NULL

The NULL value is encoded into a TLV triplet that begins with a Tag value of 0x05, a Length of 0x00, and no Value byte as shown by the following illustration.

The fifth line of the following example, adapted from the PKCS #10 Encoded ASN.1 topic, shows an encoded NULL value. The first byte is 0x05, and the second byte is 0x00. There is no content byte.

30 81 9f                                ; SEQUENCE (9f Bytes)
|  30 0d                                ; SEQUENCE (d Bytes)
|  |  06 09                             ; OBJECT_ID (9 Bytes)
|  |  |  2a 86 48 86 f7 0d 01 01  01    ; 1.2.840.113549.1.1.1
|  |  05 00                             ; NULL (0 Bytes)
|  03 81 8d                             ; BIT_STRING (8d Bytes)
|     00
|     30 81 89                          ; SEQUENCE (89 Bytes)
|        02 81 81                       ; INTEGER (81 Bytes)
|        |  00
|        |  8f e2 41 2a 08 e8 51 a8  8c b3 e8 53 e7 d5 49 50
|        |  b3 27 8a 2b cb ea b5 42  73 ea 02 57 cc 65 33 ee
|        |  88 20 61 a1 17 56 c1 24  18 e3 a8 08 d3 be d9 31
|        |  f3 37 0b 94 b8 cc 43 08  0b 70 24 f7 9c b1 8d 5d
|        |  d6 6d 82 d0 54 09 84 f8  9f 97 01 75 05 9c 89 d4
|        |  d5 c9 1e c9 13 d7 2a 6b  30 91 19 d6 d4 42 e0 c4
|        |  9d 7c 92 71 e1 b2 2f 5c  8d ee f0 f1 17 1e d2 5f
|        |  31 5b b1 9c bc 20 55 bf  3a 37 42 45 75 dc 90 65
|        02 03                          ; INTEGER (3 Bytes)
|           01 00 01

Related topics

ASN.1 Type System

DER Encoding of ASN.1 Types