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https://issues.apache.org/jira/browse/CRYPTO-60?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15299404#comment-15299404
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Xianda Ke edited comment on CRYPTO-60 at 10/14/16 8:29 AM:
---
Here is a sample. The behavior is similar to JCE.
{code:title=GCMSample.java|borderStyle=solid}
final String transform = "AES/GCM/NoPadding";
Random r = new Random();
int textLength = r.nextInt(1024*1024);
int ivLength = r.nextInt(60);
int keyLength = 16;
int tagLength = 128; // bits
int aadLength = r.nextInt(128);
byte[] keyBytes = new byte[keyLength];
byte[] plainBytes = new byte[textLength];
byte[] ivBytes = new byte[ivLength];
byte[] aadBytes = new byte[aadLength];
r.nextBytes(keyBytes);
r.nextBytes(plainBytes);
r.nextBytes(ivBytes);
r.nextBytes(aadBytes);
byte[] encOutput = new byte[plainBytes.length + (tagLength >> 3)];
byte[] decOutput = new byte[plainBytes.length];
try {
CryptoCipher c = Utils.getCipherInstance(transformation);
Key key = new SecretKeySpec(keyBytes, "AES");
GCMParameterSpec iv = new GCMParameterSpec(tagLength, ivBytes);
c.init(CryptoCipher.ENCRYPT_MODE, key, iv);
c.updateAAD(aadBytes);
c.doFinal(plainBytes, 0, plainBytes.length, encOutput, 0);
c.close();
}
catch (Exception ex) {
System.out.println(ex.getMessage());
}
// Tamper the encrypted data.
encOutput[0] = (byte)(encOutput[0] + 1);
try {
CryptoCipher c = Utils.getCipherInstance(transformation, props);
Key key = new SecretKeySpec(keyBytes, "AES");
GCMParameterSpec iv = new GCMParameterSpec(tagLength, ivBytes);
c.init(CryptoCipher.DECRYPT_MODE, key, iv);
c.updateAAD(aadBytes);
c.doFinal(encOutput, 0, encOutput.length, decOutput, 0);
c.close();
}
catch (AEADBadTagException ex) {
System.out.println(ex.getMessage()); // "Tag mismatch!"
}
{code}
was (Author: kexianda):
Here is a sample. The behavior is similar to JCE.
{code:title=GCMSample.java|borderStyle=solid}
CipherTransformation transformation =
CipherTransformation.AES_GCM_NOPADDING;
Properties props = new Properties();
props.setProperty(ConfigurationKeys.COMMONS_CRYPTO_CIPHER_CLASSES_KEY,
cipherClass);
Random r = new Random();
int textLength = r.nextInt(1024*1024);
int ivLength = r.nextInt(60);
int keyLength = 16;
int tagLength = 128; // bits
int aadLength = r.nextInt(128);
byte[] keyBytes = new byte[keyLength];
byte[] plainBytes = new byte[textLength];
byte[] ivBytes = new byte[ivLength];
byte[] aadBytes = new byte[aadLength];
r.nextBytes(keyBytes);
r.nextBytes(plainBytes);
r.nextBytes(ivBytes);
r.nextBytes(aadBytes);
byte[] encOutput = new byte[plainBytes.length + (tagLength >> 3)];
byte[] decOutput = new byte[plainBytes.length];
try {
CryptoCipher c = Utils.getCipherInstance(transformation, props);
Key key = new SecretKeySpec(keyBytes, "AES");
GCMParameterSpec iv = new GCMParameterSpec(tagLength, ivBytes);
c.init(CryptoCipher.ENCRYPT_MODE, key, iv);
c.updateAAD(aadBytes);
c.doFinal(plainBytes, 0, plainBytes.length, encOutput, 0);
c.close();
}
catch (Exception ex) {
System.out.println(ex.getMessage());
}
// Tamper the encrypted data.
encOutput[0] = (byte)(encOutput[0] + 1);
try {
CryptoCipher c = Utils.getCipherInstance(transformation, props);
Key key = new SecretKeySpec(keyBytes, "AES");
GCMParameterSpec iv = new GCMParameterSpec(tagLength, ivBytes);
c.init(CryptoCipher.DECRYPT_MODE, key, iv);
c.updateAAD(aadBytes);
c.doFinal(encOutput, 0, encOutput.length, decOutput, 0);
c.close();
}
catch (AEADBadTagException ex) {
System.out.println(ex.getMessage()); // "Tag mismatch!"
}
{code}
> opensslCipher support GCM mode
> ---
>
> Key: CRYPTO-60
> URL: https://issues.apache.org/jira/browse/CRYPTO-60
> Project: Commons Crypto
> Issue Type: Sub-task
>Reporter: Xianda Ke
>Assignee: Xianda Ke
>
> The interface would look like JCE. In encryption mode, the authenticated tag
> information is appended at the end of output.
> In decryption mode, the authenticated tag should appended at the end of
> input. If the encrypted data is tampered, it will throw an
> AEADBadTagException.
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