如何修复AES密钥长度无效？ [英] How to fix Invalid AES key length?
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问题描述
我正在基于网络的文本加密和解密项目在eclipse上（在Struts 2之后）
I am working on a web based text encryption and decryption project on eclipse(following Struts 2)
每当我输入密码和明文我得到无效的AES密钥长度错误。
Whenever I enter the password and the plain text I get a Invalid AES Key Length error.
服务类（SymAES.java）
package com.anoncrypt.services;
import java.security.Key;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
public class SymAES
{
private static final String ALGORITHM = "AES";
private static byte[] keyValue= new byte[] { 'T', 'h', 'i', 's', 'I', 's', 'A', 'S', 'e', 'c', 'r', 'e', 't', 'K', 'e', 'y' };
public String encode(String valueToEnc) throws Exception {
System.out.println("The Key byte value"+keyValue );
Key key = generateKey();
Cipher c = Cipher.getInstance(ALGORITHM);
c.init(Cipher.ENCRYPT_MODE, key);
byte[] encValue = c.doFinal(valueToEnc.getBytes());
String encryptedValue = new BASE64Encoder().encode(encValue);
return encryptedValue;
}
public String decode(String encryptedValue) throws Exception {
Key key = generateKey();
Cipher c = Cipher.getInstance(ALGORITHM);
c.init(Cipher.DECRYPT_MODE, key);
byte[] decordedValue = new BASE64Decoder().decodeBuffer(encryptedValue);
byte[] decValue = c.doFinal(decordedValue);
String decryptedValue = new String(decValue);
return decryptedValue;
}
private static Key generateKey() throws Exception {
//System.out.println("passs value"+pass);
System.out.println("The Key byte value instde genkey"+keyValue );
Key key = new SecretKeySpec(keyValue, ALGORITHM);
return key;
}
public void start(String passcode)throws Exception
{
keyValue = passcode.getBytes();
System.out.println("passcode"+passcode);
System.out.println("The Key byte value inside start"+keyValue );
}
}
以下是Action类（SymEncrypt.java）
package com.anoncrypt.actions;
import com.anoncrypt.services.SymAES;
public class SymEncrypt {
private String encrypt;
private String encrypted;
private String password;
boolean TEMP;
public String execute() throws Exception {
SymAES ob=new SymAES();
ob.start(getPassword());
setEncrypted( ob.encode(getEncrypt()));
System.out.println("into action class "+getEncrypted());
if(getEncrypted().equals(null))
return "error";
else
return "success";
}
public String getEncrypted() {
return encrypted;
}
public void setEncrypted(String encrypted) {
this.encrypted = encrypted;
}
public String getEncrypt() {
return encrypt;
}
public void setEncrypt(String encrypt) {
this.encrypt = encrypt;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}
这是错误
java.security.InvalidKeyException: Invalid AES key length: 6 bytes
com.sun.crypto.provider.AESCrypt.init(AESCrypt.java:87)
com.sun.crypto.provider.ElectronicCodeBook.init(ElectronicCodeBook.java:93)
com.sun.crypto.provider.CipherCore.init(CipherCore.java:582)
com.sun.crypto.provider.CipherCore.init(CipherCore.java:458)
com.sun.crypto.provider.AESCipher.engineInit(AESCipher.java:307)
javax.crypto.Cipher.implInit(Cipher.java:797)
javax.crypto.Cipher.chooseProvider(Cipher.java:859)
javax.crypto.Cipher.init(Cipher.java:1229)
javax.crypto.Cipher.init(Cipher.java:1166)
com.anoncrypt.services.SymAES.encode(SymAES.java:35)
com.anoncrypt.actions.SymEncrypt.execute(SymEncrypt.java:24)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:870)
ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1293)
ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:68)
com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethodWithDebugInfo(XWorkMethodAccessor.java:117)
com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethod(XWorkMethodAccessor.java:108)
ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1369)
ognl.ASTMethod.getValueBody(ASTMethod.java:90)
ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)
ognl.SimpleNode.getValue(SimpleNode.java:258)
ognl.Ognl.getValue(Ognl.java:494)
ognl.Ognl.getValue(Ognl.java:458)
com.opensymphony.xwork2.ognl.OgnlUtil$2.execute(OgnlUtil.java:309)
com.opensymphony.xwork2.ognl.OgnlUtil.compileAndExecute(OgnlUtil.java:340)
com.opensymphony.xwork2.ognl.OgnlUtil.getValue(OgnlUtil.java:307)
com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:423)
com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:287)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:250)
org.apache.struts2.interceptor.DeprecationInterceptor.intercept(DeprecationInterceptor.java:41)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:167)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265)
org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:76)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
org.apache.struts2.interceptor.DateTextFieldInterceptor.intercept(DateTextFieldInterceptor.java:125)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:253)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:139)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)
org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:564)
org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:81)
org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)
推荐答案
AES只支持16,24或32字节。您需要提供完全相同的金额，或者从您输入的内容中导出密钥。
AES only supports key sizes of 16, 24 or 32 bytes. You either need to provide exactly that amount or you derive the key from what you type in.
从密码短语中导出密钥有不同的方法。 Java为此提供了一个PBKDF2实现。
There are different ways to derive the key from a passphrase. Java provides a PBKDF2 implementation for such a purpose.
我使用了erickson的回答
I used erickson's answer to paint a complete picture (only encryption, since the decryption is similar, but includes splitting the ciphertext):
SecureRandom random = new SecureRandom();
byte[] salt = new byte[16];
random.nextBytes(salt);
KeySpec spec = new PBEKeySpec("password".toCharArray(), salt, 65536, 256); // AES-256
SecretKeyFactory f = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
byte[] key = f.generateSecret(spec).getEncoded();
byte[] ivBytes = new byte[16];
random.nextBytes(ivBytes);
IvParameterSpec iv = new IvParameterSpec(ivBytes);
Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");
c.init(Cipher.ENCRYPT_MODE, key, iv);
byte[] encValue = c.doFinal(valueToEnc.getBytes());
byte[] finalCiphertext = new byte[encValue.length+2*16];
System.arraycopy(ivBytes, 0, finalCiphertext, 0, 16);
System.arraycopy(salt, 0, finalCiphertext, 16, 16);
System.arraycopy(encValue, 0, finalCiphertext, 32, encValue.length);
return finalCiphertext;
其他要记住的事项：
Other things to keep in mind:
- 始终使用完全限定的密码名称。在这种情况下，
AES不合适，因为不同的JVM / JCE提供者可能会使用不同的默认值作为操作和填充。使用AES / CBC / PKCS5Padding。不要使用ECB模式，因为它不是语义上安全的。 - 如果不使用ECB模式，则需要发送IV和密文。这通常通过将IV前缀到密文字节数组来完成。 IV自动为您创建，您可以通过
cipherInstance.getIV（）获取它。 - 每当你发送东西，你需要确保沿途没有改变。用MAC正确实现加密是很困难的。我建议您使用CCM或GCM等认证模式。
- Always use a fully qualified Cipher name.
AESis not appropriate in such a case, because different JVMs/JCE providers may use different defaults for mode of operation and padding. UseAES/CBC/PKCS5Padding. Don't use ECB mode, because it is not semantically secure. - If you don't use ECB mode then you need to send the IV along with the ciphertext. This is usually done by prefixing the IV to the ciphertext byte array. The IV is automatically created for you and you can get it through
cipherInstance.getIV(). - Whenever you send something, you need to be sure that it wasn't altered along the way. It is hard to implement a encryption with MAC correctly. I recommend you to use an authenticated mode like CCM or GCM.
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