(key, &j) r ^= get_next_word(key, &j)
arr := encrypt_block(l, r, mut bf) arr := setup_tables(l, r, mut bf)
bf.s[3][i], bf.s[3][i + 1] = arr[0], arr[1] bf.s[3][i], bf.s[3][i + 1] = arr[0], arr[1]
} }
} }
fn encrypt_block(l u32, r u32, mut bf Blowfish) []u32 { // setup_tables sets up the Blowfish cipher's pi and substitution tables.
fn setup_tables(l u32, r u32, mut bf Blowfish) []u32 {
mut xl := l mut xl := l
mut xr := r mut xr := r
xl ^= bf.p[0] xl ^= bf.p[0]
@ -123,6 +126,8 @@ fn encrypt_block(l u32, r u32, mut bf Blowfish) []u32 {
return res return res
} }
// get_next_word returns the next big-endian u32 value from the byte
// slice at the given position in a circular manner, updating the position.
fn get_next_word(b []byte, pos &int) u32 { fn get_next_word(b []byte, pos &int) u32 {
mut w := u32(0) mut w := u32(0)
mut j := 0 mut j := 0

View File

@ -6,6 +6,8 @@ pub mut:
s [4][256]u32 s [4][256]u32
} }
// new_cipher creates and returns a new Blowfish cipher.
// The key argument should be the Blowfish key, from 1 to 56 bytes.
pub fn new_cipher(key []byte) ?Blowfish { pub fn new_cipher(key []byte) ?Blowfish {
mut bf := Blowfish{} mut bf := Blowfish{}
unsafe { vmemcpy(&bf.p[0], &p[0], int(sizeof(bf.p))) } unsafe { vmemcpy(&bf.p[0], &p[0], int(sizeof(bf.p))) }
@ -18,6 +20,7 @@ pub fn new_cipher(key []byte) ?Blowfish {
return bf return bf
} }
// new_salted_cipher returns a new Blowfish cipher that folds a salt into its key schedule.
pub fn new_salted_cipher(key []byte, salt []byte) ?Blowfish { pub fn new_salted_cipher(key []byte, salt []byte) ?Blowfish {
if salt.len == 0 { if salt.len == 0 {
return new_cipher(key) return new_cipher(key)
@ -32,10 +35,11 @@ pub fn new_salted_cipher(key []byte, salt []byte) ?Blowfish {
return bf return bf
} }
// encrypt encrypts the 8-byte buffer src using the key k and stores the result in dst.
pub fn (mut bf Blowfish) encrypt(mut dst []byte, src []byte) { pub fn (mut bf Blowfish) encrypt(mut dst []byte, src []byte) {
l := u32(src[0]) << 24 | u32(src[1]) << 16 | u32(src[2]) << 8 | u32(src[3]) l := u32(src[0]) << 24 | u32(src[1]) << 16 | u32(src[2]) << 8 | u32(src[3])
r := u32(src[4]) << 24 | u32(src[5]) << 16 | u32(src[6]) << 8 | u32(src[7]) r := u32(src[4]) << 24 | u32(src[5]) << 16 | u32(src[6]) << 8 | u32(src[7])
arr := encrypt_block(l, r, mut bf) arr := setup_tables(l, r, mut bf)
dst[0], dst[1], dst[2], dst[3] = byte(arr[0] >> 24), byte(arr[0] >> 16), byte(arr[0] >> 8), byte(arr[0]) dst[0], dst[1], dst[2], dst[3] = byte(arr[0] >> 24), byte(arr[0] >> 16), byte(arr[0] >> 8), byte(arr[0])
dst[4], dst[5], dst[6], dst[7] = byte(arr[1] >> 24), byte(arr[1] >> 16), byte(arr[1] >> 8), byte(arr[1]) dst[4], dst[5], dst[6], dst[7] = byte(arr[1] >> 24), byte(arr[1] >> 16), byte(arr[1] >> 8), byte(arr[1])
} }