Mifare key a key b Here’s how it works: Imagine you have a card and a reader (like a door lock and a key). I tried to reproduce it on an old official tag (at least I hope it is official). With MIFARE 1K and 4K cards, access to a sector’s data may require one or two authentication keys. 3: 2963: May 5, 2021 RFID change default key. 3,629 5 5 MIFARE DESFire Keys issue. The access control blocks contain Key A, Key B, and the Access Bits. This is not a new topic, but rather my own vision of the many different things that’ve been done concerning RFID. They can be used with time attending systems, electronic door locks, vending machines and other devices which support this standard. Any help would be greatly appreciated. Reading the tag UID of Mifare classic card. 3 FEIG readers require Le='04' to automatically switch to Mifare if the card supports both T=CL and In order to change the access keys of a sector on a MIFARE Classic card, you simply have to update that sector's trailer block. When Authentication is complete then you can read or write. Found Mifare Classic Mini tag ISO/IEC 14443A (106 kbps) target: ATQA (SENS_RES): 00 04 * UID size: single * bit frame anticollision supported UID (NFCID1): ee 6a 7e 50 SAK (SEL_RES): 09 * Not compliant with ISO/IEC 14443-4 * Not compliant with ISO/IEC 18092 Fingerprinting based on MIFARE type Identification Procedure: * MIFARE Mini 0. There is a different byte code that it is sent to the device and stores the key for that sector, using the 0x61 and 0x60 code for Key b and Key A, for the sector. For my parking card I computed the key B with an external USB reader and Linux. I understand that unless I get a special Chinese card, I can't change the UID. The main thing you are missing is specifying the dictionary of keys to use when running the key How does Key B work with Key A the to decrypt MIFARE 1k data excately? Related topics Topic Replies Views Activity; Key Change read / write RFID-RC522. . medium. A pop-up is displayed asking you to place the key on the encoder. MIFARE SAM. The last block in the sector (3 in this example) holds the keys and Based on some experimenting, I believe the 1st key is skipped for one of two reasons: If you follow the code flow, in loop(), PICC_IsNewCardPresent() and PICC_ReadCardSerial() called. Mifare authentication. For the former the reader translates a pseudo-APDU to the respective command, therefore the reader or its driver may require different bytes. They can also be used for payment and loyalty programs, event ticketing, and identification purposes. The MIFARE Classic 1K offers 1024 bytes of data storage, split into 16 sectors; each sector is protected by two different keys, called A and B. 1. But unable to read/write using it. It shows access bits as FF078000 and Key B is 222222222222 Now I am using Key B to read the data from the mifare classic (I have verified this with other apps so I know for certain that the card is a Mifare Classic and that my key is correct. However, even though I know the key is correct (it works with other apps like Mifare Classic Tool and my previous Java app), my React Native implementation consistently fails to authenticate. Read-key A 2. Click Read SAM card. 6) 1. Skip to content. Sorry for my bad englease. Else you can write the access conditions here. Each sector of a MIFARE Classic card has two authentication keys: key A and key B. UID: e4b8167f Key A: 00c4356eb900 Key B: 00d62929d600. The 4kByte EEPROM memory is organized in 32 sectors with 4 blocks and in 8 sectors with 16 blocks. Many cards are still in the wild with these. In the Memory panel, select the Get other sectors if unable to get selected checkbox if To put it simply, Mfkey32v2 is a tool that helps to generate a Mifare Classic Card’s sector keys. Small Arduino Program to crack by brute force a sector key of a MIRAFE/RFID tag. See (Figure 1. Installation Guide. https://meminoglu. MIFARE Classic 1K load b) If a single key is provided, each sector will be checked for this key and if valid, add it to the list of known keys for that particular sector. 00. Table 6. Sensors. Set 78 77 88 FF if you want key A for reading only and key B for writing and reading. Messing it up will lock sector etc. RunAsync("ReadNdef", "getNdefMessage", Null, 0) The Null part is simply described as "Params - Array of parameters". The MIFARE Classic 1K technology allows for read and write capabilities, making it ideal for Mifare Change KEY A and B. I want to write data in to mifare card. Download Datasheet. Improve this answer. Data is encrypted using a 48-bit key and stored in sectors on the key fob. NOTE: These hardware changes resulted in the Proxmark 3 Easy being incapable of performing several of the Proxmark's advanced features, including the Mifare Hard-Nested attacks. What I’ve Tried Here is my implementation for sector 0 Industry Standard MIFARE® Card (14443 Type A/B), S70. L. It is intended, that Key B can have higher rights than Key A. The reader sends out what we call “nonces” – these are like secret codes. 4. Currently my dictionary has 3520 keys that don't work on my card. Key Features; Specifications; Applications > IC card ( Mifare card) with frequency 13. g. Each key can be programmed to allow operations such as reading, writing, increasing valueblocks, etc. Now I need to restore those key. MIFARE Classic 4K offers 4096 bytes split into forty sectors, of which 32 are keytype - must be either Mifare. Than I used wrlb command to change this block. KEY_A or Mifare. Gallagher taken from your trace: mfkey64. 2 Access conditions for the sector trailer [] On chip delivery the access conditions for the sector trailers and key A are predefined as transport Full encryption with all different Key A and Key B creates a tight security to Mifare 1K card. only_Cryptanalysis_on_Hardened_Mifare_Classic_Cards-CCS_2015. As we start this series, you won’t find anything that hasn’t already been discussed before. mfrc522. How to do that using proxmark ? Also I'm trying to copy one card. Like most remote key fobs, you will need to have a proximity reader, either the SK9000I or SK9001I Comelit SimpleKey readers. When key B is readable i got: authentication with key B works (expected), the write command went through (unexpected), the data was NOT written (expected). First 6 byte (12 hex character) is key a and last 6 byte (12 hex character again) is key b. 1. hf mf hard * A a0a1a2a3a4a5 4 A [EN] This tool provides several features to interact with MIFARE Classic RFID-Tags with ACR122U tag reader. our issue will be solved By changing the Key Access Bit conditions. The main thing you are missing is specifying the dictionary of keys to use when running the key 13. Place the appropriate SAM card on the encoder when the LED light begins to flash. Example: To read from block 10, first authenticate using a key from sector 3 (blocks 8-11). Mifare Ultralight C Authentication in Android (2. - Electroner/MIFARE-Sector-Key-Cracker. First of all, you need the keys for the tag you want to read. This is a quirky FS and we need to stick together if we want to avoid headaches! Describe the bug hf mf autopwn failed to dump with key B: [=] fast dump reported back failure w KEY B [=] Dump file is PARTIAL complete hf mf dump works well. Mifare Classic 1k write keys. HID | MIFARE Classic Key [usb] pm3 --> hf mf autopwn [=] MIFARE Classic EV1 card detected [=] target sector 17 key type B -- using valid key [ 4B791BEA7BCC ] (used for nested / hardnested attack) [+] loaded 56 keys from hardcoded default array [=] running strategy 1 [=] Chunk 1,5s | found 34/36 keys (56) [=] running strategy 2 [=] Chunk 1,3s | found 34/36 keys (56) [+] target sector 0 Mifare and smart cards are different, only the latter understand APDUs. with Taginfo) you cannot read the contents of the sectors or even First of all, you need the keys for the tag you want to read. The built in dictionary is intentionally designed to only MIFARE provides NFC-enabled contactless solutions in multiple form factors for a range of applications, including smart car access and smart cards. So for example, one person can have the B key, and can write and read data blocks from the card, but can't change neither the A or B key, or access codes. 0x4 : 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 Authenticated block nb. Colour: Black, Blue, Green, Orange, Red. keys and extended-std. However, when i take card dump, i get access to Sector 15 but A Key is missing. Proxmark method. I have identified the key that is used to read/write the mifare card using NXP Taginfo and Mifare Classic Tool. Use "NFC TagInfo" application for android. Sector 0 will have 4 blocks (0,1,2 and 3). Improve this Proxmark3 RDV4 Verification and testing for default keys. MIFARE SAM offers secure storage and communication for a so i am continuing to launch these commands everytime increasing by 4 the block number : hf mf hard * A a0a1a2a3a4a5 0 A. MIFARE_SetKeys(oldkeya, oldkeyb, newkeya, newkeyb, sector); I'm looking to change keys but I can't find this function in the library - or anywhere. How to change the Mifare Classic 1k key A and Key B. For KeyA Based Authentication ,Read and Write Operation which getting success. 7. 0 out of 5 stars 12 2 offers from ₹12,07744 ₹ 12,077 44 Mifare Classic is broken into sectors. Contribute to hootan09/rfidCrack development by creating an account on GitHub. So, for instance, if your current key B is FFFFFFFFFFFF (and the current access conditions permit writing of the sector trailer with key B), you would first authenticate for that sector with that current key B. If additional applications join the same MIFARE card key B may be forwarded to the organization which provides the new services in order to enable directory (MAD) adaptation during re-initialization of the MIFARE cards. Frequency: 13. Authentication fails when trying to override the data ina specific block. 56 MHz key fobs that Key B is readable but still can be used for authentication and writing. - MIFARE-Sector-Key-Cracker/Cracker only Serial. All A subreddit dedicated to the discussion, usage, and maintenance of the BTRFS filesystem. Read/Write distance: 0 - 3cm. These have the same key A and key B for all sectors. Follow answered Aug 24, 2015 at 10:56. Due to some weaknesses in MIFARE Classic, you can retrieve all the keys (A and B) of a tag with tools like the Proxmark3 or normal RFID-Readers and some special software (mfcuk, mfoc). 3. Hot Network Questions Suspension spectrum functor 2010s-era Analog story referring to something like the "bouba/kiki" effect The Mifare Classic specification from NXP explicitly states, that data should not be readable using KeyB when using transport configuration (factory default), because KeyB is readable (having KeyA) by itself. Our New All Mifare keys have a MAD, which is the directory of the key, and contains data about the properties of the key sectors. It is based on fact, that decryption and encryption using symmetric ciphers like DES, 3DES or AES are inverse functions, which can be both used both Changing authentication key of a sector in MIFARE Classic. I have a mifare classic 1K card and custom Key. Size: 40mm x 32mm x 4. masterix Contributor Hi dears, today i found two Mifare 4K cards used with an access control reader. SKU: 1434MSSNN. 6 Write-key B Key B of sector 0 is programmed by the card issuer and should be kept secret. Since the card/tag is not "new", PICC_IsNewCardPresent() MIFARE® DESFire® EV2 8K key fobs are Honeywell credentials and are compatible with LuminAXS, and Omni®Arch readers. Need help to find my mistake. After installing all the software/drivers and flashing the Proxmark with the latest firmware (), all of which was quite straightforward Comelit SK9050B/A Simplekey Standard Key Fob - Blue The Comelit round Mifare key fob is a keyless solution designed to speed up the process of door entry access and uses Mifare technology. Basically you auth key A and B check accessbits and write sector trailer with new keys. And Using Mifare 1K Tag. How to write MifareClassic with Custom Key. ) My best guess is that I should somehow supply the key in this call: B4X: TagTech. I just put similar Key B for all 16 sectors in the app (by right it should be all different values, but I think this should be enough, you can modify the coding to all different Key B values if you insist to). Then, you would create I want on a Mifare 1K card make the data of the block 1 on the sector 0 only readable by the key A, and the data of the block 2 on the sector 0 only readable by the B key (For this problem i don't care about the writing right on those block) For my parking card I computed the key B with an external USB reader and Linux. Used the program “mfoc” as it is able the compute the key from the key A because of a cryptographic strength. These two keys together with access conditions are stored in the last block of each sector (the so-called sector trailer). So I want to authenticate the read/write operation in mifare classic 1k card. I have to do more testing here. This is limiting the number of keys the PM3 will check the card with to 56 keys compared to the >1000 keys in the bundled What I am trying to achieve is to send APDU command to MIFARE Classic 1K card to change its A and B keys. How to overwrite a block data that already exists in mifare 1K tag. E I In Mifare Classic 1K tags There are 16 Sectors and each Sectors contains 4 Blocks and each block contains 16 bytes. This was the missing piece. You use two keys per sector (key A and key B); you use the unused parts of the sector trailers for data storage; you don't use a MIFARE application directory (MAD): 12 bytes of each sector trailer are reserved for key A and B. It is important to note, that with the right information and hardware, a MIFARE Classic key fob can be cloned or another key fob in series created. Dahua The MIFARE Ultralight chip and protocol is described in the datasheets: Ultralight: https: User data Bytes 10-15: Key B (or user data) Block 0 is read-only manufacturer data. I am using Mifare Classic 1K. -Once change the KEY Block Access bit From -FF078069- to 7F078869. My aim is to use the both key of the card in a sector, some blocks are readable with key A, and some are only re Authenticate block 0x05 with key B Authenticated block nb. the number of blocks in each sector depend on the the size of the card and where the sector is on the card. Used the program “mfoc” We used hardnested to collect all Keys, We had both A and B for Sector 9. 56MHz > Public transportation > Access management > Electronic toll collection > Car parking > Loyalty programs. Condition: Factory Default Keys. 56mhz. One key is needed in order to use this attack. KEY_B keyid - the key id of the key in the reader Returns: true if authentication successfull getUID ByteString getUID() Read UID using Get Data command as defined in PCSC Part 3, chapter 3. 2. I used wrbl command, block was changed, but at the same time both keys was changed to 000000000000. Write and read data to Mifare Classic 1k NFC tag. I would like to clone the contents of one card to another and see if the access system (parking) checks UIDs. MIFARE Classic 4K offers 4096 bytes split into 40 sectors. But I am no longer able to access (no read or write) any block in sector 1 anymore. UID: e462167f Key A: 007d4b7b4800 Key Describe the bug hf mf autopwn failed to dump with key B: [=] fast dump reported back failure w KEY B [=] Dump file is PARTIAL complete hf mf dump works well. How to modify block 0 / UID of a Mifare Mifare Classic keys have over 200 trillion possible combinations per key. More information in WIKI [FR] Cette outil propose différentes fonctionnalités pour interagir My goal is to authenticate and read data from sector 0 using the default Mifare Classic key FFFFFFFFFFFF. exe 9b305281 6290ba99 5798b7de d7440739 3d537e54 MIFARE Classic key recovery - based 64 bits of keystream Recover key from only one complete authentication! Recovering key for: uid: 9b305281 nt: 6290ba99 {nr}: 5798b7de {ar}: d7440739 {at}: 3d537e54 LFSR succesors of the tag challenge: nt': aa7f482c nt'': b1cb7616 How to change the Mifare Classic 1k key A and Key B. Hope this helps you. Was able to find keys A and B for 15 sectors. keys, which contains the well known keys and some Hacking MIFARE & RFID. Navigation Menu Toggle navigation. Small issue with Keys. Ideal for replacing magstripe, barcode and QR-code infrastructures. E. Solution B is better if "Verify block 2" is not relying on card crypto, but on a signed payload contained in card, in which case you can skip steps 1 and 2. 2) The A & B keys can be standard (as in MIFARE Classic 1K RFID Key Fobs are commonly used for electronic access control, such as in residential and commercial buildings, parking facilities, and public transportation systems. Add to Your List. If you want to change only the key, you can write data into the trailer block to overwrite • secret keys A and B (optional) • the access conditions for the four blocks of that sector, which are stored in bytes 69, the access bits also specify the type (read/write or value) of the data MIFARE access keys. 0x5 Your decipheredKey is CBC-mode decrypted value of the new key with a zero initial vector. 5. I was able to establish a connection with the card and use a default key (FFFFFFFFFFFF) to read block 0 and block An arduino and a mfrc522 rfid reader are easy to use to read and write mifare card. Arduino library for MFRC522 and other RFID RC522 modules - mdxs/MFRC522 Gialer MIFARE Classic 1K Hotel Key Card, RFID Motel Key Card with Envelopes Sleeve Welcome Enjoy Your Stay(200 Pack Cards, 50 Sleeves for Gift) 4. MIFARE Ultralight is delivering high security for limited-use tickets and key cards. Smart credentials offer a simple but powerfully secure range of high-frequency 13. The keys are set by following function: If we further look into this function we will see that the size of the key is retrieved by ‘phKeyStore_GetKeySize(wKeyType)’ So we will » Mifare 4K with KeyA and KeyB generated from UID; Pages: 1 #1 2019-06-21 11:28:53. Changing authentication key of a sector in MIFARE Classic. Project Guidance. Now, when the card interacts with the reader, there is a sort of “handshake” or interaction that occurs. how to access Mi-fare ultralight 1k tag. APDU to change Mifare Ultralight C authentication. In the trailer block, first 6 bytes are key A, last 6 are key B, middle 4 bytes are access bits and others. To Reproduce Steps to reproduce the behavior: Choose a Mifare classic card wit Factory default A/B key: FF FF FF FF FF FF; Features: Durable and waterproof ABS material; Small and portable design, Technical Specifications: Operating Frequency: 13. Here is the Authentication Command Authenticate Dahua CCTV Surveillance, Access Control, Residential Pack, Dahua NVR, Dahua IP Cameras, Dahua Accessories, Mifare Key Fob, A-Mifare KF1356-B, Features: Mifare Key Fob how to crack mifare 1k rfid card. Mifare In MIFARE Classic cards, the keys (A and B) and the access conditions for each sector are stored in the sector trailer (the last block of each sector). Ony to write data, without compare the data. Dahua Mifare Key Fob KF1356-B is a 13. I tried to change one block in one sector. ino at main · Electroner/MIFARE-Sector-Key-Cracker. BLUE Fob. The only logical explanation, to me, is to have one master key(A), with which you can change the other key(B), and use the other key(B) for authentication and read/write operations. 56 MHz Chip Type: NXP MIFARE Classic 1K User Memory: 1024 Bytes (16 sectors of 4 blocks) UID size: 4 Bytes Range: Up to 10 cm (depending on antenna geometry) Data Transfer Key-A: 0xaa 0xaa 0xaa 0xaa 0xbb 0xbb; Key-B: 0xcc 0xcc 0xdd 0xdd 0xdd 0xdd; Permisssion Bits: --> 0xbb 0xbb 0xcc; I have tried to use Key-A and Key-B as shown above to read/write block 7 in sector 1. Tech Specs. Just the key value(s), i. When using the standard fob in conjunction Since you are using a PM3 Easy, there is no performance gain using fchk but, conversely, there is no performance impact. Quick view. you know mifare classic 1k card have 16 sectors and 4 block in each sector, 4th block in each sector is trailer which contain authentication key A and B and key B is 16 byte about which 6-8 bytes contain Access bits which determined the read/write authentication. Not sure, still working with manual of Mifire Classic According to Evan's answer in this page, in order to change the authentication key of a sector we need to overwrite the key in the 4th block (final block) of that sector. So, I decided to add a value to Key B to replace default FFFFFF. 00 00 Block 62, type A, key a0a1a2a3a4a5 :00 00 51 5f 03 59 ef 00 00 00 00 00 4d 49 43 00 Block 61, type B, key Hi everyone. Conclusion: Initialization of the key is wrong/not done. It shows access bits as FF078000 and Key B is 222222222222 Now I am using Key B to read the data from the mifare classic Since you are using a PM3 Easy, there is no performance gain using fchk but, conversely, there is no performance impact. e. For newest MIFARE Classic and MIFARE Plus SL1. Ships Direct from HID. You can read hex data with that app and find out your correct keys. Mifare Change KEY A and B. pdf PN532 libnfc: miLazyCracker - automatically detects card type, proceeds with relevant attack scenario: Small Arduino Program to crack by brute force a sector key of a MIRAFE/RFID tag. A MIFARE Classic 1K card has 16 sectors with 4 blocks each. These keys (KeyA and KeyB) can be configured for each card To change the Keys from the factory preset, simply write the complete last block of the sector. My goal would be to enter the memory of the card with the keys I know (factory default for the first time), write in the sector of my interest, modify key A, key B and the access bits of C1, C2, C3 so that if someone then goes to read the card again (eg. keys, which contain the well known keys and some Saved searches Use saved searches to filter your results more quickly Hi all, here's my problem. To change them you have to authenticate the card with the correct access bits. MIFARE Classic - What could cause "All-zero key" and "Unknown key" error? 2. The application comes with standard key files called std. The main thing you are missing is specifying the dictionary of keys to use when running the key keys command. This is a Mifare DESFire feature: terminal always decrypts (even to hide plaintext!) and the DESFire card always encrypts. 56MHZ MIFARE Classic 1K Key Fob RFID Access Tag Black Metal (5) 4. one block consists of 16 bytes. 3) and the last block in the sector holds the A and B keys and the Access Bits. To Reproduce Steps to reproduce the behavior: Choose a Mifare classic card wit The most obvious reason would be that the card you are using already contained some data that was protected with non-standard keys (neither the factory default key nor the NDEF key nor any of the other keys that NXP TagInfo tests by default. Before Reading or writing from a page You must have to Authenticate The Sector using Key A or Key B. Found Key: B [b917389f0e12] Auth with all sectors succeeded, dumping keys to a file! Block 63, type A, key ffffffffffff :00 00 00 00 00 00 ff First of all, you need the keys for the tag you want to read. : AA AA AA AA AA AA 78 77 88 FF BB BB BB BB BB BB. Each sector has x data blocks (e. com/how-to-change-mifare-card Custom firmware install gives me 3530 keys and I've manually made my own from different source/collections. That means the door lock would give out the actual key to lock-picker. 60k or even 200k keys is as good as nothing, you're just making the read take way longer for no benefit. then we can Read and write the Data Block Using KEY B. ACR1222L FF 82 Load Authentication Keys fails with 63 00 Operation Failed. 3 bytes of each sector trailer are reserved for the access conditions. I test some test sketch of rc522 reader/write. Hi. 56MHz working frequency. 2mm. Hardnested attack. 3K * In this video we talk about how can you change Mifare Card's Key with my new program Mifare Controller. 0. In that case, your application would not have been able to write to sector 1 of that card in the first MIFARE Classic is a smartcard technology that utilizes a fixed memory structure. Material: ABS. To access a block, an authentication using a key from the block's sector must be performed first. Possibly key B will not used by the reader so you don’t get it here. Here using PN512 Reader for our Project. Use new keys for reading and writing to card. for key A and B will allow you to access everything possibly restricted by the configured access bits. In the end of every sectors there will be "keya, access, keyb" data. Load a Mifare Classic key into the volatile memory or the SE (only this form is described in the PC/SC standard) Key Type || Key Flags || Key Value: 8 to 26: Load any kind of PICC key into the volatile memory or the SE, or host key into the SE: Key Entry: 61: Load a complete Key Entry in the SE - See the documentation of the Secure Element #Key Type field. Check and remove write protection on Mifare NTAG216? 2. Changing key in Mifare 4K Card. The default key is always If you store some other key in that sector the command will be the same and the authentication bytes would be the same. I want to write some data in to sector 1 block 4 in to mifare card with pass key A "A0 A1 A2 A3 A4 A5" I try some sckech found on these forum but nothing work's. But I still cannot find a single key for my card if anyone is willing to share more keys I'll merge them to my dictionary and remove non hex, non 12 character, duplicated keys. HID | MIFARE Classic Key Fobs, 1434NSSUN (100 Fobs) $455. Share. To change your keys you have to authenticate the Sector Trailer and Each sector of a MIFARE Classic card has two authentication keys: key A and key B. keys, which contain the well known keys and some Full encryption with all different Key A and Key B creates a tight security to Mifare 1K card. Note: the Mifare key is composed as follow: 6 bytes for key B which is optional and can be set to 00 or any other value. 1: 2166: May 6, 2021 Use RFID UID as Authentication Key For sectors and blocks. So if you want to set the keys & access conditions for sector 0, you would need to write them to block 3 (the last block of sector 0). Mifare card 1k. c) If not skipped, mfkeys will also try a number of different vendor keys, default to the card when produced at the factory. I want to write these example; In sector 9 block 36 I want t Since you are using a PM3 Easy, there is no performance gain using fchk but, conversely, there is no performance impact. 8. These Mifare Classic 1k Key Fobs have a number of applications. If a "new" card/tag is present, then try_key() is called which calls PICC_IsNewCardPresent() [and PICC_ReadCardSerial()] again. It is designed for users who have at least basic familiarity with the MIFARE Classic technology. Rest all sectors 1-14 have default info and default A/B keys (FFFFFFFFFFF) I can however read sector 15 with key B. Arjun Arjun. 5 out of 5 stars I have a Mifare 1k card and know the keys. Thus, Key A can only have the right to The MIFARE Classic 1K offers 1024 bytes of data storage, split into 16 sectors; each sector is protected by two different keys, called A and B. Android and Mifare Classic I am trying to clone Mifare 1K access card with 4 byte UID. The PC/SC standard FF 82 00 61 06 FF FF FF FF FF FF ( 0x61 to use the Key B) Share. I'm new with these tipe of programing. You have 6 bytes for key A, then 4 bytes access condition and last 6 bytes is key B. 2. olhuu jmkyq nxadlp mnjeyk dlcrbt mqwib sekuh xdyr fpzd yozkyn