关于AES加密（下）

上期提供了Java中AES加密，因为在使用时，一般Java作为服务器或者终端，可能涉及到ios作为终端，至少我遇到的场景是这样的，所以贴上IOS端的AES加密。首先我下面的代码是基于NSData的Category；上代码吧：

NSData+AES256.h

#import <Foundation/Foundation.h>#import <CommonCrypto/CommonCryptor.h>#import <CommonCrypto/CommonKeyDerivation.h>@interface NSData (AES256)+ (NSData *)AES256EncryptWithPlainText:(NSString *)plain;        /*加密方法,参数需要加密的内容*/+ (NSData *)AES256DecryptWithCiphertext:(NSString *)ciphertexts; /*解密方法，参数数密文*/@end

NSData+AES256.m

#import "NSData+AES256.h"#define PASSWORD @"Per vallum duces Labant"static const char encodingTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";const NSUInteger kAlgorithmKeySize = kCCKeySizeAES256;const NSUInteger kPBKDFRounds = 10000;  // ~80ms on an iPhone 4//static Byte saltBuff[] = {0,1,2,3,4,5,6,7,8,9,0xA,0xB,0xC,0xD,0xE,0xF};static NSString *key = @"H@}+T@b}hS/5798DGILXURXp'o$cC%!XpOibP N6Gg@1um*kAS; [7y&BcSSo+m*";static Byte ivBuff[]   = {0xA,1,0xB,5,4,0xF,7,9,0x17,3,1,6,8,0xC,0xD,91};@implementation NSData (AES256)+ (NSData *)AESKeyForPassword:(NSString *)password{                  //Derive a key from a text password/passphrase        NSMutableData *derivedKey = [NSMutableData dataWithLength:kAlgorithmKeySize];        //NSData *salt = [NSData dataWithBytes:saltBuff length:kCCKeySizeAES128];        NSData *salt = [key dataUsingEncoding:NSUTF8StringEncoding];        int result = CCKeyDerivationPBKDF(kCCPBKDF2,        // algorithm算法                                  password.UTF8String,  // password密码                                  password.length,      // passwordLength密码的长度                                  salt.bytes,           // salt内容                                  salt.length,          // saltLen长度                                  kCCPRFHmacAlgSHA1,    // PRF                                  kPBKDFRounds,         // rounds循环次数                                  derivedKey.mutableBytes, // derivedKey                                  derivedKey.length);   // derivedKeyLen derive:出自        NSAssert(result == kCCSuccess,             @"Unable to create AES key for spassword: %d", result);    return derivedKey;}/*加密方法*/+ (NSData*)AES256EncryptWithPlainText:(NSString *)plain {    NSData *plainText = [plain dataUsingEncoding:NSUTF8StringEncoding];// 'key' should be 32 bytes for AES256, will be null-padded otherwisechar keyPtr[kCCKeySizeAES256+1]; // room for terminator (unused)bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)        NSUInteger dataLength = [plainText length];size_t bufferSize = dataLength + kCCBlockSizeAES128;void *buffer = malloc(bufferSize);    bzero(buffer, sizeof(buffer));size_t numBytesEncrypted = 0;    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128,kCCOptionPKCS7Padding,                                          [[NSData AESKeyForPassword:PASSWORD] bytes], kCCKeySizeAES256,  ivBuff /* initialization vector (optional) */,  [plainText bytes], dataLength, /* input */  buffer, bufferSize, /* output */  &numBytesEncrypted);if (cryptStatus == kCCSuccess) {        NSData *encryptData = [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];        NSLog(@"%@", [encryptData base64Encoding]);return encryptData;}free(buffer); //free the buffer;return nil;}/*解密方法*/+ (NSData *)AES256DecryptWithCiphertext:(NSString *)ciphertexts{        NSData *cipherData = [NSData dataWithBase64EncodedString:ciphertexts];// 'key' should be 32 bytes for AES256, will be null-padded otherwisechar keyPtr[kCCKeySizeAES256+1]; // room for terminator (unused)bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)    NSUInteger dataLength = [cipherData length];size_t bufferSize = dataLength + kCCBlockSizeAES128;void *buffer = malloc(bufferSize);    size_t numBytesDecrypted = 0;CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,  [[NSData AESKeyForPassword:PASSWORD] bytes], kCCKeySizeAES256,  ivBuff ,/* initialization vector (optional) */  [cipherData bytes], dataLength, /* input */  buffer, bufferSize, /* output */  &numBytesDecrypted);if (cryptStatus == kCCSuccess) {        NSData *encryptData = [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];return encryptData;}free(buffer); //free the buffer;return nil;}+ (id)dataWithBase64EncodedString:(NSString *)string;{    if (string == nil)        [NSException raise:NSInvalidArgumentException format:nil];    if ([string length] == 0)        return [NSData data];        static char *decodingTable = NULL;    if (decodingTable == NULL)    {        decodingTable = malloc(256);        if (decodingTable == NULL)            return nil;        memset(decodingTable, CHAR_MAX, 256);        NSUInteger i;        for (i = 0; i < 64; i++)            decodingTable[(short)encodingTable[i]] = i;    }        const char *characters = [string cStringUsingEncoding:NSASCIIStringEncoding];    if (characters == NULL)     //  Not an ASCII string!        return nil;    char *bytes = malloc((([string length] + 3) / 4) * 3);    if (bytes == NULL)        return nil;    NSUInteger length = 0;        NSUInteger i = 0;    while (YES)    {        char buffer[4];        short bufferLength;        for (bufferLength = 0; bufferLength < 4; i++)        {            if (characters[i] == '\0')                break;            if (isspace(characters[i]) || characters[i] == '=')                continue;            buffer[bufferLength] = decodingTable[(short)characters[i]];            if (buffer[bufferLength++] == CHAR_MAX)      //  Illegal character!            {                free(bytes);                return nil;            }        }                if (bufferLength == 0)            break;        if (bufferLength == 1)      //  At least two characters are needed to produce one byte!        {            free(bytes);            return nil;        }                //  Decode the characters in the buffer to bytes.        bytes[length++] = (buffer[0] << 2) | (buffer[1] >> 4);        if (bufferLength > 2)            bytes[length++] = (buffer[1] << 4) | (buffer[2] >> 2);        if (bufferLength > 3)            bytes[length++] = (buffer[2] << 6) | buffer[3];    }        bytes = realloc(bytes, length);    return [NSData dataWithBytesNoCopy:bytes length:length];}- (NSString *)base64Encoding;{    if ([self length] == 0)        return @"";        char *characters = malloc((([self length] + 2) / 3) * 4);    if (characters == NULL)        return nil;    NSUInteger length = 0;        NSUInteger i = 0;    while (i < [self length])    {        char buffer[3] = {0,0,0};        short bufferLength = 0;        while (bufferLength < 3 && i < [self length])            buffer[bufferLength++] = ((char *)[self bytes])[i++];                //  Encode the bytes in the buffer to four characters, including padding "=" characters if necessary.        characters[length++] = encodingTable[(buffer[0] & 0xFC) >> 2];        characters[length++] = encodingTable[((buffer[0] & 0x03) << 4) | ((buffer[1] & 0xF0) >> 4)];        if (bufferLength > 1)            characters[length++] = encodingTable[((buffer[1] & 0x0F) << 2) | ((buffer[2] & 0xC0) >> 6)];        else characters[length++] = '=';        if (bufferLength > 2)            characters[length++] = encodingTable[buffer[2] & 0x3F];        else characters[length++] = '=';        }        return [[[NSString alloc] initWithBytesNoCopy:characters length:length encoding:NSASCIIStringEncoding freeWhenDone:YES] autorelease];}@end