Blowfish
A
S
a
package com.thealgorithms.ciphers;
/*
* Java program for Blowfish Algorithm
* Wikipedia: https://en.wikipedia.org/wiki/Blowfish_(cipher)
*
* Author: Akshay Dubey (https://github.com/itsAkshayDubey)
*
* */
public class Blowfish {
// Initializing substitution boxes
String[][] S = {
{
"d1310ba6",
"98dfb5ac",
"2ffd72db",
"d01adfb7",
"b8e1afed",
"6a267e96",
"ba7c9045",
"f12c7f99",
"24a19947",
"b3916cf7",
"0801f2e2",
"858efc16",
"636920d8",
"71574e69",
"a458fea3",
"f4933d7e",
"0d95748f",
"728eb658",
"718bcd58",
"82154aee",
"7b54a41d",
"c25a59b5",
"9c30d539",
"2af26013",
"c5d1b023",
"286085f0",
"ca417918",
"b8db38ef",
"8e79dcb0",
"603a180e",
"6c9e0e8b",
"b01e8a3e",
"d71577c1",
"bd314b27",
"78af2fda",
"55605c60",
"e65525f3",
"aa55ab94",
"57489862",
"63e81440",
"55ca396a",
"2aab10b6",
"b4cc5c34",
"1141e8ce",
"a15486af",
"7c72e993",
"b3ee1411",
"636fbc2a",
"2ba9c55d",
"741831f6",
"ce5c3e16",
"9b87931e",
"afd6ba33",
"6c24cf5c",
"7a325381",
"28958677",
"3b8f4898",
"6b4bb9af",
"c4bfe81b",
"66282193",
"61d809cc",
"fb21a991",
"487cac60",
"5dec8032",
"ef845d5d",
"e98575b1",
"dc262302",
"eb651b88",
"23893e81",
"d396acc5",
"0f6d6ff3",
"83f44239",
"2e0b4482",
"a4842004",
"69c8f04a",
"9e1f9b5e",
"21c66842",
"f6e96c9a",
"670c9c61",
"abd388f0",
"6a51a0d2",
"d8542f68",
"960fa728",
"ab5133a3",
"6eef0b6c",
"137a3be4",
"ba3bf050",
"7efb2a98",
"a1f1651d",
"39af0176",
"66ca593e",
"82430e88",
"8cee8619",
"456f9fb4",
"7d84a5c3",
"3b8b5ebe",
"e06f75d8",
"85c12073",
"401a449f",
"56c16aa6",
"4ed3aa62",
"363f7706",
"1bfedf72",
"429b023d",
"37d0d724",
"d00a1248",
"db0fead3",
"49f1c09b",
"075372c9",
"80991b7b",
"25d479d8",
"f6e8def7",
"e3fe501a",
"b6794c3b",
"976ce0bd",
"04c006ba",
"c1a94fb6",
"409f60c4",
"5e5c9ec2",
"196a2463",
"68fb6faf",
"3e6c53b5",
"1339b2eb",
"3b52ec6f",
"6dfc511f",
"9b30952c",
"cc814544",
"af5ebd09",
"bee3d004",
"de334afd",
"660f2807",
"192e4bb3",
"c0cba857",
"45c8740f",
"d20b5f39",
"b9d3fbdb",
"5579c0bd",
"1a60320a",
"d6a100c6",
"402c7279",
"679f25fe",
"fb1fa3cc",
"8ea5e9f8",
"db3222f8",
"3c7516df",
"fd616b15",
"2f501ec8",
"ad0552ab",
"323db5fa",
"fd238760",
"53317b48",
"3e00df82",
"9e5c57bb",
"ca6f8ca0",
"1a87562e",
"df1769db",
"d542a8f6",
"287effc3",
"ac6732c6",
"8c4f5573",
"695b27b0",
"bbca58c8",
"e1ffa35d",
"b8f011a0",
"10fa3d98",
"fd2183b8",
"4afcb56c",
"2dd1d35b",
"9a53e479",
"b6f84565",
"d28e49bc",
"4bfb9790",
"e1ddf2da",
"a4cb7e33",
"62fb1341",
"cee4c6e8",
"ef20cada",
"36774c01",
"d07e9efe",
"2bf11fb4",
"95dbda4d",
"ae909198",
"eaad8e71",
"6b93d5a0",
"d08ed1d0",
"afc725e0",
"8e3c5b2f",
"8e7594b7",
"8ff6e2fb",
"f2122b64",
"8888b812",
"900df01c",
"4fad5ea0",
"688fc31c",
"d1cff191",
"b3a8c1ad",
"2f2f2218",
"be0e1777",
"ea752dfe",
"8b021fa1",
"e5a0cc0f",
"b56f74e8",
"18acf3d6",
"ce89e299",
"b4a84fe0",
"fd13e0b7",
"7cc43b81",
"d2ada8d9",
"165fa266",
"80957705",
"93cc7314",
"211a1477",
"e6ad2065",
"77b5fa86",
"c75442f5",
"fb9d35cf",
"ebcdaf0c",
"7b3e89a0",
"d6411bd3",
"ae1e7e49",
"00250e2d",
"2071b35e",
"226800bb",
"57b8e0af",
"2464369b",
"f009b91e",
"5563911d",
"59dfa6aa",
"78c14389",
"d95a537f",
"207d5ba2",
"02e5b9c5",
"83260376",
"6295cfa9",
"11c81968",
"4e734a41",
"b3472dca",
"7b14a94a",
"1b510052",
"9a532915",
"d60f573f",
"bc9bc6e4",
"2b60a476",
"81e67400",
"08ba6fb5",
"571be91f",
"f296ec6b",
"2a0dd915",
"b6636521",
"e7b9f9b6",
"ff34052e",
"c5855664",
"53b02d5d",
"a99f8fa1",
"08ba4799",
"6e85076a",
},
{
"4b7a70e9",
"b5b32944",
"db75092e",
"c4192623",
"ad6ea6b0",
"49a7df7d",
"9cee60b8",
"8fedb266",
"ecaa8c71",
"699a17ff",
"5664526c",
"c2b19ee1",
"193602a5",
"75094c29",
"a0591340",
"e4183a3e",
"3f54989a",
"5b429d65",
"6b8fe4d6",
"99f73fd6",
"a1d29c07",
"efe830f5",
"4d2d38e6",
"f0255dc1",
"4cdd2086",
"8470eb26",
"6382e9c6",
"021ecc5e",
"09686b3f",
"3ebaefc9",
"3c971814",
"6b6a70a1",
"687f3584",
"52a0e286",
"b79c5305",
"aa500737",
"3e07841c",
"7fdeae5c",
"8e7d44ec",
"5716f2b8",
"b03ada37",
"f0500c0d",
"f01c1f04",
"0200b3ff",
"ae0cf51a",
"3cb574b2",
"25837a58",
"dc0921bd",
"d19113f9",
"7ca92ff6",
"94324773",
"22f54701",
"3ae5e581",
"37c2dadc",
"c8b57634",
"9af3dda7",
"a9446146",
"0fd0030e",
"ecc8c73e",
"a4751e41",
"e238cd99",
"3bea0e2f",
"3280bba1",
"183eb331",
"4e548b38",
"4f6db908",
"6f420d03",
"f60a04bf",
"2cb81290",
"24977c79",
"5679b072",
"bcaf89af",
"de9a771f",
"d9930810",
"b38bae12",
"dccf3f2e",
"5512721f",
"2e6b7124",
"501adde6",
"9f84cd87",
"7a584718",
"7408da17",
"bc9f9abc",
"e94b7d8c",
"ec7aec3a",
"db851dfa",
"63094366",
"c464c3d2",
"ef1c1847",
"3215d908",
"dd433b37",
"24c2ba16",
"12a14d43",
"2a65c451",
"50940002",
"133ae4dd",
"71dff89e",
"10314e55",
"81ac77d6",
"5f11199b",
"043556f1",
"d7a3c76b",
"3c11183b",
"5924a509",
"f28fe6ed",
"97f1fbfa",
"9ebabf2c",
"1e153c6e",
"86e34570",
"eae96fb1",
"860e5e0a",
"5a3e2ab3",
"771fe71c",
"4e3d06fa",
"2965dcb9",
"99e71d0f",
"803e89d6",
"5266c825",
"2e4cc978",
"9c10b36a",
"c6150eba",
"94e2ea78",
"a5fc3c53",
"1e0a2df4",
"f2f74ea7",
"361d2b3d",
"1939260f",
"19c27960",
"5223a708",
"f71312b6",
"ebadfe6e",
"eac31f66",
"e3bc4595",
"a67bc883",
"b17f37d1",
"018cff28",
"c332ddef",
"be6c5aa5",
"65582185",
"68ab9802",
"eecea50f",
"db2f953b",
"2aef7dad",
"5b6e2f84",
"1521b628",
"29076170",
"ecdd4775",
"619f1510",
"13cca830",
"eb61bd96",
"0334fe1e",
"aa0363cf",
"b5735c90",
"4c70a239",
"d59e9e0b",
"cbaade14",
"eecc86bc",
"60622ca7",
"9cab5cab",
"b2f3846e",
"648b1eaf",
"19bdf0ca",
"a02369b9",
"655abb50",
"40685a32",
"3c2ab4b3",
"319ee9d5",
"c021b8f7",
"9b540b19",
"875fa099",
"95f7997e",
"623d7da8",
"f837889a",
"97e32d77",
"11ed935f",
"16681281",
"0e358829",
"c7e61fd6",
"96dedfa1",
"7858ba99",
"57f584a5",
"1b227263",
"9b83c3ff",
"1ac24696",
"cdb30aeb",
"532e3054",
"8fd948e4",
"6dbc3128",
"58ebf2ef",
"34c6ffea",
"fe28ed61",
"ee7c3c73",
"5d4a14d9",
"e864b7e3",
"42105d14",
"203e13e0",
"45eee2b6",
"a3aaabea",
"db6c4f15",
"facb4fd0",
"c742f442",
"ef6abbb5",
"654f3b1d",
"41cd2105",
"d81e799e",
"86854dc7",
"e44b476a",
"3d816250",
"cf62a1f2",
"5b8d2646",
"fc8883a0",
"c1c7b6a3",
"7f1524c3",
"69cb7492",
"47848a0b",
"5692b285",
"095bbf00",
"ad19489d",
"1462b174",
"23820e00",
"58428d2a",
"0c55f5ea",
"1dadf43e",
"233f7061",
"3372f092",
"8d937e41",
"d65fecf1",
"6c223bdb",
"7cde3759",
"cbee7460",
"4085f2a7",
"ce77326e",
"a6078084",
"19f8509e",
"e8efd855",
"61d99735",
"a969a7aa",
"c50c06c2",
"5a04abfc",
"800bcadc",
"9e447a2e",
"c3453484",
"fdd56705",
"0e1e9ec9",
"db73dbd3",
"105588cd",
"675fda79",
"e3674340",
"c5c43465",
"713e38d8",
"3d28f89e",
"f16dff20",
"153e21e7",
"8fb03d4a",
"e6e39f2b",
"db83adf7",
},
{
"e93d5a68",
"948140f7",
"f64c261c",
"94692934",
"411520f7",
"7602d4f7",
"bcf46b2e",
"d4a20068",
"d4082471",
"3320f46a",
"43b7d4b7",
"500061af",
"1e39f62e",
"97244546",
"14214f74",
"bf8b8840",
"4d95fc1d",
"96b591af",
"70f4ddd3",
"66a02f45",
"bfbc09ec",
"03bd9785",
"7fac6dd0",
"31cb8504",
"96eb27b3",
"55fd3941",
"da2547e6",
"abca0a9a",
"28507825",
"530429f4",
"0a2c86da",
"e9b66dfb",
"68dc1462",
"d7486900",
"680ec0a4",
"27a18dee",
"4f3ffea2",
"e887ad8c",
"b58ce006",
"7af4d6b6",
"aace1e7c",
"d3375fec",
"ce78a399",
"406b2a42",
"20fe9e35",
"d9f385b9",
"ee39d7ab",
"3b124e8b",
"1dc9faf7",
"4b6d1856",
"26a36631",
"eae397b2",
"3a6efa74",
"dd5b4332",
"6841e7f7",
"ca7820fb",
"fb0af54e",
"d8feb397",
"454056ac",
"ba489527",
"55533a3a",
"20838d87",
"fe6ba9b7",
"d096954b",
"55a867bc",
"a1159a58",
"cca92963",
"99e1db33",
"a62a4a56",
"3f3125f9",
"5ef47e1c",
"9029317c",
"fdf8e802",
"04272f70",
"80bb155c",
"05282ce3",
"95c11548",
"e4c66d22",
"48c1133f",
"c70f86dc",
"07f9c9ee",
"41041f0f",
"404779a4",
"5d886e17",
"325f51eb",
"d59bc0d1",
"f2bcc18f",
"41113564",
"257b7834",
"602a9c60",
"dff8e8a3",
"1f636c1b",
"0e12b4c2",
"02e1329e",
"af664fd1",
"cad18115",
"6b2395e0",
"333e92e1",
"3b240b62",
"eebeb922",
"85b2a20e",
"e6ba0d99",
"de720c8c",
"2da2f728",
"d0127845",
"95b794fd",
"647d0862",
"e7ccf5f0",
"5449a36f",
"877d48fa",
"c39dfd27",
"f33e8d1e",
"0a476341",
"992eff74",
"3a6f6eab",
"f4f8fd37",
"a812dc60",
"a1ebddf8",
"991be14c",
"db6e6b0d",
"c67b5510",
"6d672c37",
"2765d43b",
"dcd0e804",
"f1290dc7",
"cc00ffa3",
"b5390f92",
"690fed0b",
"667b9ffb",
"cedb7d9c",
"a091cf0b",
"d9155ea3",
"bb132f88",
"515bad24",
"7b9479bf",
"763bd6eb",
"37392eb3",
"cc115979",
"8026e297",
"f42e312d",
"6842ada7",
"c66a2b3b",
"12754ccc",
"782ef11c",
"6a124237",
"b79251e7",
"06a1bbe6",
"4bfb6350",
"1a6b1018",
"11caedfa",
"3d25bdd8",
"e2e1c3c9",
"44421659",
"0a121386",
"d90cec6e",
"d5abea2a",
"64af674e",
"da86a85f",
"bebfe988",
"64e4c3fe",
"9dbc8057",
"f0f7c086",
"60787bf8",
"6003604d",
"d1fd8346",
"f6381fb0",
"7745ae04",
"d736fccc",
"83426b33",
"f01eab71",
"b0804187",
"3c005e5f",
"77a057be",
"bde8ae24",
"55464299",
"bf582e61",
"4e58f48f",
"f2ddfda2",
"f474ef38",
"8789bdc2",
"5366f9c3",
"c8b38e74",
"b475f255",
"46fcd9b9",
"7aeb2661",
"8b1ddf84",
"846a0e79",
"915f95e2",
"466e598e",
"20b45770",
"8cd55591",
"c902de4c",
"b90bace1",
"bb8205d0",
"11a86248",
"7574a99e",
"b77f19b6",
"e0a9dc09",
"662d09a1",
"c4324633",
"e85a1f02",
"09f0be8c",
"4a99a025",
"1d6efe10",
"1ab93d1d",
"0ba5a4df",
"a186f20f",
"2868f169",
"dcb7da83",
"573906fe",
"a1e2ce9b",
"4fcd7f52",
"50115e01",
"a70683fa",
"a002b5c4",
"0de6d027",
"9af88c27",
"773f8641",
"c3604c06",
"61a806b5",
"f0177a28",
"c0f586e0",
"006058aa",
"30dc7d62",
"11e69ed7",
"2338ea63",
"53c2dd94",
"c2c21634",
"bbcbee56",
"90bcb6de",
"ebfc7da1",
"ce591d76",
"6f05e409",
"4b7c0188",
"39720a3d",
"7c927c24",
"86e3725f",
"724d9db9",
"1ac15bb4",
"d39eb8fc",
"ed545578",
"08fca5b5",
"d83d7cd3",
"4dad0fc4",
"1e50ef5e",
"b161e6f8",
"a28514d9",
"6c51133c",
"6fd5c7e7",
"56e14ec4",
"362abfce",
"ddc6c837",
"d79a3234",
"92638212",
"670efa8e",
"406000e0",
},
{
"3a39ce37",
"d3faf5cf",
"abc27737",
"5ac52d1b",
"5cb0679e",
"4fa33742",
"d3822740",
"99bc9bbe",
"d5118e9d",
"bf0f7315",
"d62d1c7e",
"c700c47b",
"b78c1b6b",
"21a19045",
"b26eb1be",
"6a366eb4",
"5748ab2f",
"bc946e79",
"c6a376d2",
"6549c2c8",
"530ff8ee",
"468dde7d",
"d5730a1d",
"4cd04dc6",
"2939bbdb",
"a9ba4650",
"ac9526e8",
"be5ee304",
"a1fad5f0",
"6a2d519a",
"63ef8ce2",
"9a86ee22",
"c089c2b8",
"43242ef6",
"a51e03aa",
"9cf2d0a4",
"83c061ba",
"9be96a4d",
"8fe51550",
"ba645bd6",
"2826a2f9",
"a73a3ae1",
"4ba99586",
"ef5562e9",
"c72fefd3",
"f752f7da",
"3f046f69",
"77fa0a59",
"80e4a915",
"87b08601",
"9b09e6ad",
"3b3ee593",
"e990fd5a",
"9e34d797",
"2cf0b7d9",
"022b8b51",
"96d5ac3a",
"017da67d",
"d1cf3ed6",
"7c7d2d28",
"1f9f25cf",
"adf2b89b",
"5ad6b472",
"5a88f54c",
"e029ac71",
"e019a5e6",
"47b0acfd",
"ed93fa9b",
"e8d3c48d",
"283b57cc",
"f8d56629",
"79132e28",
"785f0191",
"ed756055",
"f7960e44",
"e3d35e8c",
"15056dd4",
"88f46dba",
"03a16125",
"0564f0bd",
"c3eb9e15",
"3c9057a2",
"97271aec",
"a93a072a",
"1b3f6d9b",
"1e6321f5",
"f59c66fb",
"26dcf319",
"7533d928",
"b155fdf5",
"03563482",
"8aba3cbb",
"28517711",
"c20ad9f8",
"abcc5167",
"ccad925f",
"4de81751",
"3830dc8e",
"379d5862",
"9320f991",
"ea7a90c2",
"fb3e7bce",
"5121ce64",
"774fbe32",
"a8b6e37e",
"c3293d46",
"48de5369",
"6413e680",
"a2ae0810",
"dd6db224",
"69852dfd",
"09072166",
"b39a460a",
"6445c0dd",
"586cdecf",
"1c20c8ae",
"5bbef7dd",
"1b588d40",
"ccd2017f",
"6bb4e3bb",
"dda26a7e",
"3a59ff45",
"3e350a44",
"bcb4cdd5",
"72eacea8",
"fa6484bb",
"8d6612ae",
"bf3c6f47",
"d29be463",
"542f5d9e",
"aec2771b",
"f64e6370",
"740e0d8d",
"e75b1357",
"f8721671",
"af537d5d",
"4040cb08",
"4eb4e2cc",
"34d2466a",
"0115af84",
"e1b00428",
"95983a1d",
"06b89fb4",
"ce6ea048",
"6f3f3b82",
"3520ab82",
"011a1d4b",
"277227f8",
"611560b1",
"e7933fdc",
"bb3a792b",
"344525bd",
"a08839e1",
"51ce794b",
"2f32c9b7",
"a01fbac9",
"e01cc87e",
"bcc7d1f6",
"cf0111c3",
"a1e8aac7",
"1a908749",
"d44fbd9a",
"d0dadecb",
"d50ada38",
"0339c32a",
"c6913667",
"8df9317c",
"e0b12b4f",
"f79e59b7",
"43f5bb3a",
"f2d519ff",
"27d9459c",
"bf97222c",
"15e6fc2a",
"0f91fc71",
"9b941525",
"fae59361",
"ceb69ceb",
"c2a86459",
"12baa8d1",
"b6c1075e",
"e3056a0c",
"10d25065",
"cb03a442",
"e0ec6e0e",
"1698db3b",
"4c98a0be",
"3278e964",
"9f1f9532",
"e0d392df",
"d3a0342b",
"8971f21e",
"1b0a7441",
"4ba3348c",
"c5be7120",
"c37632d8",
"df359f8d",
"9b992f2e",
"e60b6f47",
"0fe3f11d",
"e54cda54",
"1edad891",
"ce6279cf",
"cd3e7e6f",
"1618b166",
"fd2c1d05",
"848fd2c5",
"f6fb2299",
"f523f357",
"a6327623",
"93a83531",
"56cccd02",
"acf08162",
"5a75ebb5",
"6e163697",
"88d273cc",
"de966292",
"81b949d0",
"4c50901b",
"71c65614",
"e6c6c7bd",
"327a140a",
"45e1d006",
"c3f27b9a",
"c9aa53fd",
"62a80f00",
"bb25bfe2",
"35bdd2f6",
"71126905",
"b2040222",
"b6cbcf7c",
"cd769c2b",
"53113ec0",
"1640e3d3",
"38abbd60",
"2547adf0",
"ba38209c",
"f746ce76",
"77afa1c5",
"20756060",
"85cbfe4e",
"8ae88dd8",
"7aaaf9b0",
"4cf9aa7e",
"1948c25c",
"02fb8a8c",
"01c36ae4",
"d6ebe1f9",
"90d4f869",
"a65cdea0",
"3f09252d",
"c208e69f",
"b74e6132",
"ce77e25b",
"578fdfe3",
"3ac372e6",
},
};
// Initializing subkeys with digits of pi
String[] P = {
"243f6a88",
"85a308d3",
"13198a2e",
"03707344",
"a4093822",
"299f31d0",
"082efa98",
"ec4e6c89",
"452821e6",
"38d01377",
"be5466cf",
"34e90c6c",
"c0ac29b7",
"c97c50dd",
"3f84d5b5",
"b5470917",
"9216d5d9",
"8979fb1b",
};
// Initializing modVal to 2^32
long modVal = 4294967296L;
/**
* This method returns binary representation of the hexadecimal number passed as parameter
*
* @param hex Number for which binary representation is required
* @return String object which is a binary representation of the hex number passed as parameter
*/
private String hexToBin(String hex) {
String binary = "";
long num;
String binary4B;
int n = hex.length();
for (int i = 0; i < n; i++) {
num = Long.parseUnsignedLong(hex.charAt(i) + "", 16);
binary4B = Long.toBinaryString(num);
binary4B = "0000" + binary4B;
binary4B = binary4B.substring(binary4B.length() - 4);
binary += binary4B;
}
return binary;
}
/**
* This method returns hexadecimal representation of the binary number passed as parameter
*
* @param binary Number for which hexadecimal representation is required
* @return String object which is a hexadecimal representation of the binary number passed as
* parameter
*/
private String binToHex(String binary) {
long num = Long.parseUnsignedLong(binary, 2);
String hex = Long.toHexString(num);
while (hex.length() < (binary.length() / 4)) hex = "0" + hex;
return hex;
}
/**
* This method returns a string obtained by XOR-ing two strings of same length passed a method
* parameters
*
* @param String a and b are string objects which will be XORed and are to be of same length
* @return String object obtained by XOR operation on String a and String b
* */
private String xor(String a, String b) {
a = hexToBin(a);
b = hexToBin(b);
String ans = "";
for (int i = 0; i < a.length(); i++) ans += (char) (((a.charAt(i) - '0') ^ (b.charAt(i) - '0')) + '0');
ans = binToHex(ans);
return ans;
}
/**
* This method returns addition of two hexadecimal numbers passed as parameters and moded with
* 2^32
*
* @param String a and b are hexadecimal numbers
* @return String object which is a is addition that is then moded with 2^32 of hex numbers
* passed as parameters
*/
private String addBin(String a, String b) {
String ans = "";
long n1 = Long.parseUnsignedLong(a, 16);
long n2 = Long.parseUnsignedLong(b, 16);
n1 = (n1 + n2) % modVal;
ans = Long.toHexString(n1);
ans = "00000000" + ans;
return ans.substring(ans.length() - 8);
}
/*F-function splits the 32-bit input into four 8-bit quarters
and uses the quarters as input to the S-boxes.
The S-boxes accept 8-bit input and produce 32-bit output.
The outputs are added modulo 232 and XORed to produce the final 32-bit output
*/
private String f(String plainText) {
String[] a = new String[4];
String ans = "";
for (int i = 0; i < 8; i += 2) {
// column number for S-box is a 8-bit value
long col = Long.parseUnsignedLong(hexToBin(plainText.substring(i, i + 2)), 2);
a[i / 2] = S[i / 2][(int) col];
}
ans = addBin(a[0], a[1]);
ans = xor(ans, a[2]);
ans = addBin(ans, a[3]);
return ans;
}
// generate subkeys
private void keyGenerate(String key) {
int j = 0;
for (int i = 0; i < P.length; i++) {
// XOR-ing 32-bit parts of the key with initial subkeys
P[i] = xor(P[i], key.substring(j, j + 8));
j = (j + 8) % key.length();
}
}
// round function
private String round(int time, String plainText) {
String left, right;
left = plainText.substring(0, 8);
right = plainText.substring(8, 16);
left = xor(left, P[time]);
// output from F function
String fOut = f(left);
right = xor(fOut, right);
// swap left and right
return right + left;
}
/**
* This method returns cipher text for the plaintext passed as the first parameter generated
* using the key passed as the second parameter
*
* @param String plainText is the text which is to be encrypted
* @param String key is the key which is to be used for generating cipher text
* @return String cipherText is the encrypted value
*/
String encrypt(String plainText, String key) {
// generating key
keyGenerate(key);
for (int i = 0; i < 16; i++) plainText = round(i, plainText);
// postprocessing
String right = plainText.substring(0, 8);
String left = plainText.substring(8, 16);
right = xor(right, P[16]);
left = xor(left, P[17]);
return left + right;
}
/**
* This method returns plaintext for the ciphertext passed as the first parameter decoded
* using the key passed as the second parameter
*
* @param String ciphertext is the text which is to be decrypted
* @param String key is the key which is to be used for generating cipher text
* @return String plainText is the decrypted text
*/
String decrypt(String cipherText, String key) {
// generating key
keyGenerate(key);
for (int i = 17; i > 1; i--) cipherText = round(i, cipherText);
// postprocessing
String right = cipherText.substring(0, 8);
String left = cipherText.substring(8, 16);
right = xor(right, P[1]);
left = xor(left, P[0]);
return left + right;
}
}
