Two kinds of MD5 encryption methods in Android environment

in peacetime development process, MD5 encryption is a more commonly used algorithm, the most common use scenario is in the Account Register, the user input password by MD5 encryption, transfer to the server to save. Although MD5 encryption is often used. But MD5 's encryption principle I really can not say, the cognition of MD5 now only stay in the level that will use. It's going to take some time to figure it out. This is an introduction to the MD5 encryption algorithm. This paper mainly introduces two kinds of MD5 encryption methods under the Android platform, namely MD5 encryption based on Java language and MD5 encryption based on C language in NDK environment.

The following code is the Java-language-based MD5 encryption:

public string getMD5 (string info) {Try{messagedigest MD5 = messagedigest.getinstance ("MD5"); Md5.update (Info.getbytes ( "UTF-8")); byte[] encryption = Md5.digest ();  StringBuffer strbuf = new StringBuffer (); for (int i = 0; i < encryption.length; i++) {if (Integer.tohexstring (0xFF & Encryption[i]). Length () = = 1) {strbuf.append ("0"). Append (integer.tohexstring (0xFF & Encryption[i]);} Else{strbuf.append (integer.tohexstring (0xFF & Encryption[i));}} return strbuf.tostring ();} catch (NoSuchAlgorithmException e) {return "";} catch (Unsupportedencodingexception e) {return "";}}

The following code is the C-based MD5 encryption in the NDK environment:

#include <jni.h> #include <stdio.h> #include <string.h> #include "md5.h"//MD5 encryption Jniexport jstring Jnicall java_com_example_testmd5_mainactivity_encryptbymd5 (jnienv *env, Jclass obj, jstring strText) {char* SzText = ( char*) (*env)->getstringutfchars (env, strText, 0); Md5_ctx context = {0}; Md5init (&context); Md5update (&context, Sztext, strlen (sztext)); unsigned char dest[16] = {0}; Md5final (dest, &context);(*env)->releasestringutfchars (env, StrText, sztext); int i = 0;char szmd5[32] = {0};for ( i = 0; I < 16; i++) {sprintf (szMd5, "%s%02x", SzMd5, Dest[i]);} Return (*ENV)->newstringutf (env, SZMD5);}

just the above code is only part of the, because the MD5 encryption algorithm C source code file is longer, it is not shown here. Students who want to study can download the full Project view, Project download link is: http://download.csdn.net/detail/u013085897/8097613. Project execution results such as what you see, Hello World is the string to be encrypted.

Two kinds of MD5 encryption methods in Android environment