29
CFRelease(trust);
30
}
31
}
32
}
33
}
34
}
35
}
36
return
status;
37
}
5. 用公钥对数据加密。
38
//加密
39
- (NSMutableData *)encryptWithPublicKey:(NSData *)plainData {
40
// 分配内存块，用于存放加密后的数据段
41
size_t
cipherBufferSize = SecKeyGetBlockSize(_publicKey);
42
uint8_t *cipherBuffer = malloc(cipherBufferSize *
sizeof
(uint8_t));
43
double
totalLength = [plainData length];
44
size_t
blockSize = cipherBufferSize - 12;
45
size_t
blockCount = (
size_t
)ceil(totalLength / blockSize);
46
NSMutableData *encryptedData = [NSMutableData data];
47
// 分段加密
48
for
(
int
i = 0; i < blockCount; i++) {
49
NSUInteger loc = i * blockSize;
50
// 数据段的实际大小。最后一段可能比 blockSize 小。
51
int
dataSegmentRealSize = MIN(blockSize, [plainData length] - loc);
52
// 截取需要加密的数据段
53
NSData *dataSegment = [plainData subdataWithRange:NSMakeRange(loc,
dataSegmentRealSize)];
54
OSStatus status = SecKeyEncrypt(_publicKey, kSecPaddingPKCS1, (
const
uint8_t
*)[dataSegment bytes], dataSegmentRealSize, cipherBuffer, &cipherBufferSize);
55
if
(status == errSecSuccess) {
56
NSData *encryptedDataSegment = [[NSData alloc] initWithBytes:(
const
void
*)cipherBuffer length:cipherBufferSize];
57
// 追加加密后的数据段
58
[encryptedData appendData:encryptedDataSegment];
59
[encryptedDataSegment release];
60
}
else
{
61
if
(cipherBuffer) {
62
free(cipherBuffer);
63
}