133 lines
3.6 KiB
JavaScript
133 lines
3.6 KiB
JavaScript
const { crypto_stream_chacha20_ietf, crypto_stream_chacha20_ietf_xor_ic } = require('./crypto_stream_chacha20')
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const { crypto_verify_16 } = require('./crypto_verify')
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const Poly1305 = require('./poly1305.js')
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const assert = require('nanoassert')
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const crypto_aead_chacha20poly1305_ietf_KEYBYTES = 32
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const crypto_aead_chacha20poly1305_ietf_NSECBYTES = 0
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const crypto_aead_chacha20poly1305_ietf_NPUBBYTES = 12
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const crypto_aead_chacha20poly1305_ietf_ABYTES = 16
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const crypto_aead_chacha20poly1305_ietf_MESSAGEBYTES_MAX = Number.MAX_SAFE_INTEGER
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const _pad0 = Buffer.alloc(16)
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function crypto_aead_chacha20poly1305_ietf_encrypt(c, m, ad, nsec, npub, k) {
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var ret
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assert(m.length <= crypto_aead_chacha20poly1305_ietf_MESSAGEBYTES_MAX, 'message is too large')
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ret = crypto_aead_chacha20poly1305_ietf_encrypt_detached(c, c.subarray(m.length), m, ad, nsec, npub, k)
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if (ret === 0) {
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return m.length + crypto_aead_chacha20poly1305_ietf_ABYTES
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}
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return ret
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}
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function crypto_aead_chacha20poly1305_ietf_encrypt_detached(c, mac, m, ad, nsec, npub, k) {
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const block0 = new Uint8Array(64)
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var slen = Buffer.alloc(8)
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crypto_stream_chacha20_ietf(block0, npub, k)
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const poly = new Poly1305(block0)
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block0.fill(0)
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poly.update(ad, 0, ad.length)
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poly.update(_pad0, 0, (0x10 - ad.length) & 0xf)
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crypto_stream_chacha20_ietf_xor_ic(c, m, npub, 1, k)
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poly.update(c, 0, m.length)
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poly.update(_pad0, 0, (0x10 - m.length) & 0xf)
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write64LE(slen, ad.length)
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poly.update(slen, 0, slen.length)
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write64LE(slen, m.length)
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poly.update(slen, 0, slen.length)
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poly.finish(mac, 0)
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slen.fill(0)
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return crypto_aead_chacha20poly1305_ietf_ABYTES
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}
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function crypto_aead_chacha20poly1305_ietf_decrypt (m, nsec, c, ad, npub, k) {
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var ret = -1
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if (c.length >= crypto_aead_chacha20poly1305_ietf_ABYTES) {
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ret = crypto_aead_chacha20poly1305_ietf_decrypt_detached(
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m, nsec,
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c.subarray(0, c.length - crypto_aead_chacha20poly1305_ietf_ABYTES),
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c.subarray(c.length - crypto_aead_chacha20poly1305_ietf_ABYTES),
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ad, npub, k)
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}
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if (ret === 0) {
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return c.length - crypto_aead_chacha20poly1305_ietf_ABYTES
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}
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return ret;
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}
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function crypto_aead_chacha20poly1305_ietf_decrypt_detached (m, nsec, c, mac, ad, npub, k) {
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const block0 = new Uint8Array(64)
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const slen = Buffer.alloc(8)
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const computed_mac = Buffer.alloc(crypto_aead_chacha20poly1305_ietf_ABYTES)
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var mlen
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var ret
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crypto_stream_chacha20_ietf(block0, npub, k)
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const poly = new Poly1305(block0)
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block0.fill(0)
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poly.update(ad, 0, ad.length)
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poly.update(_pad0, 0, (0x10 - ad.length) & 0xf)
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mlen = c.length
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poly.update(c, 0, mlen)
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poly.update(_pad0, 0, (0x10 - mlen) & 0xf)
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write64LE(slen, ad.length)
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poly.update(slen, 0, slen.length)
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write64LE(slen, mlen)
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poly.update(slen, 0, slen.length)
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poly.finish(computed_mac, 0)
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assert(computed_mac.length === 16)
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ret = crypto_verify_16(computed_mac, 0, mac, 0)
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computed_mac.fill(0)
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slen.fill(0)
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if (ret !== 0) {
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m.fill(0)
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return -1
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}
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crypto_stream_chacha20_ietf_xor_ic(m, c, npub, 1, k)
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return 0
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}
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function write64LE (buf, int) {
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buf.fill(0, 0, 8)
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buf.writeUInt32LE(int & 0xffffffff)
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buf.writeUInt32LE((int >> 32) & 0xffffffff)
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}
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module.exports = {
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crypto_aead_chacha20poly1305_ietf_encrypt,
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crypto_aead_chacha20poly1305_ietf_encrypt_detached,
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crypto_aead_chacha20poly1305_ietf_decrypt,
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crypto_aead_chacha20poly1305_ietf_decrypt_detached,
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crypto_aead_chacha20poly1305_ietf_ABYTES,
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crypto_aead_chacha20poly1305_ietf_KEYBYTES,
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crypto_aead_chacha20poly1305_ietf_NPUBBYTES,
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crypto_aead_chacha20poly1305_ietf_NSECBYTES
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}
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d_chacha20poly1305_ietf_NSECBYTES
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}
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