iPhone开发中 验证”字符串“/“文件”的MD5的加密

+(NSString*) md5:(NSString*) str
{
const char *cStr = [str UTF8String];
unsigned char result[CC_MD5_DIGEST_LENGTH];
CC_MD5( cStr, strlen(cStr), result );

NSMutableString *hash = [NSMutableString string];
for(int i=0;i<CC_MD5_DIGEST_LENGTH;i++)
{
[hash appendFormat:@"%02X",result[i]];
}
return [hash lowercaseString];
}
#define CHUNK_SIZE 1024
+(NSString *)file_md5:(NSString*) path
{
NSFileHandle* handle = [NSFileHandle fileHandleForReadingAtPath:path];
if(handle == nil)
return nil;

CC_MD5_CTX md5_ctx;
CC_MD5_Init(&md5_ctx);

NSData* filedata;
do {
filedata = [handle readDataOfLength:CHUNK_SIZE];
CC_MD5_Update(&md5_ctx, [filedata bytes], [filedata length]);
}
while([filedata length]);

unsigned char result[CC_MD5_DIGEST_LENGTH];
CC_MD5_Final(result, &md5_ctx);

[handle closeFile];

NSMutableString *hash = [NSMutableString string];
for(int i=0;i<CC_MD5_DIGEST_LENGTH;i++)
{
[hash appendFormat:@"%02x",result[i]];
}
return [hash lowercaseString];
}

+(NSString *)NSStringToMD5String:(NSString *)str{
NSString *result = nil;
if(str) {
unsigned char digest[16];
const char *cStr=[str UTF8String];
CC_MD5(cStr, strlen(cStr), digest);

result = [NSString stringWithFormat: @"%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
digest[0], digest[1],
digest[2], digest[3],
digest[4], digest[5],
digest[6], digest[7],
digest[8], digest[9],
digest[10], digest[11],
digest[12], digest[13],
digest[14], digest[15]];
result = [result uppercaseString];
}
return result;
}