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var Buffer = require('safe-buffer').Buffer
var MD5 = require('md5.js')
/* eslint-disable camelcase */
function EVP_BytesToKey (password, salt, keyBits, ivLen) {
if (!Buffer.isBuffer(password)) password = Buffer.from(password, 'binary')
if (salt) {
if (!Buffer.isBuffer(salt)) salt = Buffer.from(salt, 'binary')
if (salt.length !== 8) throw new RangeError('salt should be Buffer with 8 byte length')
}
var keyLen = keyBits / 8
var key = Buffer.alloc(keyLen)
var iv = Buffer.alloc(ivLen || 0)
var tmp = Buffer.alloc(0)
while (keyLen > 0 || ivLen > 0) {
var hash = new MD5()
hash.update(tmp)
hash.update(password)
if (salt) hash.update(salt)
tmp = hash.digest()
var used = 0
if (keyLen > 0) {
var keyStart = key.length - keyLen
used = Math.min(keyLen, tmp.length)
tmp.copy(key, keyStart, 0, used)
keyLen -= used
}
if (used < tmp.length && ivLen > 0) {
var ivStart = iv.length - ivLen
var length = Math.min(ivLen, tmp.length - used)
tmp.copy(iv, ivStart, used, used + length)
ivLen -= length
}
}
tmp.fill(0)
return { key: key, iv: iv }
}
module.exports = EVP_BytesToKey