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Computes the lengths in the template dynamically according to the mod length when importing RSA keys

This commit is contained in:
dangfan 2020-12-18 23:06:03 +08:00
parent 258cd4c836
commit ea70f7307e
1 changed files with 25 additions and 6 deletions
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31
OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/SecurityTokenUtils.java
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@ -74,6 +74,18 @@ public class SecurityTokenUtils {
return attrs;
}
private static byte[] generateLengthByteArray(int length) throws IOException {
if (length < 128) {
return new byte[]{(byte) length};
} else if (length < 256) {
return new byte[]{(byte) 0x81, (byte) length};
} else if (length < 65536) {
return new byte[]{(byte) 0x82, (byte) (length >> 8), (byte) (length & 0xFF)};
} else {
throw new IOException("Unsupported key length");
}
}
public static byte[] createRSAPrivKeyTemplate(RSAPrivateCrtKey secretKey, KeyType slot,
RSAKeyFormat format) throws IOException {
ByteArrayOutputStream stream = new ByteArrayOutputStream(),
@ -87,33 +99,40 @@ public class SecurityTokenUtils {
writeBits(data, secretKey.getPublicExponent(), expLengthBytes);
final int modLengthBytes = format.getModulusLength() / 8;
final byte[] lengthByteArray = generateLengthByteArray(modLengthBytes / 2);
// Prime P, length modLengthBytes / 2
template.write(Hex.decode("928180"));
template.write(Hex.decode("92"));
template.write(lengthByteArray);
writeBits(data, secretKey.getPrimeP(), modLengthBytes / 2);
// Prime Q, length modLengthBytes / 2
template.write(Hex.decode("938180"));
template.write(Hex.decode("93"));
template.write(lengthByteArray);
writeBits(data, secretKey.getPrimeQ(), modLengthBytes / 2);
if (format.getAlgorithmFormat().isIncludeCrt()) {
// Coefficient (1/q mod p), length modLengthBytes / 2
template.write(Hex.decode("948180"));
template.write(Hex.decode("94"));
template.write(lengthByteArray);
writeBits(data, secretKey.getCrtCoefficient(), modLengthBytes / 2);
// Prime exponent P (d mod (p - 1)), length modLengthBytes / 2
template.write(Hex.decode("958180"));
template.write(Hex.decode("95"));
template.write(lengthByteArray);
writeBits(data, secretKey.getPrimeExponentP(), modLengthBytes / 2);
// Prime exponent Q (d mod (1 - 1)), length modLengthBytes / 2
template.write(Hex.decode("968180"));
template.write(Hex.decode("96"));
template.write(lengthByteArray);
writeBits(data, secretKey.getPrimeExponentQ(), modLengthBytes / 2);
}
if (format.getAlgorithmFormat().isIncludeModulus()) {
// Modulus, length modLengthBytes, last item in private key template
template.write(Hex.decode("97820100"));
template.write(Hex.decode("97"));
template.write(generateLengthByteArray(modLengthBytes));
writeBits(data, secretKey.getModulus(), modLengthBytes);
}