欢迎挑战:一个反编译的后的函数计算结果出错的问题

我曾经使用 dex2jar 反编译了某一个Android 应用.
然后,导入 Jar,然后一些类可以正常使用,OK
但是,仔细检查发现了问题:
就是反编译后的结果与应用之前计算的结果不同.
比如如下反编译后的EncryptUtil 类中方法:

public static String toParam(String var0, String var1) {
        try {
            String var3 = "param=" + of_encrypt(var0, var1) + "&param2=" + getMd5_2(var0);
            return var3;
        } catch (Exception var4) {
            return "param=error&param2=error";
        }
    }

对于以下代码:

System.out.println("myAllParams="+EncryptUtil.toParam(originalParam1,xxdm));
System.out.println("myAllParams2="+EncryptUtil.toParam(originalParam1,xxdm));
System.out.println("myParam2_1="+EncryptUtil.getMd5_2(param));
System.out.println("myParam2_2="+EncryptUtil.getMd5_2(param));

按道理,也就是 toParam 方法调用之后的 param2的结果, 应该与直接调用 getMd5_2的结果一样,
可以结果确不是一样的.
上面代码输出如下:

myAllParams=param=2tb3nq2qay2o2s45ch2mqawf2twpf52pqe5m1vc4lm1ltd391o6vsm1oseh62ojcs92ridda1tjxn41r68rl1pz0hl2qbqoo2s4j8q2hdhkv291ui72il9zc003erq&param2=6d749a8bf841a5d3d772832367d5c0e6

myAllParams2=param=2tb3nq2qay2o2s45ch2mqawf2twpf52pqe5m1vc4lm1ltd391o6vsm1oseh62ojcs92ridda1tjxn41r68rl1pz0hl2qbqoo2s4j8q2hdhkv291ui72il9zc003erq&param2=6d749a8bf841a5d3d772832367d5c0e6

myParam2_1=7aac8cb9cdf9898077a262d324dd86b5

myParam2_2=7aac8cb9cdf9898077a262d324dd86b5

但是其实上面对于 param2的计算都是错误的
正确的计算结果 ,也就是原来应用的计算结果是:
param2=338f3b6b250342cc5b1117a6346b0c89

直接从反编译出来的代码看不出是什么导致了问题:
但是感觉调用toParam 跟直接调用 getMd5_2有差别

于是尝试分析最原始的 toParam 的 smali 代码
如下:

.method public static toParam(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;
    .locals 3
    .param p0, "as_str"    # Ljava/lang/String;
    .param p1, "as_key"    # Ljava/lang/String;

    .prologue
    .line 34
    :try_start_0
    new-instance v1, Ljava/lang/StringBuilder;

    const-string v2, "param="

    invoke-direct {v1, v2}, Ljava/lang/StringBuilder;-><init>(Ljava/lang/String;)V

    invoke-static {p0, p1}, LEncryptUtil;->of_encrypt(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;

    move-result-object v2

    invoke-virtual {v1, v2}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;

    move-result-object v1

    const-string v2, "&param2="

    invoke-virtual {v1, v2}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;

    move-result-object v1

    invoke-static {p0}, LEncryptUtil;->getMd5_2(Ljava/lang/String;)Ljava/lang/String;

    move-result-object v2

    invoke-virtual {v1, v2}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;

    move-result-object v1

    invoke-virtual {v1}, Ljava/lang/StringBuilder;->toString()Ljava/lang/String;
    :try_end_0
    .catch Ljava/lang/Exception; {:try_start_0 .. :try_end_0} :catch_0

    move-result-object v1

    .line 37
    :goto_0
    return-object v1

    .line 36
    :catch_0
    move-exception v1

    move-object v0, v1

    .line 37
    .local v0, "e":Ljava/lang/Exception;
    const-string v1, "param=error&param2=error"

    goto :goto_0
.end method

还是没有发现可疑的地方
欢迎任何线索,指点