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https://github.com/Maschell/JNUSLib.git
synced 2024-11-04 23:35:10 +01:00
Optimize the hash checks when decrypting a non hash file
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da196e845f
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@ -60,12 +60,10 @@ public class NUSDecryption extends AESDecryption {
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public void decryptFileStream(InputStream inputStream, OutputStream outputStream, long fileOffset, long filesize, short contentIndex, byte[] h3hash,
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long expectedSizeForHash) throws IOException, CheckSumWrongException {
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MessageDigest sha1 = null;
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MessageDigest sha1fallback = null;
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if (h3hash != null) {
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try {
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sha1 = MessageDigest.getInstance("SHA1");
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sha1fallback = MessageDigest.getInstance("SHA1");
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} catch (NoSuchAlgorithmException e) {
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e.printStackTrace();
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}
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@ -86,9 +84,7 @@ public class NUSDecryption extends AESDecryption {
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int inBlockBuffer;
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long written = 0;
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long writtenFallback = 0;
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int skipoffset = (int) (fileOffset % 0x8000);
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long writtenHash = 0;
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try {
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// The input stream has been prepared to start 16 bytes earlier on this case.
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@ -139,35 +135,30 @@ public class NUSDecryption extends AESDecryption {
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outputStream.write(output, 0, toWrite);
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if (sha1 != null && sha1fallback != null) {
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sha1.update(output, 0, toWrite);
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if (sha1 != null) {
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// In some cases it's using the hash of the whole .app file instead of the part
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// that's been actually used.
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long toFallback = inBlockBuffer;
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if (writtenFallback + toFallback > expectedSizeForHash) {
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toFallback = expectedSizeForHash - writtenFallback;
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if (written + toFallback > expectedSizeForHash) {
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toFallback = expectedSizeForHash - written;
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}
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sha1fallback.update(output, 0, (int) toFallback);
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writtenFallback += toFallback;
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sha1.update(output, 0, (int) toFallback);
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writtenHash += toFallback;
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}
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if (written >= filesize && h3hash == null) {
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break;
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}
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} while (inBlockBuffer == BLOCKSIZE);
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if (sha1 != null && sha1fallback != null) {
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long missingInHash = expectedSizeForHash - writtenFallback;
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if (sha1 != null) {
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long missingInHash = expectedSizeForHash - writtenHash;
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if (missingInHash > 0) {
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sha1fallback.update(new byte[(int) missingInHash]);
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sha1.update(new byte[(int) missingInHash]);
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}
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byte[] calculated_hash1 = sha1.digest();
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byte[] calculated_hash2 = sha1fallback.digest();
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byte[] expected_hash = h3hash;
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if (!Arrays.equals(calculated_hash1, expected_hash) && !Arrays.equals(calculated_hash2, expected_hash)) {
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throw new CheckSumWrongException("hash checksum failed", calculated_hash1, expected_hash);
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if (!Arrays.equals(calculated_hash1, h3hash)) {
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throw new CheckSumWrongException("hash checksum failed", calculated_hash1, h3hash);
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} else {
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log.finest("Hash DOES match saves output stream.");
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}
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