goboxcrypt

This is a simple library for the encryption and decryption of plain text in Go/Golang. This library was written on pure go without any packages. All code is implemented in 269 lines.

Usage

There are two algorythms for encryption in this library:

1. Encryption with an S-box lookup table
2. Encryption with P-box permutation.

Encrypt_Sbox

This function splits plain text strings on an 8-bit list. Then from the 8-bit block make 2 nibble. Example: char "s" is equal to 01110011 bits (UTF8 s == 115 or 01110011). From these bits, we can make two nibbles: 0111 and 0011. Then with the AES S-box table, we can get a new value from this nibble. The first nibble (0111) we use for rows in this table and the second nibble(0011) is for columns, the result for block "s" is 8f hex or 143 decimal or 10001111 bits. After this step, the new swapped block is XORed with a round key. This process repeated for each block and then for all rounds. When all steps were done each block was converted into the hex value, this is how we get a cipher text.

Library API for Sbox algo:

plainText := "Hello World and Distributed Lab team! My name is Den'ys. I wrote these encryption scripts. Look at README to understand how! :D"
key := "3c45886ac87483a37dbc34ce7bf1fc99917a5ea8c9ba0ebab8a2d42a84d18c98"

cipher_Sbox := goboxcrypt.Encrypt_Sbox(plainText, key)
backtoPlane := goboxcrypt.Decrypt_Sbox(cipher_Sbox, key)
// cipher ->  b64f6e6e65c0e3658d6e68c0370668c08acad3b78dca83aab74f68c03d3783c0b74f374542c0ff21c00637454fc0cad3c08a4f069f21d36bc081c0fc8d65b74fc0b7804fd34fc04f061b8d2132b7ca6506c0d31b8dca32b7d36bc03d6565c4c037b7c0e2e4f78affe4c0b765c0aa06684f8dd3b7370668c08065fc42c07c8a

For the S-box table, I used the original AES S-box lookup table:

	00	01	02	03	04	05	06	07	08	09	0a	0b	0c	0d	0e	0f
00	63	7c	77	7b	f2	6b	6f	c5	30	01	67	2b	fe	d7	ab	76
10	ca	82	c9	7d	fa	59	47	f0	ad	d4	a2	af	9c	a4	72	c0
20	b7	fd	93	26	36	3f	f7	cc	34	a5	e5	f1	71	d8	31	15
30	04	c7	23	c3	18	96	05	9a	07	12	80	e2	eb	27	b2	75
40	09	83	2c	1a	1b	6e	5a	a0	52	3b	d6	b3	29	e3	2f	84
50	53	d1	00	ed	20	fc	b1	5b	6a	cb	be	39	4a	4c	58	cf
60	d0	ef	aa	fb	43	4d	33	85	45	f9	02	7f	50	3c	9f	a8
70	51	a3	40	8f	92	9d	38	f5	bc	b6	da	21	10	ff	f3	d2
80	cd	0c	13	ec	5f	97	44	17	c4	a7	7e	3d	64	5d	19	73
90	60	81	4f	dc	22	2a	90	88	46	ee	b8	14	de	5e	0b	db
a0	e0	32	3a	0a	49	06	24	5c	c2	d3	ac	62	91	95	e4	79
b0	e7	c8	37	6d	8d	d5	4e	a9	6c	56	f4	ea	65	7a	ae	08
c0	ba	78	25	2e	1c	a6	b4	c6	e8	dd	74	1f	4b	bd	8b	8a
d0	70	3e	b5	66	48	03	f6	0e	61	35	57	b9	86	c1	1d	9e
e0	e1	f8	98	11	69	d9	8e	94	9b	1e	87	e9	ce	55	28	df
f0	8c	a1	89	0d	bf	e6	42	68	41	99	2d	0f	b0	54	bb	16

The column is determined by the least significant nibble, and the row by the most significant nibble. For example, the value 9a16 is converted into b816.

Inverse S-box table

	00	01	02	03	04	05	06	07	08	09	0a	0b	0c	0d	0e	0f
00	52	09	6a	d5	30	36	a5	38	bf	40	a3	9e	81	f3	d7	fb
10	7c	e3	39	82	9b	2f	ff	87	34	8e	43	44	c4	de	e9	cb
20	54	7b	94	32	a6	c2	23	3d	ee	4c	95	0b	42	fa	c3	4e
30	08	2e	a1	66	28	d9	24	b2	76	5b	a2	49	6d	8b	d1	25
40	72	f8	f6	64	86	68	98	16	d4	a4	5c	cc	5d	65	b6	92
50	6c	70	48	50	fd	ed	b9	da	5e	15	46	57	a7	8d	9d	84
60	90	d8	ab	00	8c	bc	d3	0a	f7	e4	58	05	b8	b3	45	06
70	d0	2c	1e	8f	ca	3f	0f	02	c1	af	bd	03	01	13	8a	6b
80	3a	91	11	41	4f	67	dc	ea	97	f2	cf	ce	f0	b4	e6	73
90	96	ac	74	22	e7	ad	35	85	e2	f9	37	e8	1c	75	df	6e
a0	47	f1	1a	71	1d	29	c5	89	6f	b7	62	0e	aa	18	be	1b
b0	fc	56	3e	4b	c6	d2	79	20	9a	db	c0	fe	78	cd	5a	f4
c0	1f	dd	a8	33	88	07	c7	31	b1	12	10	59	27	80	ec	5f
d0	60	51	7f	a9	19	b5	4a	0d	2d	e5	7a	9f	93	c9	9c	ef
e0	a0	e0	3b	4d	ae	2a	f5	b0	c8	eb	bb	3c	83	53	99	61
f0	17	2b	04	7e	ba	77	d6	26	e1	69	14	63	55	21	0c	7d

Encrypt_Pbox

For this algorithm I've used a similar technique as Sbox but instead substitution table there is permutation box with the next rule for each nibble:

Library API for Pbox algo:

	plainText := "Hello World and Distributed Lab team! My name is Den'ys. I wrote these encryption scripts. Look at README to understand how! :D"
	key := "3c45886ac87483a37dbc34ce7bf1fc99917a5ea8c9ba0ebab8a2d42a84d18c98"

	cipher_Pbox := goboxcrypt.Encrypt_Pbox(plainText, key)
	backtoPlane = goboxcrypt.Decrypt_Pbox(cipher_Pbox, key)
	fmt.Println("cipher -> ", cipher_Pbox)
	fmt.Println("plain text -> ", backtoPlane)
	/*
		cipher ->  db5c5a5a504ff450775a5e4f5d525e4fde59757e7759577c7e5c5e4fda5d574f7e5c5d584d4fd8794f525d585c4f59754fde5c52447975424fd94f7477507e5c4f7e5b5c755c4f5c525577797f7e5950524f755577597f7e75424fda5050514f5d7e4ff7dcddded8dc4f7e504f7c525e5c77757e5d525e4f5b50744d4f63de
		plain text ->  Hello World and Distributed Lab team! My name is Den'ys. I wrote these encryption scripts. Look at README to understand how! :D
	*/