imba/polyfills/crypto/esm/lib/browserify-aes/modes/cfb1.js

Intuitive and powerful language for building webapps that fly

function encryptByte(self, byteParam, decrypt) {
    var pad;
    var i = -1;
    var len = 8;
    var out = 0;
    var bit, value;
    while (++i < len) {
        pad = self._cipher.encryptBlock(self._prev);
        bit = (byteParam & (1 << (7 - i))) ? 0x80 : 0;
        value = pad[0] ^ bit;
        out += ((value & 0x80) >> (i % 8));
        self._prev = shiftIn(self._prev, decrypt ? bit : value);
    }
    return out;
}
function shiftIn(buffer, value) {
    var len = buffer.length;
    var i = -1;
    var out = Buffer.allocUnsafe(buffer.length);
    buffer = Buffer.concat([buffer, Buffer.from([value])]);
    while (++i < len) {
        out[i] = buffer[i] << 1 | buffer[i + 1] >> (7);
    }
    return out;
}
export const encrypt = function (self, chunk, decrypt) {
    var len = chunk.length;
    var out = Buffer.allocUnsafe(len);
    var i = -1;
    while (++i < len) {
        out[i] = encryptByte(self, chunk[i], decrypt);
    }
    return out;
};