40 lines
1.5 KiB
JavaScript
40 lines
1.5 KiB
JavaScript
var assert = require('nanoassert')
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var randombytes_buf = require('./randombytes').randombytes_buf
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var blake2b = require('blake2b')
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module.exports.crypto_kdf_PRIMITIVE = 'blake2b'
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module.exports.crypto_kdf_BYTES_MIN = 16
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module.exports.crypto_kdf_BYTES_MAX = 64
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module.exports.crypto_kdf_CONTEXTBYTES = 8
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module.exports.crypto_kdf_KEYBYTES = 32
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function STORE64_LE(dest, int) {
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var mul = 1
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var i = 0
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dest[0] = int & 0xFF
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while (++i < 8 && (mul *= 0x100)) {
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dest[i] = (int / mul) & 0xFF
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}
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}
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module.exports.crypto_kdf_derive_from_key = function crypto_kdf_derive_from_key (subkey, subkey_id, ctx, key) {
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assert(subkey.length >= module.exports.crypto_kdf_BYTES_MIN, 'subkey must be at least crypto_kdf_BYTES_MIN')
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assert(subkey_id >= 0 && subkey_id <= 0x1fffffffffffff, 'subkey_id must be safe integer')
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assert(ctx.length >= module.exports.crypto_kdf_CONTEXTBYTES, 'context must be at least crypto_kdf_CONTEXTBYTES')
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var ctx_padded = new Uint8Array(blake2b.PERSONALBYTES)
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var salt = new Uint8Array(blake2b.SALTBYTES)
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ctx_padded.set(ctx, 0, module.exports.crypto_kdf_CONTEXTBYTES)
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STORE64_LE(salt, subkey_id)
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var outlen = Math.min(subkey.length, module.exports.crypto_kdf_BYTES_MAX)
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blake2b(outlen, key.subarray(0, module.exports.crypto_kdf_KEYBYTES), salt, ctx_padded, true)
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.final(subkey)
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}
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module.exports.crypto_kdf_keygen = function crypto_kdf_keygen (out) {
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assert(out.length >= module.exports.crypto_kdf_KEYBYTES, 'out.length must be crypto_kdf_KEYBYTES')
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randombytes_buf(out.subarray(0, module.exports.crypto_kdf_KEYBYTES))
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}
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