2.2.3.2.2 Crypto Payload 0x85 Encryption Flag Not Set
If the encryption flag is not set in the flags field of the ISAKMP header, the format is as follows.
The following diagram shows the format of the Crypto Payload 0x85 Encryption Flag Not Set.
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1 |
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2 |
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3 |
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seqNUM |
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Initialization_Vector (optional) |
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... |
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seqNUM (4 bytes): The seqNUM field is a sequence number for the next expected packet number. Sequence number generation is specified in section 3.1.1.
Initialization_Vector (8 bytes): The Initialization_Vector field is an optional field that SHOULD<8> be present. The presence of the Initialization_Vector is indicated by the length of the Crypto payload (greater than 8 bytes if the Initialization_Vector is present; otherwise, 8 bytes).
Note The Crypto payload with the encryption flag not set MUST be followed by a variable-length sequence of unencrypted Authenticated Internet Protocol payloads, each starting with the Generic payload header. In addition, the next payload field of the Generic payload header of the Crypto payload MUST be set to the payload type of the first payload in the clear-text payload sequence that is carried by the Crypto payload.