iOS RSA加密以及生成公钥秘钥 pem文件-白红宇

iOS RSA加密以及生成公钥秘钥 pem文件

阅读量：5960 次

发布时间：2019-06-19

本文共 20055 字，大约阅读时间需要 66 分钟。

转载:原地址https://blog.csdn.net/zhangmengleiblog/article/details/51362761

在iOS中使用RSA加密解密，需要用到.der和.p12后缀格式的文件，其中.der格式的文件存放的是公钥（Public key）用于加密，.p12格式的文件存放的是私钥（Private key）用于解密. 首先需要先生成这些文件，然后再将文件导入工程使用，不多说，开始做！

一、使用openssl生成所需秘钥文件

　　生成环境是在mac系统下，使用openssl进行生成，首先打开终端，按下面这些步骤依次来做：

1. 生成模长为1024bit的私钥文件private_key.pem

openssl genrsa -out private_key.pem 1024

2. 生成证书请求文件rsaCertReq.csr

openssl req -new -key private_key.pem -out rsaCerReq.csr

注意：这一步会提示输入国家、省份、mail等信息，可以根据实际情况填写，或者全部不用填写，直接全部敲回车.

3. 生成证书rsaCert.crt，并设置有效时间为10年

openssl x509 -req -days 3650 -in rsaCerReq.csr -signkey private_key.pem -out rsaCert.crt

4. 生成供iOS使用的公钥文件public_key.der

openssl x509 -outform der -in rsaCert.crt -out public_key.der

5. 生成供iOS使用的私钥文件private_key.p12

openssl pkcs12 -export -out private_key.p12 -inkey private_key.pem -in rsaCert.crt

注意：这一步会提示给私钥文件设置密码，直接输入想要设置密码即可，然后敲回车，然后再验证刚才设置的密码，再次输入密码，然后敲回车，完毕！

在解密时，private_key.p12文件需要和这里设置的密码配合使用，因此需要牢记此密码.

6. 生成供Java使用的公钥rsa_public_key.pem

openssl rsa -in private_key.pem -out rsa_public_key.pem -pubout

7. 生成供Java使用的私钥pkcs8_private_key.pem

openssl pkcs8 -topk8 -in private_key.pem -out pkcs8_private_key.pem -nocrypt

全部执行成功后，会生成如下文件，其中public_key.der和private_key.p12就是iOS需要用到的文件，如下图：

生成的文件

二、将文件导入工程使用

1.新建工程, 并导入Security.framework框架, 如下图:

新建工程并添加框架

2.导入秘钥文件

导入.der和.p12格式的秘钥文件, 如下图:

导入秘钥文件

3.新建用于加密、解密的类RSAEncryptor, 并实现相关方法

新建RSAEncryptor类, 如下图:

新建用于加密解密的类

下面开始上代码, 可以直接复制过去用:

RSAEncryptor.h代码如下:

#import 
    
     @interface RSAEncryptor : NSObject/** *  加密方法 * *  @param str   需要加密的字符串 *  @param path  '.der'格式的公钥文件路径 */+ (NSString *)encryptString:(NSString *)str publicKeyWithContentsOfFile:(NSString *)path;/** *  解密方法 * *  @param str       需要解密的字符串 *  @param path      '.p12'格式的私钥文件路径 *  @param password  私钥文件密码 */+ (NSString *)decryptString:(NSString *)str privateKeyWithContentsOfFile:(NSString *)path password:(NSString *)password;/** *  加密方法 * *  @param str    需要加密的字符串 *  @param pubKey 公钥字符串 */+ (NSString *)encryptString:(NSString *)str publicKey:(NSString *)pubKey;/** *  解密方法 * *  @param str     需要解密的字符串 *  @param privKey 私钥字符串 */+ (NSString *)decryptString:(NSString *)str privateKey:(NSString *)privKey;@end

RSAEncryptor.m代码如下:

#import "RSAEncryptor.h"#import 
    
     @implementation RSAEncryptorstatic NSString *base64_encode_data(NSData *data){    data = [data base64EncodedDataWithOptions:0];    NSString *ret = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];    return ret;}static NSData *base64_decode(NSString *str){    NSData *data = [[NSData alloc] initWithBase64EncodedString:str options:NSDataBase64DecodingIgnoreUnknownCharacters];    return data;}#pragma mark - 使用'.der'公钥文件加密//加密+ (NSString *)encryptString:(NSString *)str publicKeyWithContentsOfFile:(NSString *)path{    if (!str || !path)  return nil;    return [self encryptString:str publicKeyRef:[self getPublicKeyRefWithContentsOfFile:path]];}//获取公钥+ (SecKeyRef)getPublicKeyRefWithContentsOfFile:(NSString *)filePath{    NSData *certData = [NSData dataWithContentsOfFile:filePath];    if (!certData) {        return nil;    }    SecCertificateRef cert = SecCertificateCreateWithData(NULL, (CFDataRef)certData);    SecKeyRef key = NULL;    SecTrustRef trust = NULL;    SecPolicyRef policy = NULL;    if (cert != NULL) {        policy = SecPolicyCreateBasicX509();        if (policy) {            if (SecTrustCreateWithCertificates((CFTypeRef)cert, policy, &trust) == noErr) {                SecTrustResultType result;                if (SecTrustEvaluate(trust, &result) == noErr) {                    key = SecTrustCopyPublicKey(trust);                }            }        }    }    if (policy) CFRelease(policy);    if (trust) CFRelease(trust);    if (cert) CFRelease(cert);    return key;}+ (NSString *)encryptString:(NSString *)str publicKeyRef:(SecKeyRef)publicKeyRef{    if(![str dataUsingEncoding:NSUTF8StringEncoding]){        return nil;    }    if(!publicKeyRef){        return nil;    }    NSData *data = [self encryptData:[str dataUsingEncoding:NSUTF8StringEncoding] withKeyRef:publicKeyRef];    NSString *ret = base64_encode_data(data);    return ret;}#pragma mark - 使用'.12'私钥文件解密//解密+ (NSString *)decryptString:(NSString *)str privateKeyWithContentsOfFile:(NSString *)path password:(NSString *)password{    if (!str || !path) return nil;    if (!password) password = @"";    return [self decryptString:str privateKeyRef:[self getPrivateKeyRefWithContentsOfFile:path password:password]];}//获取私钥+ (SecKeyRef)getPrivateKeyRefWithContentsOfFile:(NSString *)filePath password:(NSString*)password{    NSData *p12Data = [NSData dataWithContentsOfFile:filePath];    if (!p12Data) {        return nil;    }    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;}+ (NSString *)decryptString:(NSString *)str privateKeyRef:(SecKeyRef)privKeyRef{    NSData *data = [[NSData alloc] initWithBase64EncodedString:str options:NSDataBase64DecodingIgnoreUnknownCharacters];    if (!privKeyRef) {        return nil;    }    data = [self decryptData:data withKeyRef:privKeyRef];    NSString *ret = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];    return ret;}#pragma mark - 使用公钥字符串加密/* START: Encryption with RSA public key *///使用公钥字符串加密+ (NSString *)encryptString:(NSString *)str publicKey:(NSString *)pubKey{    NSData *data = [self encryptData:[str dataUsingEncoding:NSUTF8StringEncoding] publicKey:pubKey];    NSString *ret = base64_encode_data(data);    return ret;}+ (NSData *)encryptData:(NSData *)data publicKey:(NSString *)pubKey{    if(!data || !pubKey){        return nil;    }    SecKeyRef keyRef = [self addPublicKey:pubKey];    if(!keyRef){        return nil;    }    return [self encryptData:data withKeyRef:keyRef];}+ (SecKeyRef)addPublicKey:(NSString *)key{    NSRange spos = [key rangeOfString:@"-----BEGIN PUBLIC KEY-----"];    NSRange epos = [key rangeOfString:@"-----END PUBLIC KEY-----"];    if(spos.location != NSNotFound && epos.location != NSNotFound){        NSUInteger s = spos.location + spos.length;        NSUInteger e = epos.location;        NSRange range = NSMakeRange(s, e-s);        key = [key substringWithRange:range];    }    key = [key stringByReplacingOccurrencesOfString:@"\r" withString:@""];    key = [key stringByReplacingOccurrencesOfString:@"\n" withString:@""];    key = [key stringByReplacingOccurrencesOfString:@"\t" withString:@""];    key = [key stringByReplacingOccurrencesOfString:@" "  withString:@""];    // This will be base64 encoded, decode it.    NSData *data = base64_decode(key);    data = [self stripPublicKeyHeader:data];    if(!data){        return nil;    }    //a tag to read/write keychain storage    NSString *tag = @"RSAUtil_PubKey";    NSData *d_tag = [NSData dataWithBytes:[tag UTF8String] length:[tag length]];    // Delete any old lingering key with the same tag    NSMutableDictionary *publicKey = [[NSMutableDictionary alloc] init];    [publicKey setObject:(__bridge id) kSecClassKey forKey:(__bridge id)kSecClass];    [publicKey setObject:(__bridge id) kSecAttrKeyTypeRSA forKey:(__bridge id)kSecAttrKeyType];    [publicKey setObject:d_tag forKey:(__bridge id)kSecAttrApplicationTag];    SecItemDelete((__bridge CFDictionaryRef)publicKey);    // Add persistent version of the key to system keychain    [publicKey setObject:data forKey:(__bridge id)kSecValueData];    [publicKey setObject:(__bridge id) kSecAttrKeyClassPublic forKey:(__bridge id)     kSecAttrKeyClass];    [publicKey setObject:[NSNumber numberWithBool:YES] forKey:(__bridge id)     kSecReturnPersistentRef];    CFTypeRef persistKey = nil;    OSStatus status = SecItemAdd((__bridge CFDictionaryRef)publicKey, &persistKey);    if (persistKey != nil){        CFRelease(persistKey);    }    if ((status != noErr) && (status != errSecDuplicateItem)) {        return nil;    }    [publicKey removeObjectForKey:(__bridge id)kSecValueData];    [publicKey removeObjectForKey:(__bridge id)kSecReturnPersistentRef];    [publicKey setObject:[NSNumber numberWithBool:YES] forKey:(__bridge id)kSecReturnRef];    [publicKey setObject:(__bridge id) kSecAttrKeyTypeRSA forKey:(__bridge id)kSecAttrKeyType];    // Now fetch the SecKeyRef version of the key    SecKeyRef keyRef = nil;    status = SecItemCopyMatching((__bridge CFDictionaryRef)publicKey, (CFTypeRef *)&keyRef);    if(status != noErr){        return nil;    }    return keyRef;}+ (NSData *)stripPublicKeyHeader:(NSData *)d_key{    // Skip ASN.1 public key header    if (d_key == nil) return(nil);    unsigned long len = [d_key length];    if (!len) return(nil);    unsigned char *c_key = (unsigned char *)[d_key bytes];    unsigned int  idx     = 0;    if (c_key[idx++] != 0x30) return(nil);    if (c_key[idx] > 0x80) idx += c_key[idx] - 0x80 + 1;    else idx++;    // PKCS #1 rsaEncryption szOID_RSA_RSA    static unsigned char seqiod[] =    { 0x30,   0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01,        0x01, 0x05, 0x00 };    if (memcmp(&c_key[idx], seqiod, 15)) return(nil);    idx += 15;    if (c_key[idx++] != 0x03) return(nil);    if (c_key[idx] > 0x80) idx += c_key[idx] - 0x80 + 1;    else idx++;    if (c_key[idx++] != '\0') return(nil);    // Now make a new NSData from this buffer    return ([NSData dataWithBytes:&c_key[idx] length:len - idx]);}+ (NSData *)encryptData:(NSData *)data withKeyRef:(SecKeyRef) keyRef{    const uint8_t *srcbuf = (const uint8_t *)[data bytes];    size_t srclen = (size_t)data.length;    size_t block_size = SecKeyGetBlockSize(keyRef) * sizeof(uint8_t);    void *outbuf = malloc(block_size);    size_t src_block_size = block_size - 11;    NSMutableData *ret = [[NSMutableData alloc] init];    for(int idx=0; idx
     
       src_block_size){            data_len = src_block_size;        }        size_t outlen = block_size;        OSStatus status = noErr;        status = SecKeyEncrypt(keyRef,                               kSecPaddingPKCS1,                               srcbuf + idx,                               data_len,                               outbuf,                               &outlen                               );        if (status != 0) {            NSLog(@"SecKeyEncrypt fail. Error Code: %d", status);            ret = nil;            break;        }else{            [ret appendBytes:outbuf length:outlen];        }    }    free(outbuf);    CFRelease(keyRef);    return ret;}/* END: Encryption with RSA public key */#pragma mark - 使用私钥字符串解密/* START: Decryption with RSA private key *///使用私钥字符串解密+ (NSString *)decryptString:(NSString *)str privateKey:(NSString *)privKey{    if (!str) return nil;    NSData *data = [[NSData alloc] initWithBase64EncodedString:str options:NSDataBase64DecodingIgnoreUnknownCharacters];    data = [self decryptData:data privateKey:privKey];    NSString *ret = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];    return ret;}+ (NSData *)decryptData:(NSData *)data privateKey:(NSString *)privKey{    if(!data || !privKey){        return nil;    }    SecKeyRef keyRef = [self addPrivateKey:privKey];    if(!keyRef){        return nil;    }    return [self decryptData:data withKeyRef:keyRef];}+ (SecKeyRef)addPrivateKey:(NSString *)key{    NSRange spos = [key rangeOfString:@"-----BEGIN RSA PRIVATE KEY-----"];    NSRange epos = [key rangeOfString:@"-----END RSA PRIVATE KEY-----"];    if(spos.location != NSNotFound && epos.location != NSNotFound){        NSUInteger s = spos.location + spos.length;        NSUInteger e = epos.location;        NSRange range = NSMakeRange(s, e-s);        key = [key substringWithRange:range];    }    key = [key stringByReplacingOccurrencesOfString:@"\r" withString:@""];    key = [key stringByReplacingOccurrencesOfString:@"\n" withString:@""];    key = [key stringByReplacingOccurrencesOfString:@"\t" withString:@""];    key = [key stringByReplacingOccurrencesOfString:@" "  withString:@""];    // This will be base64 encoded, decode it.    NSData *data = base64_decode(key);    data = [self stripPrivateKeyHeader:data];    if(!data){        return nil;    }    //a tag to read/write keychain storage    NSString *tag = @"RSAUtil_PrivKey";    NSData *d_tag = [NSData dataWithBytes:[tag UTF8String] length:[tag length]];    // Delete any old lingering key with the same tag    NSMutableDictionary *privateKey = [[NSMutableDictionary alloc] init];    [privateKey setObject:(__bridge id) kSecClassKey forKey:(__bridge id)kSecClass];    [privateKey setObject:(__bridge id) kSecAttrKeyTypeRSA forKey:(__bridge id)kSecAttrKeyType];    [privateKey setObject:d_tag forKey:(__bridge id)kSecAttrApplicationTag];    SecItemDelete((__bridge CFDictionaryRef)privateKey);    // Add persistent version of the key to system keychain    [privateKey setObject:data forKey:(__bridge id)kSecValueData];    [privateKey setObject:(__bridge id) kSecAttrKeyClassPrivate forKey:(__bridge id)     kSecAttrKeyClass];    [privateKey setObject:[NSNumber numberWithBool:YES] forKey:(__bridge id)     kSecReturnPersistentRef];    CFTypeRef persistKey = nil;    OSStatus status = SecItemAdd((__bridge CFDictionaryRef)privateKey, &persistKey);    if (persistKey != nil){        CFRelease(persistKey);    }    if ((status != noErr) && (status != errSecDuplicateItem)) {        return nil;    }    [privateKey removeObjectForKey:(__bridge id)kSecValueData];    [privateKey removeObjectForKey:(__bridge id)kSecReturnPersistentRef];    [privateKey setObject:[NSNumber numberWithBool:YES] forKey:(__bridge id)kSecReturnRef];    [privateKey setObject:(__bridge id) kSecAttrKeyTypeRSA forKey:(__bridge id)kSecAttrKeyType];    // Now fetch the SecKeyRef version of the key    SecKeyRef keyRef = nil;    status = SecItemCopyMatching((__bridge CFDictionaryRef)privateKey, (CFTypeRef *)&keyRef);    if(status != noErr){        return nil;    }    return keyRef;}+ (NSData *)stripPrivateKeyHeader:(NSData *)d_key{    // Skip ASN.1 private key header    if (d_key == nil) return(nil);    unsigned long len = [d_key length];    if (!len) return(nil);    unsigned char *c_key = (unsigned char *)[d_key bytes];    unsigned int  idx     = 22; //magic byte at offset 22    if (0x04 != c_key[idx++]) return nil;    //calculate length of the key    unsigned int c_len = c_key[idx++];    int det = c_len & 0x80;    if (!det) {        c_len = c_len & 0x7f;    } else {        int byteCount = c_len & 0x7f;        if (byteCount + idx > len) {            //rsa length field longer than buffer            return nil;        }        unsigned int accum = 0;        unsigned char *ptr = &c_key[idx];        idx += byteCount;        while (byteCount) {            accum = (accum << 8) + *ptr;            ptr++;            byteCount--;        }        c_len = accum;    }    // Now make a new NSData from this buffer    return [d_key subdataWithRange:NSMakeRange(idx, c_len)];}+ (NSData *)decryptData:(NSData *)data withKeyRef:(SecKeyRef) keyRef{    const uint8_t *srcbuf = (const uint8_t *)[data bytes];    size_t srclen = (size_t)data.length;    size_t block_size = SecKeyGetBlockSize(keyRef) * sizeof(uint8_t);    UInt8 *outbuf = malloc(block_size);    size_t src_block_size = block_size;    NSMutableData *ret = [[NSMutableData alloc] init];    for(int idx=0; idx
      
        src_block_size){            data_len = src_block_size;        }        size_t outlen = block_size;        OSStatus status = noErr;        status = SecKeyDecrypt(keyRef,                               kSecPaddingNone,                               srcbuf + idx,                               data_len,                               outbuf,                               &outlen                               );        if (status != 0) {            NSLog(@"SecKeyEncrypt fail. Error Code: %d", status);            ret = nil;            break;        }else{            //the actual decrypted data is in the middle, locate it!            int idxFirstZero = -1;            int idxNextZero = (int)outlen;            for ( int i = 0; i < outlen; i++ ) {                if ( outbuf[i] == 0 ) {                    if ( idxFirstZero < 0 ) {                        idxFirstZero = i;                    } else {                        idxNextZero = i;                        break;                    }                }            }            [ret appendBytes:&outbuf[idxFirstZero+1] length:idxNextZero-idxFirstZero-1];        }    }    free(outbuf);    CFRelease(keyRef);    return ret;}/* END: Decryption with RSA private key */@end

4. 测试加密、解密

首先先测试使用.der和.p12秘钥文件进行加密、解密, 在ViewController.m中进行测试, 代码如下:

#import "ViewController.h"#import "RSAEncryptor.h"@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    //原始数据    NSString *originalString = @"这是一段将要使用'.der'文件加密的字符串!";    //使用.der和.p12中的公钥私钥加密解密    NSString *public_key_path = [[NSBundle mainBundle] pathForResource:@"public_key.der" ofType:nil];    NSString *private_key_path = [[NSBundle mainBundle] pathForResource:@"private_key.p12" ofType:nil];    NSString *encryptStr = [RSAEncryptor encryptString:originalString publicKeyWithContentsOfFile:public_key_path];    NSLog(@"加密前:%@", originalString);    NSLog(@"加密后:%@", encryptStr);    NSLog(@"解密后:%@", [RSAEncryptor decryptString:encryptStr privateKeyWithContentsOfFile:private_key_path password:@"123456"]);}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}@end

运行后, 输出信息如下:

输出结果

可以看到已经可以成功加密、解密了.

下面接着测试使用秘钥字符串进行加密、解密, 那么秘钥字符串从哪里来? 可以来这里:, 这是一个在线生成RSA秘钥的网站, 生成公钥和秘钥后, 复制出来用于测试. 然后在ViewController.m中使用RSAEntryptor.h头文件中对应的加密方法进行加密,ViewController.m中代码如下:

#import "ViewController.h"#import "RSAEncryptor.h"@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    //原始数据    NSString *originalString = @"这是一段将要使用'秘钥字符串'进行加密的字符串!";    //使用字符串格式的公钥私钥加密解密    NSString *encryptStr = [RSAEncryptor encryptString:originalString publicKey:@"MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDTbZ6cNH9PgdF60aQKveLz3FTalyzHQwbp601y77SzmGHX3F5NoVUZbdK7UMdoCLK4FBziTewYD9DWvAErXZo9BFuI96bAop8wfl1VkZyyHTcznxNJFGSQd/B70/ExMgMBpEwkAAdyUqIjIdVGh1FQK/4acwS39YXwbS+IlHsPSQIDAQAB"];    NSLog(@"加密前:%@", originalString);    NSLog(@"加密后:%@", encryptStr);    NSLog(@"解密后:%@", [RSAEncryptor decryptString:encryptStr privateKey:@"MIICeAIBADANBgkqhkiG9w0BAQEFAASCAmIwggJeAgEAAoGBANNtnpw0f0+B0XrRpAq94vPcVNqXLMdDBunrTXLvtLOYYdfcXk2hVRlt0rtQx2gIsrgUHOJN7BgP0Na8AStdmj0EW4j3psCinzB+XVWRnLIdNzOfE0kUZJB38HvT8TEyAwGkTCQAB3JSoiMh1UaHUVAr/hpzBLf1hfBtL4iUew9JAgMBAAECgYA1tGeQmAkqofga8XtwuxEWDoaDS9k0+EKeUoXGxzqoT/GyiihuIafjILFhoUA1ndf/yCQaG973sbTDhtfpMwqFNQq13+JAownslTjWgr7Hwf7qplYW92R7CU0v7wFfjqm1t/2FKU9JkHfaHfb7qqESMIbO/VMjER9o4tEx58uXDQJBAO0O4lnWDVjr1gN02cqvxPOtTY6DgFbQDeaAZF8obb6XqvCqGW/AVms3Bh8nVlUwdQ2K/xte8tHxjW9FtBQTLd8CQQDkUncO35gAqUF9Bhsdzrs7nO1J3VjLrM0ITrepqjqtVEvdXZc+1/UrkWVaIigWAXjQCVfmQzScdbznhYXPz5fXAkEAgB3KMRkhL4yNpmKRjhw+ih+ASeRCCSj6Sjfbhx4XaakYZmbXxnChg+JB+bZNz06YBFC5nLZM7y/n61o1f5/56wJBALw+ZVzE6ly5L34114uG04W9x0HcFgau7MiJphFjgUdAtd/H9xfgE4odMRPUD3q9Me9LlMYK6MiKpfm4c2+3dzcCQQC8y37NPgpNEkd9smMwPpSEjPW41aMlfcKvP4Da3z7G5bGlmuICrva9YDAiaAyDGGCK8LxC8K6HpKrFgYrXkRtt"]);}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}@end

运行后, 输出信息如下: