iOS开发中MD5加密方式

将MD5的加密方式写成NSString的Category的方式，下边是.h 和 .m的实现
#import <Foundation/Foundation.h>
#import <CommonCrypto/CommonDigest.h>

@interface NSString (MD5)
- (NSString *)stringFromMD5;
@end

#import "NSString+MD5.h"
@implementation NSString (MD5)
- (NSString *)stringFromMD5
{
if (self ==
nil || [self
length] == 0) {
return
nil;
}
const
char *value = [self
UTF8String];
unsigned
char outputBuffer[CC_MD4_DIGEST_LENGTH];
CC_MD5(value,
strlen(value),outputBuffer);
NSMutableString *outputString = [NSMutableString
stringWithCapacity:CC_MD5_DIGEST_LENGTH*2];
for (int i=0; i<CC_MD5_DIGEST_LENGTH;
i++) {
[outputString appendFormat:@"%02x",outputBuffer[i]];
}
return outputString;
}
@end