include <CommonCrypto/CommonDigest.h>

//Base64加密
+(NSString *)encodeBase64:(NSString *)input {
NSData *data = [input dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];
data = [GTMBase64 encodeData:data];
NSString *base64String = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(@"encodeBase64 == %@",base64String);
return base64String;
}

//Base64编码
+(NSString *)base64EncodeString:(NSString *)string {
//1.先把字符串转换为二进制数据
NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
//2.对二进制数据进行base64编码，返回编码后的字符串
//这是苹果已经给我们提供的方法
NSString *str = [data base64EncodedStringWithOptions:0];
return str;
}

//Base64解密
+(NSString *)decodeBase64:(NSString *)input {
NSData *data = [input dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];
data = [GTMBase64 decodeData:data];
NSString *base64String = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(@"decodeBase64 == %@",base64String);
return base64String;
}

//对base64编码后的字符串进行解码
+(NSString *)base64DecodeString:(NSString *)string {
//1.将base64编码后的字符串『解码』为二进制数据
//这是苹果已经给我们提供的方法
NSData *data = [[NSData alloc]initWithBase64EncodedString:string options:0];
//2.把二进制数据转换为字符串返回
NSString *str = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
return str;
}

//Base64 字符串解码成 字符串
+(NSString *)decodeBase64ToHexString:(NSString *)input {
//1.将base64编码后的字符串『解码』为二进制数据
//这是苹果已经给我们提供的方法
NSData *myD = [[NSData alloc]initWithBase64EncodedString:input options:0];
Byte *bytes = (Byte *)[myD bytes];
//下面是Byte 转换为16进制。
NSString *hexStr=@"";
for(int i=0;i<[myD length];i++) {
NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes[i]&0xff];///16进制数
if([newHexStr length]==1)
hexStr = [NSString stringWithFormat:@"%@0%@",hexStr,newHexStr];
else
hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr];
}
return hexStr;
}

//DES 加密
+(NSData *)encryptUseDES:(NSData *)plainText key:(Byte *)key {
NSData *textData = plainText;
NSUInteger dataLength = [textData length];
unsigned char buffer[1024];
memset(buffer, 0, sizeof(char));
size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmDES,
kCCOptionECBMode,
key, kCCKeySizeDES,
nil,
[textData bytes], dataLength,
buffer, 1024,
&numBytesEncrypted);
if (cryptStatus == kCCSuccess) {
NSData *data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];
return data;
}
return nil;
}

//DES 解密
+(NSData *)decrypUseDES:(NSData *)plainText key:(Byte *)key {
NSData *cipherdata = plainText;
unsigned char buffer[1024];
memset(buffer, 0, sizeof(char));
size_t numBytesDecrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmDES,
kCCOptionECBMode,
key, kCCKeySizeDES,
nil,
[cipherdata bytes], [cipherdata length],
buffer, 1024,
&numBytesDecrypted);
if(cryptStatus == kCCSuccess) {
NSData *plaindata = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesDecrypted];
return plaindata;
}
return nil;
}

/MD5加密返回Nsdata
+(NSData *)encodeMD5:(NSData *)input {
unsigned char result[CC_MD5_DIGEST_LENGTH];
CC_MD5(input.bytes, (CC_LONG)input.length, result);
NSData *data =[[NSData alloc] initWithBytes:result length:CC_MD5_DIGEST_LENGTH];
return data;
}

如下，生成是小写的MD5的字符串，如果要生成大写的，只需要把
[ret appendFormat:@"%02X",result[i]];中的 "%02X"的 X改成小写的 x即可。

//MD5加密返回Nsstring
+(NSString *)MD5HexDigest:(NSData *)input {
unsigned char result[CC_MD5_DIGEST_LENGTH];
CC_MD5(input.bytes, (CC_LONG)input.length, result);
NSMutableString ret = [NSMutableString stringWithCapacity:CC_MD5_DIGEST_LENGTH2];
for (int i = 0; i<CC_MD5_DIGEST_LENGTH; i++) {
[ret appendFormat:@"%02X",result[i]];
}
return ret;
}