aboutsummaryrefslogtreecommitdiffstats
path: root/OpenKeychain/src
diff options
context:
space:
mode:
Diffstat (limited to 'OpenKeychain/src')
-rw-r--r--OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java39
1 files changed, 29 insertions, 10 deletions
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java
index b143085d5..c69eeaf04 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java
@@ -25,7 +25,6 @@ import org.spongycastle.bcpg.SymmetricKeyAlgorithmTags;
import org.spongycastle.bcpg.sig.Features;
import org.spongycastle.bcpg.sig.KeyFlags;
import org.spongycastle.jce.spec.ElGamalParameterSpec;
-import org.spongycastle.openpgp.PGPEncryptedData;
import org.spongycastle.openpgp.PGPException;
import org.spongycastle.openpgp.PGPKeyPair;
import org.spongycastle.openpgp.PGPPrivateKey;
@@ -104,6 +103,26 @@ public class PgpKeyOperation {
CompressionAlgorithmTags.ZIP
};
+ /*
+ * Note: s2kcount is a number between 0 and 0xff that controls the
+ * number of times to iterate the password hash before use. More
+ * iterations are useful against offline attacks, as it takes more
+ * time to check each password. The actual number of iterations is
+ * rather complex, and also depends on the hash function in use.
+ * Refer to Section 3.7.1.3 in rfc4880.txt. Bigger numbers give
+ * you more iterations. As a rough rule of thumb, when using
+ * SHA256 as the hashing function, 0x10 gives you about 64
+ * iterations, 0x20 about 128, 0x30 about 256 and so on till 0xf0,
+ * or about 1 million iterations. The maximum you can go to is
+ * 0xff, or about 2 million iterations. I'll use 0xc0 as a
+ * default -- about 130,000 iterations.
+ *
+ * http://kbsriram.com/2013/01/generating-rsa-keys-with-bouncycastle.html
+ */
+ private static final int SECRET_KEY_ENCRYPTOR_HASH_ALGO = HashAlgorithmTags.SHA512;
+ private static final int SECRET_KEY_ENCRYPTOR_SYMMETRIC_ALGO = SymmetricKeyAlgorithmTags.AES_256;
+ private static final int SECRET_KEY_ENCRYPTOR_S2K_COUNT = 0xc0;
+
public PgpKeyOperation(Progressable progress) {
super();
if (progress != null) {
@@ -250,10 +269,10 @@ public class PgpKeyOperation {
progress(R.string.progress_building_master_key, 40);
// Build key encrypter and decrypter based on passphrase
- PGPDigestCalculator sha512Calc = new JcaPGPDigestCalculatorProviderBuilder()
- .build().get(HashAlgorithmTags.SHA512);
+ PGPDigestCalculator encryptorHashCalc = new JcaPGPDigestCalculatorProviderBuilder()
+ .build().get(SECRET_KEY_ENCRYPTOR_HASH_ALGO);
PBESecretKeyEncryptor keyEncryptor = new JcePBESecretKeyEncryptorBuilder(
- PGPEncryptedData.AES_256, sha512Calc)
+ SECRET_KEY_ENCRYPTOR_SYMMETRIC_ALGO, encryptorHashCalc, SECRET_KEY_ENCRYPTOR_S2K_COUNT)
.setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME).build("".toCharArray());
// NOTE: only SHA1 is supported for key checksum calculations.
@@ -705,10 +724,10 @@ public class PgpKeyOperation {
PGPSecretKey sKey; {
// Build key encrypter and decrypter based on passphrase
- PGPDigestCalculator sha512Calc = new JcaPGPDigestCalculatorProviderBuilder()
- .build().get(HashAlgorithmTags.SHA512);
+ PGPDigestCalculator encryptorHashCalc = new JcaPGPDigestCalculatorProviderBuilder()
+ .build().get(SECRET_KEY_ENCRYPTOR_HASH_ALGO);
PBESecretKeyEncryptor keyEncryptor = new JcePBESecretKeyEncryptorBuilder(
- PGPEncryptedData.AES_256, sha512Calc)
+ SECRET_KEY_ENCRYPTOR_SYMMETRIC_ALGO, encryptorHashCalc, SECRET_KEY_ENCRYPTOR_S2K_COUNT)
.setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME).build(passphrase.toCharArray());
// NOTE: only SHA1 is supported for key checksum calculations.
@@ -731,13 +750,13 @@ public class PgpKeyOperation {
log.add(LogLevel.INFO, LogType.MSG_MF_PASSPHRASE, indent);
indent += 1;
- PGPDigestCalculator sha512Calc = new JcaPGPDigestCalculatorProviderBuilder().build()
- .get(HashAlgorithmTags.SHA512);
+ PGPDigestCalculator encryptorHashCalc = new JcaPGPDigestCalculatorProviderBuilder().build()
+ .get(SECRET_KEY_ENCRYPTOR_HASH_ALGO);
PBESecretKeyDecryptor keyDecryptor = new JcePBESecretKeyDecryptorBuilder().setProvider(
Constants.BOUNCY_CASTLE_PROVIDER_NAME).build(passphrase.toCharArray());
// Build key encryptor based on new passphrase
PBESecretKeyEncryptor keyEncryptorNew = new JcePBESecretKeyEncryptorBuilder(
- PGPEncryptedData.AES_256, sha512Calc)
+ SECRET_KEY_ENCRYPTOR_SYMMETRIC_ALGO, encryptorHashCalc, SECRET_KEY_ENCRYPTOR_S2K_COUNT)
.setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME).build(
saveParcel.mNewPassphrase.toCharArray());