自定义MD5加密

#import <CommonCrypto/CommonDigest.h>

+ (NSString *) md5:(NSString *)oldString {
    
    const char *cStr = [oldString UTF8String];
    unsigned char result[16];
    CC_MD5( cStr, strlen(cStr), result );
    unsigned char str[32];
    char hexDigits[]={'2','0','1','5','V','T','H','A','P','P','0','6','A','T','0','1'};
    int k = 0;
    for (int i = 0; i < 16; i++) {
        Byte byte0 = result[i];
        str[k++] = hexDigits[byte0>>4& 0xf];
        str[k++] = hexDigits[byte0 & 0xf];
    }
    
    NSString *mdString =@"";
    for (int i=0; i<32; i++) {
        
       mdString= [mdString stringByAppendingString:[NSString stringWithFormat:@"%c",str[i]]];
    }
    
    
    return mdString;
}

public static String getEncryptedStr(String s) {
	        char hexDigits[]={'2','0','1','5','V','T','H','A','P','P','0','6','A','T','0','1'};   

	        try {
	            byte[] btInput = s.getBytes();
	            // 获得MD5摘要算法的 MessageDigest 对象
	            MessageDigest mdInst = MessageDigest.getInstance("MD5");
	            // 使用指定的字节更新摘要
	            mdInst.update(btInput);
	            // 获得密文
	            byte[] md = mdInst.digest();
	            // 把密文转换成十六进制的字符串形式
	            int j = md.length;
	            char str[] = new char[j * 2];
	            int k = 0;
	            for (int i = 0; i < j; i++) {
	                byte byte0 = md[i];
	                str[k++] = hexDigits[byte0 >>> 4 & 0xf];
	                str[k++] = hexDigits[byte0 & 0xf];
	            }
	            return new String(str);
	        } catch (Exception e) {
	            e.printStackTrace();
	            return null;
	        }
	    }