android– 加密(AES)

概述我使用AES算法来加密我的数据.当我加密16字节(一个块)时,结果是32字节.我期望16字节,但它生成32字节.如果我以字符串格式使用我的代码,结果是相同的.为什么？我的源代码是packagechert.chert;importchert.chert.R;importchert.chert.SimpleCrypto;importandroid.app.Acti

我使用AES算法来加密我的数据.当我加密16字节(一个块)时,结果是32字节.我期望16字节,但它生成32字节.
如果我以字符串格式使用我的代码,结果是相同的.
为什么？

我的源代码是

package chert.chert;import chert.chert.R;import chert.chert.SimpleCrypto;import androID.app.Activity;import androID.os.Bundle;import androID.Widget.TextVIEw;public class ChertActivity extends Activity {    /** Called when the activity is first created. */    TextVIEw textVIEw1;    byte[] key=new byte[16];    byte[] state=new byte[16];    public SimpleCrypto Crypt = new SimpleCrypto(this);    @OverrIDe    public voID onCreate(Bundle savedInstanceState) {        int i;        String ss,state_str,key_str;        char c;        super.onCreate(savedInstanceState);        setContentVIEw(R.layout.main);        //======================================================================================================================                state[0]=0x32;           state[1]=(byte) 0x88;  state[2]=0x31;          state[3]=(byte) 0xe0;        state[4]=0x43;           state[5]=0x5a;         state[6]=0x31;          state[7]=0x37;        state[8]=(byte) 0xf6;    state[9]=0x30;         state[10]=(byte) 0x98;  state[11]=0x07;        state[12]=(byte) 0xa8;   state[13]=(byte) 0x8d; state[14]=(byte) 0xa2;  state[15]=0x34;     //======================================================================================================================                key[0]=0x2b;           key[1]=0x28;                key[2]=(byte) 0xab;   key[3]=0x09;        key[4]=0x7e;           key[5]=(byte) 0xae;         key[6]=(byte) 0xf7;   key[7]=(byte) 0xcf;        key[8]=0x15;           key[9]=(byte) 0xd2;         key[10]=0x15;         key[11]=0x4f;        key[12]=0x16;          key[13]=(byte) 0xa6;        key[14]=(byte) 0x88;  key[15]=0x3c;      //======================================================================================================================                try {            byte[] rawKey = Crypt.getRawKey(key);            byte[] result = Crypt.encrypt(rawKey, state);            } catch (Exception e) {                e.printstacktrace();            }    }}package chert.chert;import java.security.SecureRandom;import javax.crypto.Cipher;import javax.crypto.KeyGenerator;import javax.crypto.SecretKey;import javax.crypto.spec.SecretKeySpec;public class SimpleCrypto {    public SimpleCrypto(ChertActivity chertActivity) {        // Todo auto-generated constructor stub    }    public static String encrypt(String seed, String cleartext) throws Exception {        byte[] rawKey = getRawKey(seed.getBytes());        byte[] result = encrypt(rawKey, cleartext.getBytes());        return toHex(result);    }    public static String decrypt(String seed, String encrypted) throws Exception {        byte[] rawKey = getRawKey(seed.getBytes());        byte[] enc = toByte(encrypted);        byte[] result = decrypt(rawKey, enc);        return new String(result);    }    public static byte[] getRawKey(byte[] seed) throws Exception {        KeyGenerator kgen = KeyGenerator.getInstance("AES");        SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");        sr.setSeed(seed);        kgen.init(128, sr); // 192 and 256 bits may not be available        SecretKey skey = kgen.generateKey();        byte[] raw = skey.getEncoded();        return raw;    }    public static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");        Cipher cipher = Cipher.getInstance("AES");        cipher.init(Cipher.ENCRYPT_MODE, skeySpec);        byte[] encrypted = cipher.doFinal(clear);        return encrypted;    }    private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");        Cipher cipher = Cipher.getInstance("AES");        cipher.init(Cipher.DECRYPT_MODE, skeySpec);        byte[] decrypted = cipher.doFinal(encrypted);        return decrypted;    }    public static String toHex(String txt) {        return toHex(txt.getBytes());    }    public static String fromHex(String hex) {        return new String(toByte(hex));    }    public static byte[] toByte(String hexString) {        int len = hexString.length()/2;        byte[] result = new byte[len];        for (int i = 0; i < len; i++)            result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();        return result;    }    public static String toHex(byte[] buf) {        if (buf == null)            return "";        StringBuffer result = new StringBuffer(2*buf.length);        for (int i = 0; i < buf.length; i++) {            appendHex(result, buf[i]);        }        return result.toString();    }    private final static String HEX = "0123456789ABCDEF";    private static voID appendHex(StringBuffer sb, byte b) {        sb.append(HEX.charat((b>>4)&0x0f)).append(HEX.charat(b&0x0f));    }}

解决方法:

如果明文的长度是块大小的倍数,则根据PKCS#5,填充需要一个全新的块.假设您的明文是16个字节.密文将占用32个字节.

它类似于以下内容

CipherTextLength = (PlainTextLength / 16 + 1) * 16;

总结

以上是内存溢出为你收集整理的android – 加密(AES)全部内容，希望文章能够帮你解决android – 加密(AES)所遇到的程序开发问题。

如果觉得内存溢出网站内容还不错，欢迎将内存溢出网站推荐给程序员好友。