diff options
Diffstat (limited to 'OpenKeychain/src')
| -rw-r--r-- | OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java | 39 |
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()); |