Object-C MD5 And SHA And HMAC-SHA

#import <Foundation/Foundation.h>

@interface NSString (Hash)

@property (readonly) NSString *md5String;
@property (readonly) NSString *sha1String;
@property (readonly) NSString *sha256String;
@property (readonly) NSString *sha512String;

- (NSString *)hmacSHA1StringWithKey:(NSString *)key;
- (NSString *)hmacSHA256StringWithKey:(NSString *)key;
- (NSString *)hmacSHA512StringWithKey:(NSString *)key;

- (NSString *)escapedURLString;

@end

#import "NSString+hash.h"

#import <CommonCrypto/CommonDigest.h>
#import <CommonCrypto/CommonHMAC.h>

@implementation NSString (Hash)

- (NSString *)md5String
{
	const char *string = self.UTF8String;
	int length = (int)strlen(string);
	unsigned char bytes[CC_MD5_DIGEST_LENGTH];
	CC_MD5(string, length, bytes);
	return [self stringFromBytes:bytes length:CC_MD5_DIGEST_LENGTH];
}

- (NSString *)sha1String
{
	const char *string = self.UTF8String;
	int length = (int)strlen(string);
	unsigned char bytes[CC_SHA1_DIGEST_LENGTH];
	CC_SHA1(string, length, bytes);
	return [self stringFromBytes:bytes length:CC_SHA1_DIGEST_LENGTH];
}

- (NSString *)sha256String
{
	const char *string = self.UTF8String;
	int length = (int)strlen(string);
	unsigned char bytes[CC_SHA256_DIGEST_LENGTH];
	CC_SHA256(string, length, bytes);
	return [self stringFromBytes:bytes length:CC_SHA256_DIGEST_LENGTH];
}

- (NSString *)sha512String
{
	const char *string = self.UTF8String;
	int length = (int)strlen(string);
	unsigned char bytes[CC_SHA512_DIGEST_LENGTH];
	CC_SHA512(string, length, bytes);
	return [self stringFromBytes:bytes length:CC_SHA512_DIGEST_LENGTH];
}

- (NSString *)hmacSHA1StringWithKey:(NSString *)key
{
	NSData *keyData = [key dataUsingEncoding:NSUTF8StringEncoding];
	NSData *messageData = [self dataUsingEncoding:NSUTF8StringEncoding];
	NSMutableData *mutableData = [NSMutableData dataWithLength:CC_SHA1_DIGEST_LENGTH];
	CCHmac(kCCHmacAlgSHA1, keyData.bytes, keyData.length, messageData.bytes, messageData.length, mutableData.mutableBytes);
	return [self stringFromBytes:(unsigned char *)mutableData.bytes length:(int)mutableData.length];
}

- (NSString *)hmacSHA256StringWithKey:(NSString *)key
{
	NSData *keyData = [key dataUsingEncoding:NSUTF8StringEncoding];
	NSData *messageData = [self dataUsingEncoding:NSUTF8StringEncoding];
	NSMutableData *mutableData = [NSMutableData dataWithLength:CC_SHA256_DIGEST_LENGTH];
	CCHmac(kCCHmacAlgSHA256, keyData.bytes, keyData.length, messageData.bytes, messageData.length, mutableData.mutableBytes);
	return [self stringFromBytes:(unsigned char *)mutableData.bytes length:(int)mutableData.length];
}

- (NSString *)hmacSHA512StringWithKey:(NSString *)key
{
	NSData *keyData = [key dataUsingEncoding:NSUTF8StringEncoding];
	NSData *messageData = [self dataUsingEncoding:NSUTF8StringEncoding];
	NSMutableData *mutableData = [NSMutableData dataWithLength:CC_SHA512_DIGEST_LENGTH];
	CCHmac(kCCHmacAlgSHA512, keyData.bytes, keyData.length, messageData.bytes, messageData.length, mutableData.mutableBytes);
	return [self stringFromBytes:(unsigned char *)mutableData.bytes length:(int)mutableData.length];
}

#pragma mark - Helpers

- (NSString *)stringFromBytes:(unsigned char *)bytes length:(int)length
{
	NSMutableString *mutableString = @"".mutableCopy;
	for (int i = 0; i < length; i++)
		[mutableString appendFormat:@"%02x", bytes[i]];
	return [NSString stringWithString:mutableString];
}

- (NSString *)escapedURLString
{
    NSString *ret   = self;
    char *src       = (char *)[self UTF8String];
    if (NULL != src)
    {
        NSMutableString *tmp = [NSMutableString string];
        int ind = 0;
        while (ind < strlen(src))   // NOTE: if src is NULL, strlen() will crash.
        {
            if (isalpha(src[ind]) || isnumber(src[ind])) {
                [tmp appendFormat:@"%c", src[ind++]];
            }
            else
            {
                [tmp appendFormat:@"%%%X", (unsigned char)src[ind++]];
            }
        }
        
        ret = tmp;
    }
    return ret;
}

@end