xsheetjs/bits/44_offcrypto.js

function _JS2ANSI(str/*:string*/)/*:Array<number>*/ {
	if(typeof cptable !== 'undefined') return cptable.utils.encode(1252, str);
	var o = [], oo = str.split("");
	for(var i = 0; i < oo.length; ++i) o[i] = oo[i].charCodeAt(0);
	return o;
}

/* [MS-OFFCRYPTO] 2.1.4 Version */
function parse_CRYPTOVersion(blob, length/*:?number*/) {
	var o/*:any*/ = {};
	o.Major = blob.read_shift(2);
	o.Minor = blob.read_shift(2);
	/*:: if(length == null) return o; */
	if(length >= 4) blob.l += length - 4;
	return o;
}

/* [MS-OFFCRYPTO] 2.1.5 DataSpaceVersionInfo */
function parse_DataSpaceVersionInfo(blob, length) {
	var o = {};
	o.id = blob.read_shift(0, 'lpp4');
	o.R = parse_CRYPTOVersion(blob, 4);
	o.U = parse_CRYPTOVersion(blob, 4);
	o.W = parse_CRYPTOVersion(blob, 4);
	return o;
}

/* [MS-OFFCRYPTO] 2.1.6.1 DataSpaceMapEntry Structure */
function parse_DataSpaceMapEntry(blob) {
	var len = blob.read_shift(4);
	var end = blob.l + len - 4;
	var o = {};
	var cnt = blob.read_shift(4);
	var comps = [];
	while(cnt-- > 0) {
		/* [MS-OFFCRYPTO] 2.1.6.2 DataSpaceReferenceComponent Structure */
		var rc = {};
		rc.t = blob.read_shift(4);
		rc.v = blob.read_shift(0, 'lpp4');
		comps.push(rc);
	}
	o.name = blob.read_shift(0, 'lpp4');
	o.comps = comps;
	return o;
}

/* [MS-OFFCRYPTO] 2.1.6 DataSpaceMap */
function parse_DataSpaceMap(blob, length) {
	var o = [];
	blob.l += 4; // must be 0x8
	var cnt = blob.read_shift(4);
	while(cnt-- > 0) o.push(parse_DataSpaceMapEntry(blob));
	return o;
}

/* [MS-OFFCRYPTO] 2.1.7 DataSpaceDefinition */
function parse_DataSpaceDefinition(blob, length) {
	var o = [];
	blob.l += 4; // must be 0x8
	var cnt = blob.read_shift(4);
	while(cnt-- > 0) o.push(blob.read_shift(0, 'lpp4'));
	return o;
}

/* [MS-OFFCRYPTO] 2.1.8 DataSpaceDefinition */
function parse_TransformInfoHeader(blob, length) {
	var o = {};
	var len = blob.read_shift(4);
	var tgt = blob.l + len - 4;
	blob.l += 4; // must be 0x1
	o.id = blob.read_shift(0, 'lpp4');
	// tgt == len
	o.name = blob.read_shift(0, 'lpp4');
	o.R = parse_CRYPTOVersion(blob, 4);
	o.U = parse_CRYPTOVersion(blob, 4);
	o.W = parse_CRYPTOVersion(blob, 4);
	return o;
}

function parse_Primary(blob, length) {
	/* [MS-OFFCRYPTO] 2.2.6 IRMDSTransformInfo */
	var hdr = parse_TransformInfoHeader(blob);
	/* [MS-OFFCRYPTO] 2.1.9 EncryptionTransformInfo */
	hdr.ename = blob.read_shift(0, '8lpp4');
	hdr.blksz = blob.read_shift(4);
	hdr.cmode = blob.read_shift(4);
	if(blob.read_shift(4) != 0x04) throw new Error("Bad !Primary record");
	return hdr;
}

/* [MS-OFFCRYPTO] 2.3.2 Encryption Header */
function parse_EncryptionHeader(blob, length/*:number*/) {
	var tgt = blob.l + length;
	var o = {};
	o.Flags = (blob.read_shift(4) & 0x3F);
	blob.l += 4;
	o.AlgID = blob.read_shift(4);
	var valid = false;
	switch(o.AlgID) {
		case 0x660E: case 0x660F: case 0x6610: valid = (o.Flags == 0x24); break;
		case 0x6801: valid = (o.Flags == 0x04); break;
		case 0: valid = (o.Flags == 0x10 || o.Flags == 0x04 || o.Flags == 0x24); break;
		default: throw 'Unrecognized encryption algorithm: ' + o.AlgID;
	}
	if(!valid) throw new Error("Encryption Flags/AlgID mismatch");
	o.AlgIDHash = blob.read_shift(4);
	o.KeySize = blob.read_shift(4);
	o.ProviderType = blob.read_shift(4);
	blob.l += 8;
	o.CSPName = blob.read_shift((tgt-blob.l)>>1, 'utf16le').slice(0,-1);
	blob.l = tgt;
	return o;
}

/* [MS-OFFCRYPTO] 2.3.3 Encryption Verifier */
function parse_EncryptionVerifier(blob, length/*:number*/) {
	var o = {};
	blob.l += 4; // SaltSize must be 0x10
	o.Salt = blob.slice(blob.l, blob.l+16); blob.l += 16;
	o.Verifier = blob.slice(blob.l, blob.l+16); blob.l += 16;
	var sz = blob.read_shift(4);
	o.VerifierHash = blob.slice(blob.l, blob.l + sz); blob.l += sz;
	return o;
}

/* [MS-OFFCRYPTO] 2.3.4.* EncryptionInfo Stream */
function parse_EncryptionInfo(blob, length/*:?number*/) {
	var vers = parse_CRYPTOVersion(blob);
	switch(vers.Minor) {
		case 0x02: return parse_EncInfoStd(blob, vers);
		case 0x03: return parse_EncInfoExt(blob, vers);
		case 0x04: return parse_EncInfoAgl(blob, vers);
	}
	throw new Error("ECMA-376 Encrypted file unrecognized Version: " + vers.Minor);
}

/* [MS-OFFCRYPTO] 2.3.4.5  EncryptionInfo Stream (Standard Encryption) */
function parse_EncInfoStd(blob, vers) {
	var flags = blob.read_shift(4);
	if((flags & 0x3F) != 0x24) throw new Error("EncryptionInfo mismatch");
	var sz = blob.read_shift(4);
	var tgt = blob.l + sz;
	var hdr = parse_EncryptionHeader(blob, sz);
	var verifier = parse_EncryptionVerifier(blob, blob.length - blob.l);
	return { t:"Std", h:hdr, v:verifier };
}
/* [MS-OFFCRYPTO] 2.3.4.6  EncryptionInfo Stream (Extensible Encryption) */
function parse_EncInfoExt(blob, vers) { throw new Error("File is password-protected: ECMA-376 Extensible"); }
/* [MS-OFFCRYPTO] 2.3.4.10 EncryptionInfo Stream (Agile Encryption) */
function parse_EncInfoAgl(blob, vers) { throw new Error("File is password-protected: ECMA-376 Agile"); }




/* [MS-OFFCRYPTO] 2.3.5.1 RC4 CryptoAPI Encryption Header */
function parse_RC4CryptoHeader(blob, length/*:number*/) {
	var o = {};
	var vers = o.EncryptionVersionInfo = parse_CRYPTOVersion(blob, 4); length -= 4;
	if(vers.Minor != 2) throw new Error('unrecognized minor version code: ' + vers.Minor);
	if(vers.Major > 4 || vers.Major < 2) throw new Error('unrecognized major version code: ' + vers.Major);
	o.Flags = blob.read_shift(4); length -= 4;
	var sz = blob.read_shift(4); length -= 4;
	o.EncryptionHeader = parse_EncryptionHeader(blob, sz); length -= sz;
	o.EncryptionVerifier = parse_EncryptionVerifier(blob, length);
	return o;
}
/* [MS-OFFCRYPTO] 2.3.6.1 RC4 Encryption Header */
function parse_RC4Header(blob, length/*:number*/) {
	var o = {};
	var vers = o.EncryptionVersionInfo = parse_CRYPTOVersion(blob, 4); length -= 4;
	if(vers.Major != 1 || vers.Minor != 1) throw 'unrecognized version code ' + vers.Major + ' : ' + vers.Minor;
	o.Salt = blob.read_shift(16);
	o.EncryptedVerifier = blob.read_shift(16);
	o.EncryptedVerifierHash = blob.read_shift(16);
	return o;
}

/* [MS-OFFCRYPTO] 2.3.7.1 Binary Document Password Verifier Derivation */
function crypto_CreatePasswordVerifier_Method1(Password/*:string*/) {
	var Verifier = 0x0000, PasswordArray;
	var PasswordDecoded = _JS2ANSI(Password);
	var len = PasswordDecoded.length + 1, i, PasswordByte;
	var Intermediate1, Intermediate2, Intermediate3;
	PasswordArray = new_raw_buf(len);
	PasswordArray[0] = PasswordDecoded.length;
	for(i = 1; i != len; ++i) PasswordArray[i] = PasswordDecoded[i-1];
	for(i = len-1; i >= 0; --i) {
		PasswordByte = PasswordArray[i];
		Intermediate1 = ((Verifier & 0x4000) === 0x0000) ? 0 : 1;
		Intermediate2 = (Verifier << 1) & 0x7FFF;
		Intermediate3 = Intermediate1 | Intermediate2;
		Verifier = Intermediate3 ^ PasswordByte;
	}
	return Verifier ^ 0xCE4B;
}

/* [MS-OFFCRYPTO] 2.3.7.2 Binary Document XOR Array Initialization */
var crypto_CreateXorArray_Method1 = (function() {
	var PadArray = [0xBB, 0xFF, 0xFF, 0xBA, 0xFF, 0xFF, 0xB9, 0x80, 0x00, 0xBE, 0x0F, 0x00, 0xBF, 0x0F, 0x00];
	var InitialCode = [0xE1F0, 0x1D0F, 0xCC9C, 0x84C0, 0x110C, 0x0E10, 0xF1CE, 0x313E, 0x1872, 0xE139, 0xD40F, 0x84F9, 0x280C, 0xA96A, 0x4EC3];
	var XorMatrix = [0xAEFC, 0x4DD9, 0x9BB2, 0x2745, 0x4E8A, 0x9D14, 0x2A09, 0x7B61, 0xF6C2, 0xFDA5, 0xEB6B, 0xC6F7, 0x9DCF, 0x2BBF, 0x4563, 0x8AC6, 0x05AD, 0x0B5A, 0x16B4, 0x2D68, 0x5AD0, 0x0375, 0x06EA, 0x0DD4, 0x1BA8, 0x3750, 0x6EA0, 0xDD40, 0xD849, 0xA0B3, 0x5147, 0xA28E, 0x553D, 0xAA7A, 0x44D5, 0x6F45, 0xDE8A, 0xAD35, 0x4A4B, 0x9496, 0x390D, 0x721A, 0xEB23, 0xC667, 0x9CEF, 0x29FF, 0x53FE, 0xA7FC, 0x5FD9, 0x47D3, 0x8FA6, 0x0F6D, 0x1EDA, 0x3DB4, 0x7B68, 0xF6D0, 0xB861, 0x60E3, 0xC1C6, 0x93AD, 0x377B, 0x6EF6, 0xDDEC, 0x45A0, 0x8B40, 0x06A1, 0x0D42, 0x1A84, 0x3508, 0x6A10, 0xAA51, 0x4483, 0x8906, 0x022D, 0x045A, 0x08B4, 0x1168, 0x76B4, 0xED68, 0xCAF1, 0x85C3, 0x1BA7, 0x374E, 0x6E9C, 0x3730, 0x6E60, 0xDCC0, 0xA9A1, 0x4363, 0x86C6, 0x1DAD, 0x3331, 0x6662, 0xCCC4, 0x89A9, 0x0373, 0x06E6, 0x0DCC, 0x1021, 0x2042, 0x4084, 0x8108, 0x1231, 0x2462, 0x48C4];
	var Ror = function(Byte) { return ((Byte/2) | (Byte*128)) & 0xFF; };
	var XorRor = function(byte1, byte2) { return Ror(byte1 ^ byte2); };
	var CreateXorKey_Method1 = function(Password) {
		var XorKey = InitialCode[Password.length - 1];
		var CurrentElement = 0x68;
		for(var i = Password.length-1; i >= 0; --i) {
			var Char = Password[i];
			for(var j = 0; j != 7; ++j) {
				if(Char & 0x40) XorKey ^= XorMatrix[CurrentElement];
				Char *= 2; --CurrentElement;
			}
		}
		return XorKey;
	};
	return function(password/*:string*/) {
		var Password = _JS2ANSI(password);
		var XorKey = CreateXorKey_Method1(Password);
		var Index = Password.length;
		var ObfuscationArray = new_raw_buf(16);
		for(var i = 0; i != 16; ++i) ObfuscationArray[i] = 0x00;
		var Temp, PasswordLastChar, PadIndex;
		if((Index & 1) === 1) {
			Temp = XorKey >> 8;
			ObfuscationArray[Index] = XorRor(PadArray[0], Temp);
			--Index;
			Temp = XorKey & 0xFF;
			PasswordLastChar = Password[Password.length - 1];
			ObfuscationArray[Index] = XorRor(PasswordLastChar, Temp);
		}
		while(Index > 0) {
			--Index;
			Temp = XorKey >> 8;
			ObfuscationArray[Index] = XorRor(Password[Index], Temp);
			--Index;
			Temp = XorKey & 0xFF;
			ObfuscationArray[Index] = XorRor(Password[Index], Temp);
		}
		Index = 15;
		PadIndex = 15 - Password.length;
		while(PadIndex > 0) {
			Temp = XorKey >> 8;
			ObfuscationArray[Index] = XorRor(PadArray[PadIndex], Temp);
			--Index;
			--PadIndex;
			Temp = XorKey & 0xFF;
			ObfuscationArray[Index] = XorRor(Password[Index], Temp);
			--Index;
			--PadIndex;
		}
		return ObfuscationArray;
	};
})();

/* [MS-OFFCRYPTO] 2.3.7.3 Binary Document XOR Data Transformation Method 1 */
var crypto_DecryptData_Method1 = function(password/*:string*/, Data, XorArrayIndex, XorArray, O) {
	/* If XorArray is set, use it; if O is not set, make changes in-place */
	if(!O) O = Data;
	if(!XorArray) XorArray = crypto_CreateXorArray_Method1(password);
	var Index, Value;
	for(Index = 0; Index != Data.length; ++Index) {
		Value = Data[Index];
		Value ^= XorArray[XorArrayIndex];
		Value = ((Value>>5) | (Value<<3)) & 0xFF;
		O[Index] = Value;
		++XorArrayIndex;
	}
	return [O, XorArrayIndex, XorArray];
};

var crypto_MakeXorDecryptor = function(password/*:string*/) {
	var XorArrayIndex = 0, XorArray = crypto_CreateXorArray_Method1(password);
	return function(Data) {
		var O = crypto_DecryptData_Method1("", Data, XorArrayIndex, XorArray);
		XorArrayIndex = O[1];
		return O[0];
	};
};

/* 2.5.343 */
function parse_XORObfuscation(blob, length, opts, out) {
	var o = ({ key: parseuint16(blob), verificationBytes: parseuint16(blob) }/*:any*/);
	if(opts.password) o.verifier = crypto_CreatePasswordVerifier_Method1(opts.password);
	out.valid = o.verificationBytes === o.verifier;
	if(out.valid) out.insitu_decrypt = crypto_MakeXorDecryptor(opts.password);
	return o;
}

/* 2.4.117 */
function parse_FilePassHeader(blob, length/*:number*/, oo) {
	var o = oo || {}; o.Info = blob.read_shift(2); blob.l -= 2;
	if(o.Info === 1) o.Data = parse_RC4Header(blob, length);
	else o.Data = parse_RC4CryptoHeader(blob, length);
	return o;
}
function parse_FilePass(blob, length/*:number*/, opts) {
	var o = ({ Type: opts.biff >= 8 ? blob.read_shift(2) : 0 }/*:any*/); /* wEncryptionType */
	if(o.Type) parse_FilePassHeader(blob, length-2, o);
	else parse_XORObfuscation(blob, length-2, opts, o);
	return o;
}