Symbian 计算 MD5

核心提示：从MD5 HexDigest for Symbian看到的代码LOCAL_C HBufC8* Md5HexDigestLC(const TDes8& aString){CMD5* md5 = CMD5::NewL();CleanupStack::PushL(md5);TPtrC8 hashedSig(md5->H

从MD5 HexDigest for Symbian看到的代码

LOCAL_C HBufC8* Md5HexDigestLC(const TDes8& aString)

{

CMD5* md5 = CMD5::NewL();

CleanupStack::PushL(md5);

TPtrC8 hashedSig(md5->Hash(aString));

HBufC8* buf = HBufC8::NewL(hashedSig.Length() * 2);

TPtr8 bufPtr = buf->Des();

for(TInt i=0; i< hashedSig.Length(); i++)

{

bufPtr.AppendFormat(_L8(“%+02x”),hashedSig[i]);

}

CleanupStack::PopAndDestroy(md5);

CleanupStack::PushL(buf);

return buf;

}

改成更简单的

LOCAL_C HBufC8* DoMD5(const TDes8& aString)

{

CMD5* MD5 = CMD5::NewL();

CleanupStack::PushL(MD5);

HBufC8 *HashSigned=(MD5->Hash(aFileName)).AllocL();

//TPtrC8 bytes = md5->Hash(aSource);

CleanupStack::PopAndDestroy(MD5);

return HashSigned;

}

注意:

CMD5包含头文件hash.h,并需要链接hash.lib

LOCAL_C void Md5HexDigestLC(const TDes8& aString)

{

CMD5* md5 = CMD5::NewL();

CleanupStack::PushL(md5);

TPtrC8 hashedSig = md5->Hash(aString);

CleanupStack::PopAndDestroy(md5);

}

我们看看IDA反汇编出来的结果

PUSH {R4,R5,LR}

SUB SP, SP, #0xC

MOVS R5, R0

BLX _ZN4CMD54NewLEv ; CMD5::NewL(void)

MOVS R4, R0

BLX _ZN12CleanupStack5PushLEP5CBase ; CleanupStack::PushL(CBase *)

LDR R3, [R4]

MOV R0, SP

MOVS R2, R5

LDR R3, [R3,#0x10]

MOVS R1, R4

BLX R3 ;这里就是调用 md5->Hash()

BLX _ZN12CleanupStack13PopAndDestroyEv ; CleanupStack::PopAndDestroy(void)

ADD SP, SP, #0xC

POP {R4,R5,PC}

类似地, 下面的这段代码,是从某个实际的应用程序中提取到的

LDR R12, [R7,#4] ; 载入md5对象

MOV R0, R8

MOV R2, R4

MOV R1, R12

LDR R3, [R12] ; 读取虚函数表指针

MOV LR, PC ; 保存返回地址

LDR PC, [R3,#0x10] ; 调用hash的虚函数