iOS Sqlite加密(FMDB/SQLCipher)

/**
*  对数据库加密
*
*  @param path path description
*
*  @return return value description
*/
+ (BOOL)encryptDatabase:(NSString *)path;

/**
*  对数据库解密
*
*  @param path path description
*
*  @return return value description
*/
+ (BOOL)unEncryptDatabase:(NSString *)path;

/**
*  修改数据库秘钥
*
*  @param dbPath    dbPath description
*  @param originKey originKey description
*  @param newKey    newKey description
*
*  @return return value description
*/
+ (BOOL)changeKey:(NSString *)dbPath originKey:(NSString *)originKey newKey:(NSString *)newKey;

+ (BOOL)encryptDatabase:(NSString *)path {
NSString *sourcePath = path;
NSString *targetPath = [NSString stringWithFormat:@"%@.tmp.db", path];

if([self encryptDatabase:sourcePath targetPath:targetPath]) {
NSFileManager *fm = [[NSFileManager alloc] init];
[fm removeItemAtPath:sourcePath error:nil];
[fm moveItemAtPath:targetPath toPath:sourcePath error:nil];
return YES;
} else {
return NO;
}
}

+ (BOOL)unEncryptDatabase:(NSString *)path {
NSString *sourcePath = path;
NSString *targetPath = [NSString stringWithFormat:@"%@.tmp.db", path];

if([self unEncryptDatabase:sourcePath targetPath:targetPath]) {
NSFileManager *fm = [[NSFileManager alloc] init];
[fm removeItemAtPath:sourcePath error:nil];
[fm moveItemAtPath:targetPath toPath:sourcePath error:nil];
return YES;
} else {
return NO;
}
}

+ (BOOL)encryptDatabase:(NSString *)sourcePath targetPath:(NSString *)targetPath {
const char* sqlQ = [[NSString stringWithFormat:@"ATTACH DATABASE '%@' AS encrypted KEY '%@';", targetPath, kEncryptKey] UTF8String];

sqlite3 *unencrypted_DB;
if (sqlite3_open([sourcePath UTF8String], &unencrypted_DB) == SQLITE_OK) {

// Attach empty encrypted database to unencrypted database
sqlite3_exec(unencrypted_DB, sqlQ, NULL, NULL, NULL);

// export database
sqlite3_exec(unencrypted_DB, "SELECT sqlcipher_export('encrypted');", NULL, NULL, NULL);

// Detach encrypted database
sqlite3_exec(unencrypted_DB, "DETACH DATABASE encrypted;", NULL, NULL, NULL);

sqlite3_close(unencrypted_DB);

return YES;
}
else {
sqlite3_close(unencrypted_DB);
NSAssert1(NO, @"Failed to open database with message '%s'.", sqlite3_errmsg(unencrypted_DB));

return NO;
}
}

+ (BOOL)unEncryptDatabase:(NSString *)sourcePath targetPath:(NSString *)targetPath {
const char* sqlQ = [[NSString stringWithFormat:@"ATTACH DATABASE '%@' AS plaintext KEY '';", targetPath] UTF8String];

sqlite3 *encrypted_DB;
if (sqlite3_open([sourcePath UTF8String], &encrypted_DB) == SQLITE_OK) {

sqlite3_exec(encrypted_DB, [[NSString stringWithFormat:@"PRAGMA key = '%@';", kEncryptKey] UTF8String], NULL, NULL, NULL);

// Attach empty unencrypted database to encrypted database
sqlite3_exec(encrypted_DB, sqlQ, NULL, NULL, NULL);

// export database
sqlite3_exec(encrypted_DB, "SELECT sqlcipher_export('plaintext');", NULL, NULL, NULL);

// Detach unencrypted database
sqlite3_exec(encrypted_DB, "DETACH DATABASE plaintext;", NULL, NULL, NULL);

sqlite3_close(encrypted_DB);

return YES;
}
else {
sqlite3_close(encrypted_DB);
NSAssert1(NO, @"Failed to open database with message '%s'.", sqlite3_errmsg(encrypted_DB));

return NO;
}
}

+ (BOOL)changeKey:(NSString *)dbPath originKey:(NSString *)originKey newKey:(NSString *)newKey {
sqlite3 *encrypted_DB;
if (sqlite3_open([dbPath UTF8String], &encrypted_DB) == SQLITE_OK) {

sqlite3_exec(encrypted_DB, [[NSString stringWithFormat:@"PRAGMA key = '%@';", originKey] UTF8String], NULL, NULL, NULL);

sqlite3_exec(encrypted_DB, [[NSString stringWithFormat:@"PRAGMA rekey = '%@';", newKey] UTF8String], NULL, NULL, NULL);

sqlite3_close(encrypted_DB);
return YES;
}
else {
sqlite3_close(encrypted_DB);
NSAssert1(NO, @"Failed to open database with message '%s'.", sqlite3_errmsg(encrypted_DB));

return NO;
}
}