songxing10000/RSAEncryptor.m

## RSAEncryptor.m
#import "RSAEncryptor.h"
#import <Security/Security.h>
@implementation RSAEncryptor

static 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{
    NSLog(@"%@",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{
    NSLog(@"%@",pubKey);
    NSData *data = [self encryptData:[str dataUsingEncoding:NSUTF8StringEncoding] publicKey:pubKey];

    NSLog(@"%@",data);

    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<srclen; idx+=src_block_size){
        //NSLog(@"%d/%d block_size: %d", idx, (int)srclen, (int)block_size);
        size_t data_len = srclen - idx;
        if(data_len > 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", (int)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<srclen; idx+=src_block_size){
        //NSLog(@"%d/%d block_size: %d", idx, (int)srclen, (int)block_size);
        size_t data_len = srclen - idx;
        if(data_len > 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", (int)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
	#import "RSAEncryptor.h"
	#import <Security/Security.h>
	@implementation RSAEncryptor

	static 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{
	NSLog(@"%@",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{
	NSLog(@"%@",pubKey);
	NSData *data = [self encryptData:[str dataUsingEncoding:NSUTF8StringEncoding] publicKey:pubKey];

	NSLog(@"%@",data);

	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<srclen; idx+=src_block_size){
	//NSLog(@"%d/%d block_size: %d", idx, (int)srclen, (int)block_size);
	size_t data_len = srclen - idx;
	if(data_len > 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", (int)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<srclen; idx+=src_block_size){
	//NSLog(@"%d/%d block_size: %d", idx, (int)srclen, (int)block_size);
	size_t data_len = srclen - idx;
	if(data_len > 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", (int)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