本文是自己阅读了网上的高人们的文章之后，实现功能后总结出来的，方便自己方便他人，不喜勿喷
加密解密需要生成公钥、私钥文件步骤
1.打开终端 输入
openssl
5F88AA4A-3913-4CBC-9307-00ED47557FCD.png
2.生成私钥文件
输入：
genrsa -out private_key.pem 1024
genrsa:指定了生成了算法使用RSA
-out:后面的参数表示生成的key的输入文件
1024:表示的是生成key的长度,单位字节(bits)
EC31F55E-1142-49CD-A3B9-BBF435950F27.png
D9AD9E8E-43EE-4352-A2CC-A3787076AC51.png
若找不到该文件可全局搜索该名字
3.创建证书请求
输入：
req -new -key private_key.pem -out rsaCertReq.csr
会让输入一些信息，可填可不填
4405C579-7C91-4F72-A8C8-B23727AC9F4F.png
4.生成证书并签名，有效期10年
输入：
x509 -req -days 3650 -in rsaCertReq.csr -signkey private_key.pem -out rsaCert.crt
41C14307-493D-417B-967E-8CA6196A1344.png
5.转换格式 将 PEM 格式文件 转换成 DER 格式 ，此为公钥文件，项目中用得到
输入：
x509 -outform der -in rsaCert.crt -out public_key.der
0DBCD317-806A-4779-BA19-8E2C060CEEA0.png
9E1FB8E4-DBAA-425F-8879-3A839A09234A.png
6.导出 P12 文件，此为私钥文件。项目中用得到
输入：
pkcs12 -export -out private_key.p12 -inkey private_key.pem -in rsaCert.crt
会让输入密码，记住该密码，程序中会用得到
64F45FBA-74A6-4BF5-A4E1-88D324057E0B.png
7.给Java创建 rsa_public_key.pem
输入：
rsa -in private_key.pem -out rsa_public_key.pem -pubout
8.给Java创建 pkcs8_private_key.pem
输入：
pkcs8 -topk8 -in private_key.pem -out pkcs8_private_key.pem -nocrypt
CC811457-3CDB-43C7-ACA1-3150602A845F.png
证书已经创建完毕
DBB2A1A7-E042-4860-BF39-FFC524D08F8F.png
iOS使用证书
先请你把 public_key.der 和 private_key.p12 拖进你的Xcode项目里去
同时引入 Security.framework 以及 NSData+Base64.h/m （github可下载）到项目里。
为了使用方便，可引入工具类，代码如下：
@interface RSAEncryptor : NSObject
-(void) loadPublicKeyFromFile: (NSString*) derFilePath;
-(void) loadPublicKeyFromData: (NSData*) derData;
-(void) loadPrivateKeyFromFile: (NSString*) p12FilePath password:(NSString*)p12Password;
-(void) loadPrivateKeyFromData: (NSData*) p12Data password:(NSString*)p12Password;
-(NSString*) rsaEncryptString:(NSString*)string;
-(NSData*) rsaEncryptData:(NSData*)data ;
-(NSString*) rsaDecryptString:(NSString*)string;
-(NSData*) rsaDecryptData:(NSData*)data;
+(void) setSharedInstance: (RSAEncryptor*)instance;
+(RSAEncryptor*) sharedInstance;
@end
#import "RSAEncryptor.h"
#import "Base64.h"
#import <Security/Security.h>
@implementation RSAEncryptor
{
SecKeyRef publicKey;
SecKeyRef privateKey;
}
-(void)dealloc
{
CFRelease(publicKey);
CFRelease(privateKey);
}
-(SecKeyRef) getPublicKey {
return publicKey;
}
-(SecKeyRef) getPrivateKey {
return privateKey;
}
-(void) loadPublicKeyFromFile: (NSString*) derFilePath
{
NSData *derData = [[NSData alloc] initWithContentsOfFile:derFilePath];
[self loadPublicKeyFromData: derData];
}
-(void) loadPublicKeyFromData: (NSData*) derData
{
publicKey = [self getPublicKeyRefrenceFromeData: derData];
}
-(void) loadPrivateKeyFromFile: (NSString*) p12FilePath password:(NSString*)p12Password
{
NSData *p12Data = [NSData dataWithContentsOfFile:p12FilePath];
[self loadPrivateKeyFromData: p12Data password:p12Password];
}
-(void) loadPrivateKeyFromData: (NSData*) p12Data password:(NSString*)p12Password
{
privateKey = [self getPrivateKeyRefrenceFromData: p12Data password: p12Password];
}
#pragma mark - Private Methods
-(SecKeyRef) getPublicKeyRefrenceFromeData: (NSData*)derData
{
SecCertificateRef myCertificate = SecCertificateCreateWithData(kCFAllocatorDefault, (__bridge CFDataRef)derData);
SecPolicyRef myPolicy = SecPolicyCreateBasicX509();
SecTrustRef myTrust;
OSStatus status = SecTrustCreateWithCertificates(myCertificate,myPolicy,&myTrust);
SecTrustResultType trustResult;
if (status == noErr) {
status = SecTrustEvaluate(myTrust, &trustResult);
}
SecKeyRef securityKey = SecTrustCopyPublicKey(myTrust);
CFRelease(myCertificate);
CFRelease(myPolicy);
CFRelease(myTrust);
return securityKey;
}
-(SecKeyRef) getPrivateKeyRefrenceFromData: (NSData*)p12Data password:(NSString*)password
{
SecKeyRef privateKeyRef = NULL;
NSMutableDictionary * options = [[NSMutableDictionary alloc] init];
[options setObject: password forKey:(__bridge id)kSecImportExportPassphrase];
CFArrayRef items = CFArrayCreate(NULL, 0, 0, NULL);
OSStatus securityError = SecPKCS12Import((__bridge CFDataRef) p12Data, (__bridge CFDictionaryRef)options, &items);
if (securityError == noErr && CFArrayGetCount(items) > 0) {
CFDictionaryRef identityDict = CFArrayGetValueAtIndex(items, 0);
SecIdentityRef identityApp = (SecIdentityRef)CFDictionaryGetValue(identityDict, kSecImportItemIdentity);
securityError = SecIdentityCopyPrivateKey(identityApp, &privateKeyRef);
if (securityError != noErr) {
privateKeyRef = NULL;
}
}
CFRelease(items);
return privateKeyRef;
}
#pragma mark - Encrypt
-(NSString*) rsaEncryptString:(NSString*)string {
NSData* data = [string dataUsingEncoding:NSUTF8StringEncoding];
NSData* encryptedData = [self rsaEncryptData: data];
NSString* base64EncryptedString = [encryptedData base64EncodedString];
return base64EncryptedString;
}
// 加密的大小受限于SecKeyEncrypt函数，SecKeyEncrypt要求明文和密钥的长度一致，如果要加密更长的内容，需要把内容按密钥长度分成多份，然后多次调用SecKeyEncrypt来实现
-(NSData*) rsaEncryptData:(NSData*)data {
SecKeyRef key = [self getPublicKey];
size_t cipherBufferSize = SecKeyGetBlockSize(key);
uint8_t *cipherBuffer = malloc(cipherBufferSize * sizeof(uint8_t));
size_t blockSize = cipherBufferSize - 11; // 分段加密
size_t blockCount = (size_t)ceil([data length] / (double)blockSize);
NSMutableData *encryptedData = [[NSMutableData alloc] init] ;
for (int i=0; i<blockCount; i++) {
int bufferSize = MIN(blockSize,[data length] - i * blockSize);
NSData *buffer = [data subdataWithRange:NSMakeRange(i * blockSize, bufferSize)];
OSStatus status = SecKeyEncrypt(key, kSecPaddingPKCS1, (const uint8_t *)[buffer bytes], [buffer length], cipherBuffer, &cipherBufferSize);
if (status == noErr){
NSData *encryptedBytes = [[NSData alloc] initWithBytes:(const void *)cipherBuffer length:cipherBufferSize];
[encryptedData appendData:encryptedBytes];
}else{
if (cipherBuffer) {
free(cipherBuffer);
}
return nil;
}
}
if (cipherBuffer){
free(cipherBuffer);
}
return encryptedData;
}
#pragma mark - Decrypt
-(NSString*) rsaDecryptString:(NSString*)string {
NSData *data = [NSData dataWithBase64EncodedString:string];
// NSData* data = [NSData dataFromBase64String: string];
NSData* decryptData = [self rsaDecryptData: data];
NSString* result = [[NSString alloc] initWithData: decryptData encoding:NSUTF8StringEncoding];
return result;
}
-(NSData*) rsaDecryptData:(NSData*)data {
SecKeyRef key = [self getPrivateKey];
size_t cipherLen = [data length];
void *cipher = malloc(cipherLen);
[data getBytes:cipher length:cipherLen];
size_t plainLen = SecKeyGetBlockSize(key) - 12;
void *plain = malloc(plainLen);
OSStatus status = SecKeyDecrypt(key, kSecPaddingPKCS1, cipher, cipherLen, plain, &plainLen);
if (status != noErr) {
return nil;
}
NSData *decryptedData = [[NSData alloc] initWithBytes:(const void *)plain length:plainLen];
return decryptedData;
}
#pragma mark - Class Methods
static RSAEncryptor* sharedInstance = nil;
+(void) setSharedInstance: (RSAEncryptor*)instance
{
sharedInstance = instance;
}
+(RSAEncryptor*) sharedInstance
{
return sharedInstance;
}
@end
即可使用RSA加密解密
//配置秘钥
RSAEncryptor* rsaEncryptor = [[RSAEncryptor alloc] init];
NSString* publicKeyPath = [[NSBundle mainBundle] pathForResource:@"public_key" ofType:@"der"];
NSString* privateKeyPath = [[NSBundle mainBundle] pathForResource:@"private_key" ofType:@"p12"];
[rsaEncryptor loadPublicKeyFromFile: publicKeyPath];
[rsaEncryptor loadPrivateKeyFromFile: privateKeyPath password:@"生成p12时的密码"]; // 换成你生成p12时的密码
//字符串RSA加密
NSString *string = @"RSA加密字符串";
NSString* restrinBASE64STRING = [rsaEncryptor rsaEncryptString:string];
NSLog(@"加密后：==== %@", restrinBASE64STRING);
//字符串RSA解密
NSString* decryptString = [rsaEncryptor rsaDecryptString: restrinBASE64STRING];
NSLog(@"解密后：==== %@", decryptString);
运行结果
6307CA8C-8B57-46FA-AC35-29F66C24CC77.png
参考：
http://www.cnblogs.com/yangxiaolong/p/5526765.html
http://blog.csdn.net/yi_zz32/article/details/50097325
如果没有解决问题，推荐看下一篇文章
RSA 加密、解密(服务器给公钥，剩下的自己搞)
http://www.jianshu.com/p/f4497d19f336
