生成哈希字符串

+ (NSString *)getSha1String:(
NSString *)srcString{

const
char *cstr = [srcString
cStringUsingEncoding : NSUTF8StringEncoding ];

NSData *data = [ NSData
dataWithBytes :cstr
length :srcString. length ];

uint8_t digest [ CC_SHA1_DIGEST_LENGTH]; / 20: * digest length in bytes */

CC_SHA1 (data.bytes , data.length , digest);

NSMutableString * result = [
NSMutableString stringWithCapacity :
CC_SHA1_DIGEST_LENGTH *
2 ];

for ( int i =
0 ; i < CC_SHA1_DIGEST_LENGTH ; i++) {

[result
appendFormat : @"%02x" , digest[i]];

}

return result;
}