# Cryptographic Test Cases This page describes tests a provider can write to verify the cryptographic components of their provider implementation. Google recommends implementing these tests early to ease Fast Pair integration. ## Test Cases These cases cover: - Hashing - The Bloom Filter - AES Encryption and Public Key Exchange - Message enciphering and deciphering ### SHA-256 Hashing Input value: 0x11, 0x22, 0x33, 0x44, 0x55, 0x66 Hashed result: 0xBB, 0x00, 0x0D, 0xDD, 0x92, 0xA0, 0xA2, 0xA3, 0x46, 0xF0, 0xB5, 0x31, 0xF2, 0x78, 0xAF, 0x06, 0xE3, 0x70, 0xF8, 0x69, 0x32, 0xCC, 0xAF, 0xCC, 0xC8, 0x92, 0xD6, 0x8D, 0x35, 0x0F, 0x80, 0xF8 ### AES Encryption Input value: 0xF3, 0x0F, 0x4E, 0x78, 0x6C, 0x59, 0xA7, 0xBB, 0xF3, 0x87, 0x3B, 0x5A, 0x49, 0xBA, 0x97, 0xEA Secret key: 0xA0, 0xBA, 0xF0, 0xBB, 0x95, 0x1F, 0xF7, 0xB6, 0xCF, 0x5E, 0x3F, 0x45, 0x61, 0xC3, 0x32, 0x1D Encrypted output: 0xAC, 0x9A, 0x16, 0xF0, 0x95, 0x3A, 0x3F, 0x22, 0x3D, 0xD1, 0x0C, 0xF5, 0x36, 0xE0, 0x9E, 0x9C ### ECDH Key Exchange Bob's private key: 0x02, 0xB4, 0x37, 0xB0, 0xED, 0xD6, 0xBB, 0xD4, 0x29, 0x06, 0x4A, 0x4E, 0x52, 0x9F, 0xCB, 0xF1, 0xC4, 0x8D, 0x0D, 0x62, 0x49, 0x24, 0xD5, 0x92, 0x27, 0x4B, 0x7E, 0xD8, 0x11, 0x93, 0xD7, 0x63 Bob's public key: 0xF7, 0xD4, 0x96, 0xA6, 0x2E, 0xCA, 0x41, 0x63, 0x51, 0x54, 0x0A, 0xA3, 0x43, 0xBC, 0x69, 0x0A, 0x61, 0x09, 0xF5, 0x51, 0x50, 0x06, 0x66, 0xB8, 0x3B, 0x12, 0x51, 0xFB, 0x84, 0xFA, 0x28, 0x60, 0x79, 0x5E, 0xBD, 0x63, 0xD3, 0xB8, 0x83, 0x6F, 0x44, 0xA9, 0xA3, 0xE2, 0x8B, 0xB3, 0x40, 0x17, 0xE0, 0x15, 0xF5, 0x97, 0x93, 0x05, 0xD8, 0x49, 0xFD, 0xF8, 0xDE, 0x10, 0x12, 0x3B, 0x61, 0xD2 Alice's private key: 0xD7, 0x5E, 0x54, 0xC7, 0x7D, 0x76, 0x24, 0x89, 0xE5, 0x7C, 0xFA, 0x92, 0x37, 0x43, 0xF1, 0x67, 0x77, 0xA4, 0x28, 0x3D, 0x99, 0x80, 0x0B, 0xAC, 0x55, 0x58, 0x48, 0x38, 0x93, 0xE5, 0xB0, 0x6D Alice's public key: 0x36, 0xAC, 0x68, 0x2C, 0x50, 0x82, 0x15, 0x66, 0x8F, 0xBE, 0xFE, 0x24, 0x7D, 0x01, 0xD5, 0xEB, 0x96, 0xE6, 0x31, 0x8E, 0x85, 0x5B, 0x2D, 0x64, 0xB5, 0x19, 0x5D, 0x38, 0xEE, 0x7E, 0x37, 0xBE, 0x18, 0x38, 0xC0, 0xB9, 0x48, 0xC3, 0xF7, 0x55, 0x20, 0xE0, 0x7E, 0x70, 0xF0, 0x72, 0x91, 0x41, 0x9A, 0xCE, 0x2D, 0x28, 0x14, 0x3C, 0x5A, 0xDB, 0x2D, 0xBD, 0x98, 0xEE, 0x3C, 0x8E, 0x4F, 0xBF Generated shared key (either Alice's public + Bob's private or Bob's public + Alice's private): 0x9D, 0xAD, 0xE4, 0xF8, 0x6A, 0xC3, 0x48, 0x8B, 0xBA, 0xC2, 0xAC, 0x34, 0xB5, 0xFE, 0x68, 0xA0, 0xEE, 0x5A, 0x67, 0x06, 0xF5, 0x43, 0xD9, 0x06, 0x1A, 0xD5, 0x78, 0x89, 0x49, 0x8A, 0xE6, 0xBA ### AES Key from ECDH Shared Secret This is step 1b (AES key generation) in the GATT [procedure](https://developers.google.com/nearby/fast-pair/specifications/service/gatt#procedure "Procedure"). ECDH shared key: 0x9D, 0xAD, 0xE4, 0xF8, 0x6A, 0xC3, 0x48, 0x8B, 0xBA, 0xC2, 0xAC, 0x34, 0xB5, 0xFE, 0x68, 0xA0, 0xEE, 0x5A, 0x67, 0x06, 0xF5, 0x43, 0xD9, 0x06, 0x1A, 0xD5, 0x78, 0x89, 0x49, 0x8A, 0xE6, 0xBA Generated AES key: 0xB0, 0x7F, 0x1F, 0x17, 0xC2, 0x36, 0xCB, 0xD3, 0x35, 0x23, 0xC5, 0x15, 0xF3, 0x50, 0xAE, 0x57 ### Bloom Filter Random salt: 0xC7C8 First account key added to the filter (combine with the above random salt): 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0x00, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF Resulting bloom filter: 0x02, 0x0C, 0x80, 0x2A Battery data (if it is contained in the advertisement): 0b00110011, // length = 3, show UI indication. 0b01000000, // left bud: not charging, battery level = 64. 0b01000000, // right bud: not charging, battery level = 64. 0b01000000 // case: not charging, battery level = 64. Resulting bloom filter with battery data: 0x01, 0x01, 0x46, 0x0A Second account key added to the filter (combine with the above random salt): 0x11, 0x11, 0x22, 0x22, 0x33, 0x33, 0x44, 0x44, 0x55, 0x55, 0x66, 0x66, 0x77, 0x77, 0x88, 0x88 Resulting bloom filter from both added account keys: 0x84, 0x4A, 0x62, 0x20, 0x8B Battery data (if it is contained in the advertisement): 0b00110011, // length = 3, show UI indication. 0b01000000, // left bud: not charging, battery level = 64. 0b01000000, // right bud: not charging, battery level = 64. 0b01000000 // case: not charging, battery level = 64. Resulting bloom filter from both added account keys with battery data: 0x46, 0x15, 0x24, 0xD0, 0x08 ### AES-CTR Encryption Input data: "Someone's Google Headphone" with utf-8 encoding 0x53, 0x6F, 0x6D, 0x65, 0x6F, 0x6E, 0x65, 0x27, 0x73, 0x20, 0x47, 0x6F, 0x6F, 0x67, 0x6C, 0x65, 0x20, 0x48, 0x65, 0x61, 0x64, 0x70, 0x68, 0x6F, 0x6E, 0x65 Secret key: 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF Nonce: 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 Expected encryption result: 0xEE, 0x4A, 0x24, 0x83, 0x73, 0x80, 0x52, 0xE4, 0x4E, 0x9B, 0x2A, 0x14, 0x5E, 0x5D, 0xDF, 0xAA, 0x44, 0xB9, 0xE5, 0x53, 0x6A, 0xF4, 0x38, 0xE1, 0xE5, 0xC6 ### HMAC-SHA256 Input data: 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0xEE, 0x4A, 0x24, 0x83, 0x73, 0x80, 0x52, 0xE4, 0x4E, 0x9B, 0x2A, 0x14, 0x5E, 0x5D, 0xDF, 0xAA, 0x44, 0xB9, 0xE5, 0x53, 0x6A, 0xF4, 0x38, 0xE1, 0xE5, 0xC6 Secret key: 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF Expected HMAC-SHA256 result: 0x55, 0xEC, 0x5E, 0x60, 0x55, 0xAF, 0x6E, 0x92, 0x61, 0x8B, 0x7D, 0x87, 0x10, 0xD4, 0x41, 0x37, 0x09, 0xAB, 0x5D, 0xA2, 0x7C, 0xA2, 0x6A, 0x66, 0xF5, 0x2E, 0x5A, 0xD4, 0xE8, 0x20, 0x90, 0x52 ### Encode personalized name to additional data packet Input data: "Someone's Google Headphone" with utf-8 encoding 0x53, 0x6F, 0x6D, 0x65, 0x6F, 0x6E, 0x65, 0x27, 0x73, 0x20, 0x47, 0x6F, 0x6F, 0x67, 0x6C, 0x65, 0x20, 0x48, 0x65, 0x61, 0x64, 0x70, 0x68, 0x6F, 0x6E, 0x65 Secret key: 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF Nonce: 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 Expected additional data packet: 0x55, 0xEC, 0x5E, 0x60, 0x55, 0xAF, 0x6E, 0x92, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0xEE, 0x4A, 0x24, 0x83, 0x73, 0x80, 0x52, 0xE4, 0x4E, 0x9B, 0x2A, 0x14, 0x5E, 0x5D, 0xDF, 0xAA, 0x44, 0xB9, 0xE5, 0x53, 0x6A, 0xF4, 0x38, 0xE1, 0xE5, 0xC6 ### Decode additional data packet to get personalized name Input data: 0x55, 0xEC, 0x5E, 0x60, 0x55, 0xAF, 0x6E, 0x92, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0xEE, 0x4A, 0x24, 0x83, 0x73, 0x80, 0x52, 0xE4, 0x4E, 0x9B, 0x2A, 0x14, 0x5E, 0x5D, 0xDF, 0xAA, 0x44, 0xB9, 0xE5, 0x53, 0x6A, 0xF4, 0x38, 0xE1, 0xE5, 0xC6 Secret key: 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF Expected name: "Someone's Google Headphone" with utf-8 encoding 0x53, 0x6F, 0x6D, 0x65, 0x6F, 0x6E, 0x65, 0x27, 0x73, 0x20, 0x47, 0x6F, 0x6F, 0x67, 0x6C, 0x65, 0x20, 0x48, 0x65, 0x61, 0x64, 0x70, 0x68, 0x6F, 0x6E, 0x65 ### Encrypted connection status field Field length and type: 0b001100101 (length = 3, type = connection status field) Connection state: 0b10000101: * on head detection = 1 * connection availability = 0 * focus mode = 0 * auto-reconnected = 0 * connection state = 0x5 (A2DP with AVRCP) Custom data: 0x38 Connected devices bitmap: 0b00001001 Connection status field raw data (combine above 4 bytes): 0x35853809 In use account key (this is the Key): 0x04, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0x00, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF Non-in use account key: 0x04, 0x11, 0x22, 0x22, 0x33, 0x33, 0x44, 0x44, 0x55, 0x55, 0x66, 0x66, 0x77, 0x77, 0x88, 0x88 Random salt: 0xC7C8 Account key filter (this is IV): this is generated by changing the first byte of in use account key from 0b00000100 to 0b00000110. 0x8C, 0xA9, 0x0C, 0x08, 0x1C Encrypted connection status field: 0xF4, 0xBB, 0x40, 0x6F > [!NOTE] > **Note:** this is encrypted by the original account key, in other words, the first byte of the key is 0x04 not 0x06