| Internet-Draft | SHA-3 in IKEv2 and IPsec | July 2025 |
| Salter, et al. | Expires 4 January 2026 | [Page] |
This document specifies the use of KMAC128 and KMAC256 within the Internet Key Exchange Version 2 (IKEv2), Encapsulating Security Payload (ESP), and Authentication Header (AH) protocols. These algorithms can be used as integrity protection algorithms for ESP, AH and IKEv2, and as Pseudo-Random Functions (PRFs) for IKEv2. Requirements for supporting signature algorithms in IKEv2 that use SHA3-256, SHA3-384, SHA3-512, SHAKE128 and SHAKE256 are also specified.¶
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Removed support for HMAC-SHA3. The draft now only covers KMAC as a PRF and integrity protection transform, and SHA3 and SHAKE for use with the Digital Signature authentication method.¶
Corrected several test vector errors.¶
Added notes about draft-smyslov-ipsecme-ikev2-prf-plus.¶
Changed API symbols to better align with RFC 7296.¶
Several wording changes for clarity, error corrections, etc.¶
Added section about considerations for implementers and future IKEv2 documents.¶
[FIPS-202] specifies both the SHA3-256, SHA3-384 and SHA3-512 cryptographic hash functions, and the SHAKE eXtendable-output functions (XOFs). [SP-800-185] specifies KMAC128 and KMAC256, which use variants of SHAKE128 and SHAKE256 respectively to create a message authentication code (MAC). Like the output of SHAKE, the MAC output of KMAC can be of any length required by the application.¶
This document specifies how to use KMAC128 and KMAC256 with IKEv2 and IPsec for integrity protection, and as a PRF for IKEv2. It also allocates values used for announcing support for SHA3-256, SHA3-384, SHA3-512, SHAKE128, and SHAKE256 when generating and validating signatures in IKEv2.¶
EDNOTE: Support for SHA3-224 is not included, though draft-ietf-lamps-cms-sha3-hash includes support for SHA3-224 with ECDSA.¶
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶
Additionally, this document uses several terms to collectively refer to sets of algorithms.¶
The term "SHA-3 cryptographic hash functions" is used to collectively refer to SHA3-256, SHA3-384 and SHA3-512.¶
The term "KMAC" is used to collectively refer to KMAC128 and KMAC256.¶
The term "SHA-3" (without any other qualifiers) is used to collectively refer to the cryptographic algorithms defined in [FIPS-202] and [SP-800-185].¶
The term "SHA-2" (without any other qualifiers) is used to collectively refer to SHA-256, SHA-384, and SHA-512.¶
The term "SHAKE" is used to collectively refer to SHAKE128 and SHAKE256.¶
SHA-3 is a collection of cryptographic algorithms that all utilise the Keccak sponge construction. [FIPS-202] describes the SHA-3 cryptographic hash functions, which produce a fixed-length digest for any length of input. These hash functions are intended to be used in the same manner and contexts as other traditional hash functions such as SHA-2. [FIPS-202] also describes the SHAKE XOFs. An XOF differs from a traditional hash function in that the length of the XOF's output can be chosen by the application that uses it. [SP-800-185] describes cSHAKE, a customisable version of SHAKE, and KMAC, which is a PRF and keyed hash function that utilises cSHAKE. Like SHAKE and cSHAKE, the length of KMAC's output is application-dependent.¶
SHA-3 was specified to provide applications with an alternative to SHA-2, which is based on the Merkle-Damgård construction. Use of the Merkle-Damgård construction in SHA-2 means that length extension attacks are possible if SHA-2 isn't used correctly. At the time of writing, use of SHA-2 in IPsec is believed to be secure, and hence there is no security motivation to migrate away from SHA-2 to SHA-3 in this context. However, in the event that a significant attack on SHA-2 is discovered, SHA-3 will be an immediately viable alternative.¶
Migration to use of post-quantum algorithms in IKEv2 may make use of SHA-3 more appealing for minimal implementations of IPsec, as [ML-KEM], [ML-DSA], [SLH-DSA], and [FALCON] all make use of SHA-3 internally. Since support for SHA-3 is required to implement these algorithms, some implementers may find it preferable to implement SHA-3, and only SHA-3, if interoperability with general-purpose IKEv2 and IPsec implementations is not required.¶
SHA-2 is used with HMAC in IKEv2 and IPsec. Whilst SHA-3 can be used with HMAC, KMAC is more efficient as it directly uses the Keccak sponge function to produce a MAC, rather than treating Keccak as a traditional cryptographic hash function and then feeding that hash function into a separate MAC algorithm. Therefore, this document only specifies use of KMAC, and not of HMAC-SHA3.¶
The basic API for KMAC is defined below. The symbols used in this API description conform to those used for prf+ in [RFC7296], which clash with the API described in [SP-800-185]. [RFC7296] uses S to describe the input string to prf+, whereas [SP-800-185] uses that symbol for the optional customization string. KMAC implementations used in IKEv2 and IPsec do not need to conform to these APIs exactly; they are merely used in this document for illustrative purposes.¶
For the purposes of this document, the API for KMAC is defined as:¶
KMAC(K, S, L, C) -> Z¶
where:¶
K is the key. It is a bit string of length between zero and (2^2040)-1 bits, inclusively.¶
S is the input string. It is a bit string of any length, including zero.¶
L is an integer representing the requested output length in bits. This parameter is typically fixed in the context of IPsec, except when extracting key material using prf+ in IKEv2, where it depends on the length of key material needed by the negotiated cipher suite.¶
C is an optional customization string. It is a bit string of length between zero and (2^2040)-1 bits, inclusively.¶
Z is the output string of KMAC, which is a message authentication code. It is a bit string of length L.¶
Per [SP-800-185], the length of the key input K input to KMAC MUST be less than 2^2040 bits. In the context of IKEv2 and IPsec, there is no situation where a key that long would be expected. Initiator and Responder nonces Ni and Nr are used as inputs to IKEv2 PRF calls, although the length of these nonces combined cannot exceed 4096 bits. Pre-shared keys used for authentication in IKEv2 are used as keys with PRFs negotiated by IKEv2, and have no upper bound on their length. Therefore, KMAC implementations used with IKEv2 MUST at minimum accept values of K up to and including 4096 bits in length. Implementations MAY restrict the size of pre-shared key inputs such that they do not exceed 4096 bits.¶
There is no algorithm-defined minimum size for the key input to KMAC, but Table 2 and Table 3 list the recommended key sizes to be used within the context of IKEv2 and IPsec, aligned to the security strength of each algorithm. Using a key smaller than the security strength of the chosen KMAC algorithm undermines the security properties of that algorithm. Where IKEv2 is used to create security associations, the size of most PRF keys is automatically managed at the protocol level, and there is no risk of selecting an undersized key in these cases. However, the size of keys used for PRFs in IKEv2 cannot always be controlled.¶
As an example, in the case of pre-shared keys used for authentication or protection against a quantum computer as in [RFC8784], those secrets are used as the key input to a PRF negotiated by IKEv2. Those pre-shared keys could be arbitrarily chosen by a user or derived from a password rather than securely generated, even though [RFC7296] strongly discourages this practice. Keys chosen in this manner may be shorter than any recommended key size. IKEv2 implementations following the recommendation laid out in [RFC7296] can impose constraints on suitable pre-shared keys.¶
Additionally, Ni and Nr are variable length and are used as the key for KMAC. [RFC7296] states that each of these nonces MUST be at least 128 bits in size, and MUST be at least half the preferred key size for the negotiated PRF. If an IKEv2 peer sends an undersized nonce, the message containing that nonce can be rejected in the same way as any malformed IKEv2 message would be. Conformant KMAC implementations SHOULD reject keys that do not meet the security strength of the corresponding algorithm.¶
The input string S can be a variety of lengths in practice, but in the context of IKE and IPsec the length will always be a multiple of eight, as IKE and IPsec only operate on entire octets. Similarly, KMAC's output length parameter L will always be a multiple of eight. Since the length of output required from KMAC is always known in advance, KMAC with arbitrary-length output as described in Section 4.3.1 of [SP-800-185] is never used, and thus L is never set to 0.¶
KMAC's customization string C is fixed to a specific value depending on the context in which KMAC is used. Future specifications may define additional customization strings, but the set of valid strings used by KMAC in IKEv2 and IPsec will always be fixed-length context-dependent strings specified in IETF RFCs rather than dynamically created, e.g. via random data.¶
EDNOTE: The customization string isn't strictly necessary and may make implementation a bit harder, but they seem valuable in that we're placing a clear divide between two places with different rules on how KMAC is used. Note that [I-D.smyslov-ipsecme-ikev2-prf-plus] specifies the customization string be set to the empty string. Whatever decision is made, we should ensure the two documents align in the end.¶
Since the length of the input string S for KMAC varies, and KMAC operates on fixed-size input blocks, padding is required to use KMAC in IKEv2 and IPsec. The padding scheme for KMAC is specified in [SP-800-185]. A KMAC implementation conformant to that document is sufficient; no additional padding is required to use these algorithms in IKEv2 or IPsec.¶
When KMAC is used as the PRF for an IKE SA, the size of the key input K is variable. If the size of a KMAC key is greater than the preferred key size as shown in Table 2, the key is used in its entirety without any kind of shortening or truncation. As described in [SP-800-185], keys are always padded up to a multiple of the rate of the underlying Keccak sponge function; that is, 168 bytes and 136 bytes for KMAC-128 and KMAC-256 respectively. Any KMAC implementation conformant with [SP-800-185] is suitable for use in IKEv2 and IPsec; no protocol-specific additional padding of keys is required.¶
Table 1 describes the general properties of KMAC, with the HMAC-SHA2 algorithms also listed for comparison purposes. The maximum security strengths listed are taken from [SP-800-57]. Note that these are maximum security strengths. Using keys that are shorter than the maximum security strength will constrain the maximum security strength of the chosen algorithm to be no higher than the length of that key. Keys that contain insufficient entropy to meet the maximum security strength constrain the maximum security of the chosen algorithm to be no higher than the bits of entropy represented in the key.¶
| Algorithm Name | Output Length (bits) | Maximum Security Strength (bits) |
|---|---|---|
| HMAC-SHA-256 | 256 | >=256 |
| HMAC-SHA-384 | 384 | >=256 |
| HMAC-SHA-512 | 512 | >=256 |
| KMAC128 | Variable | 128 |
| KMAC256 | Variable | >=256 |
Table 2 presents the parameters of KMAC when it is used as a PRF in IKEv2, with the HMAC-SHA2 algorithms also listed for comparison purposes.¶
| Algorithm Name | PRF variant | Preferred Key Size (bits) | Output Length (bits) |
|---|---|---|---|
| HMAC-SHA-256 | PRF_HMAC_SHA2_256 | 256 | 256 |
| HMAC-SHA-384 | PRF_HMAC_SHA2_384 | 384 | 384 |
| HMAC-SHA-512 | PRF_HMAC_SHA2_512 | 512 | 512 |
| KMAC128 | PRF_KMAC_128 | 128 | 256, or length of output required for prf+ |
| KMAC256 | PRF_KMAC_256 | 256 | 512, or length of output required for prf+ |
The security strength of these algorithms is equal to the maximum security strength indicated for that algorithm in Table 1, unless the entropy of the supplied key is insufficient to meet that strength.¶
When key material is extracted from IKEv2's prf+ Key Derivation Function (KDF) for use with KMAC as a PRF in IKEv2, the length of keys extracted MUST conform to the preferred key sizes listed in Table 2.¶
EDNOTE: The KMAC output lengths have been aligned with HMAC, but if we're not depending on collision resistance, it seems like they could be reduced to 128/256 bits respectively? That would also mean that the PRF output would be suitable for use as a PRF key without requiring further modification, like HMAC.¶
Table 3 presents the parameters of KMAC when it is used for data origin authentication and integrity protection in IKEv2 and IPsec, with the HMAC-SHA2 algorithms also listed for comparison purposes.¶
| Algorithm Name | Integrity variant | Key Size (bits) | Output Length (bits) |
|---|---|---|---|
| HMAC-SHA-256 | AUTH_HMAC_SHA2_256_128 | 256 | 128 |
| HMAC-SHA-384 | AUTH_HMAC_SHA2_384_192 | 384 | 192 |
| HMAC-SHA-512 | AUTH_HMAC_SHA2_512_256 | 512 | 256 |
| KMAC128 | AUTH_KMAC_128 | 128 | 128 |
| KMAC256 | AUTH_KMAC_256 | 256 | 256 |
When used for authentication and integrity protection, KMAC message authentication codes are produced using a smaller value for the "requested output length" parameter L. In this case, the security strength of each given algorithm is constrained by its output length.¶
When key material is extracted from IKEv2's prf+ KDF for use with KMAC for data origin authentication and integrity protection in IKEv2 or IPsec, the length of keys extracted MUST conform to the key sizes listed in Table 3.¶
IKEv2 Security Associations (SAs) make use of a PRF for authentication purposes, and as a part of the prf+ Key Derivation Function (KDF). KMAC can act as the PRF for an IKE SA, but it is treated slightly differently to existing PRFs as it is capable of producing different output lengths depending on the context in which it is used.¶
With KMAC, the key K is either a fixed-length key (such as SK_d) that is the preferred key size for the variant of KMAC being used, or the length of K is dependent on other factors. When the PRF is used with nonce inputs as the key K (e.g. when generating SKEYSEED), or when the PRF is used with a pre-shared key as the input key K, the length of K depends on implementation-specific details, user configuration options, etc.¶
When KMAC is used as the PRF for an IKE SA, its "requested output length" parameter L and "customization string" parameter C are populated differently depending on whether KMAC is being used as a part of the prf+ construction in the IKEv2 KDF or not. This process is described in more detail in Section 9.1 and Section 9.2.¶
When used in IKEv2 as a PRF outside the prf+ construction, KMAC's output length L is 128 for KMAC128, and 256 for KMAC256. That is, the output length is the same size as the security strength and preferred key size of the given KMAC algorithm. Note that the situation is different when KMAC is used within the prf+ construction, as described in Section 9.2.¶
When KMAC is used as a PRF outside the prf+ construction, the customization string C is set to the ASCII character string "ikev2 prf", without null termination.¶
When KMAC is used in the prf+ construction, L is set to the length of the keying material required. That is, prf (K, S | 0x01) is the only step of the prf+ function that is ever required, as KMAC can produce a pseudorandom stream without the need to iteratively call prf as described in [RFC7296].¶
EDNOTE: the intent here is to keep prf+ (sort of) the same for KMAC, it's just that only one iteration is ever needed. Would this actually be more annoying from an implementer's point of view than just replacing prf+, though? The extra 0x01 is easy to forget if you simply redirect prf+ calls to KMAC instead. [I-D.smyslov-ipsecme-ikev2-prf-plus] suggests the alternative approach of replacing prf+ with a KMAC output of the required length. This could be simpler to implement, but does mean that if 128/256 bits are requested from prf+(K, S), these will be the same as prf(K, S), which isn't currently true for other PRFs in IKEv2. Use of context separators for prf and prf+ calls as suggested in this document would prevent that.¶
When KMAC is used in the prf+ construction, the customization string C is set to the ASCII character string "ikev2 kdf", without null termination.¶
IKE and IPsec SAs can make use of an integrity protection algorithm to provide data origin authentication and integrity protection services. KMAC can be used to provide these services. As described in [RFC8221], Authenticated Encryption with Associated Data (AEAD) ciphers are the fastest and most modern approach to providing these services in conjunction with confidentiality protection. KMAC MUST NOT be negotiated in IKEv2 in conjunction with an AEAD cipher.¶
KMAC MAY be used as an integrity protection algorithm with:¶
ESP in conjunction with a non-AEAD cipher¶
ESP and null encryption (ENCR_NULL)¶
IKEv2 in conjunction with a non-AEAD cipher¶
AH¶
EDNOTE: You really should use ENCR-NULL over AH here. RFC 8221 recommends use of ENCR_NULL over AH - would it be worth reiterating that here?¶
When using KMAC, the L input parameter is always set to the same value as the key size and security strength of the chosen KMAC algorithm. That is, the output length of KMAC128 is always set to 128 bits, and the output length of KMAC256 is always set to 256 bits.¶
When used with ESP or AH, the "customization string" parameter C is set to the ASCII character string "ipsec integ", without null termination. When used with IKEv2 for integrity protection, the "customization string" parameter C is set to the ASCII character string "ikev2 integ", without null termination.¶
EDNOTE: Again, the customization string differences probably aren't strictly necessary, but placing IPsec and IKEv2 integrity/prf/prf+ into different domains seems like a good thing to do.¶
SHAKE and the SHA-3 cryptographic hash functions can generate digests for use with signature algorithms. For instance, [RFC8692] specifies algorithm identifiers for using RSASSA-PSS and ECDSA with SHAKE, and NIST has assigned OIDs for using RSA PKCS #1 v1.5 signatures with SHA-3 [NISTOIDS].¶
[RFC7427] specifies the "Digital Signature" (14) authentication method, that allows IKEv2 to support any signature algorithm without the need to specify an authentication method for every new combination of signature algorithm and hash function. The Digital Signature authentication method is the only way to utilise SHA-3 with signatures in IKEv2, so if a peer uses SHA-3 in this context, it MUST specify the Digital Signature authentication method in its corresponding AUTH payload.¶
The Digital Signature authentication method specifies use of a SIGNATURE_HASH_ALGORITHMS notification by each IKEv2 peer to announce the hash functions it supports for use with signatures. This specification defines values in Table 7 for announcing support for SHA-3 algorithms in the SIGNATURE_HASH_ALGORITHMS notification. When an IKEv2 implementation supports SHA-3 in this context, and local policy permits use of SHA-3 to generate or verify signatures, it MUST include the corresponding values in its SIGNATURE_HASH_ALGORITHMS notification.¶
KMAC's API differs from most PRF and Integrity Algorithm transforms as described in Section 5. Care should be taken with the output length parameter L in particular, as its behavior can be counter-intuitive when compared to other integrity algorithms where a truncated output is used as an authenticator value. Unlike SHAKE, KMAC outputs of different lengths are not related. That is, the value of L is factored into the calculation of the output value, and thus all bits of the output value are affected. This means that implementations cannot simply discard a portion of a KMAC output as a substitute for requesting the correct value for L. For example, a KMAC256 implementation used as the PRF transform for IKEv2 cannot be used as an Integrity transform simply by discarding bits from that implementation's output; a different value of L must be supplied. Table 4 shows an example for the case where the key, input and (in the case of KMAC) customization string are all the empty string.¶
| Transform Name | Output Length (bits) | Output (hex) |
|---|---|---|
| PRF_HMAC_SHA2_256 | 256 | b613679a0814d9ec772f95d778c35fc5... |
| AUTH_HMAC_SHA2_256_128 | 128 | b613679a0814d9ec772f95d778c35fc5 |
| PRF_KMAC_128 | 256 | 5c135c615152fb4d9784dd1155f9b603... |
| AUTH_KMAC_128 | 128 | e6aff27fef95903eb939bc3745730d34 |
This is also true for prf+ when used with KMAC. Typically prf+ is used iteratively to obtain at least as much key material as is required, and the amount of key material obtained will be a multiple of the output size of the negotiated PRF. This process will often produce more key material than required, and the excess is simply discarded. When KMAC is used, the amount of key material required is supplied to the PRF, and exactly the right amount of key material will be returned. Requesting more key material than required and discarding any excess will produce different keys, and interoperability will not be possible.¶
Future authors of IPsec documents should be careful to consider whether related outputs from a PRF are required for their specification, and if so, describe how to handle KMAC and similar PRFs.¶
SHA-3 and SHA-2 are both believed to be secure at time of writing. Views on the security of cryptographic algorithms evolve over time, so implementers should pay attention to IETF RFCs reporting on recommendations for the use of cryptographic algorithms in IKEv2 and IPsec, such as any documents that update [RFC8221] and [RFC8247].¶
Quantum computing has a significant impact on the security of all IETF security protocols, as a cryptographically-relevant quantum computer (CRQC) could use Shor's algorithm to break many traditional asymmetric cryptographic algorithms. A CRQC can theoretically also attack hash functions, including SHA-3 and SHA-2, using Grover's algorithm. However, the impact of Grover's algorithm is significantly less dramatic than the impact of Shor's Algorithm. The worst-case impact of Grover's algorithm would be a reduction in security strength by a factor of two. However, since Grover's algorithm is difficult to parallelise, the security reduction for SHA-3 and SHA-2 caused by Grover's algorithm is expected to be far less significant in practice. See [GROVER] for a discussion on the practical cost of using Grover's algorithm to attack hash functions.¶
The security properties offered by KMAC depend on limiting access to the keys used with those algorithms. Since both algorithms depend on a symmetric key, the key must be known by at least two parties in order to be useful. Sharing the key beyond two parties may erode the security offered by these algorithms. In the case of IKEv2 and IPsec, this typically means that access to keys must be limited to the peers participating in the security association that uses those keys. IKEv2 can be used to enforce this for IPsec SAs and most keys used in IKE SAs, but pre-shared keys are a notable exception here. Providing more than two peers with access to a single pre-shared key may undermine the security offered by that pre-shared key, and hence the security offered by KMAC.¶
When IKEv2 is used to create IPsec SAs, the keys for KMAC are all ultimately derived from an ephemeral shared secret produced using one or more negotiated key exchange algorithms, with the exception of static pre-shared keys used in IKEv2 for authentication and/or protection against quantum computers. If the negotiated key exchange algorithm or encryption algorithm offers fewer bits of security than the negotiated PRF, this effectively caps the bits of security offered by the PRF as well. Negotiating a key exchange algorithm or encryption algorithm that offers more bits of security than the negotiated PRF does not improve the security offered by that PRF. As such, it is important to ensure that IKEv2 peers configure algorithm policies such that every algorithm negotiated always meets an acceptable minimum security strength. Where static keys are used with KMAC, these MUST contain at least as much entropy as the security strength of the chosen algorithm, and SHOULD be generated using a random number generator suitable for use with cryptography.¶
For negotiating use of KMAC as a PRF for IKEv2, IANA is requested to assign two Transform IDs in the "Transform Type 2 - Pseudorandom Function Transform IDs" registry:¶
| Number | Name | Status | Reference |
|---|---|---|---|
| TBD | PRF_KMAC_128 | [This draft] | |
| TBD | PRF_KMAC_256 | [This draft] |
For negotiating use of KMAC for integrity protection in IKEv2 and IPsec protocols, IANA is requested to assign two Transform IDs in the "Transform Type 3 - Integrity Algorithm Transform IDs" registry:¶
| Number | Name | Status | Reference |
|---|---|---|---|
| TBD | AUTH_KMAC_128 | [This draft] | |
| TBD | AUTH_KMAC_256 | [This draft] |
For indicating support for the SHA-3 cryptographic hash functions and SHAKE XOFs in conjunction with a signature algorithm, IANA is requested to assign five Transform IDs in the "IKEv2 Hash Algorithms" registry:¶
| Value | Hash Algorithm | Reference |
|---|---|---|
| TBD | SHA3_256 | [This draft] |
| TBD | SHA3_384 | [This draft] |
| TBD | SHA3_512 | [This draft] |
| TBD | SHAKE_128 | [This draft] |
| TBD | SHAKE_256 | [This draft] |
The following test cases include inputs and outputs for scenarios where KMAC is used in IKEv2 and IPsec.¶
A key, input, customization string, and output are always supplied. These correspond to the K, S, C, and Z parameters described in Section 5. Note that in each context, the customization string is fixed.¶
All inputs and outputs are encoded in hexadecimal. KMAC customization strings also have an ASCII character string representation. Data supplied to KMAC does not include quotation marks or null terminators.¶
In some cases a description is supplied, which describes the case being tested in more detail. These descriptions are test vector metadata, and are not ever supplied to the relevant algorithm.¶
These test cases correspond to use of KMAC as the PRF transform for an IKE SA.¶
~~ Test Case KMAC128-PRF-1 ~~ Description: Preferred key size Key (hex): 000102030405060708090a0b0c0d0e0f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 Customization String (string): "ikev2 prf" Customization String (hex): 696b65763220707266 Output (hex): 942d56a4597c0d104497dc1c62be940a70198b32bfde8e2a5f57f55ec3fe5cef ~~ Test Case KMAC128-PRF-2 ~~ Description: Smaller key size Key (hex): 0001020304050607 Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 Customization String (string): "ikev2 prf" Customization String (hex): 696b65763220707266 Output (hex): b050dd45ec09370cd2fe4b7c2a009618c5a426e81a4f11f6c538cf17027dbee3 ~~ Test Case KMAC128-PRF-3 ~~ Description: Larger key size Key (hex): 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 Customization String (string): "ikev2 prf" Customization String (hex): 696b65763220707266 Output (hex): 3a8d2a5ead5cd4db448b76a241b078fb444e1faf36eef8e195e275778a169b5f¶
~~ Test Case KMAC256-PRF-1 ~~ Description: Preferred key size Key (hex): 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 Customization String (string): "ikev2 prf" Customization String (hex): 696b65763220707266 Output (hex): 922d6a5ea665e5418974b218d84d3e9946163563e2208f33a4beac7091ae363c f54d998ff215d1a66357b8e3c5d8a083dfba20f4bfac697fcd134faf8db1c051 ~~ Test Case KMAC256-PRF-2 ~~ Description: Smaller key size Key (hex): 000102030405060708090a0b0c0d0e0f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 Customization String (string): "ikev2 prf" Customization String (hex): 696b65763220707266 Output (hex): 7379097e0e2812e4b9a342ffb68e1b50028e87536006cbcf3e4bbff74bdef6e5 86fd2cbfb3baf59f0c63969da28ba6506e826c1a74e045d9d511929b4d6bfb51 ~~ Test Case KMAC256-PRF-3 ~~ Description: Larger key size Key (hex): 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f 202122232425262728292a2b2c2d2e2f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 Customization String (string): "ikev2 prf" Customization String (hex): 696b65763220707266 Output (hex): 923efa870d85a6f31253f14c661d622951efcc729770dae1bd01cc8174fd27b6 93be6869aaeff4cb89d1a355629c2525555c959d39217c8a8b8d0a7420eed96c¶
These test cases correspond to use of KMAC with IKEv2's prf+ function.¶
~~ Test Case KMAC128-KDF-1 ~~ Description: IKEv2 KDF request single PRF output Key (hex): 000102030405060708090a0b0c0d0e0f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 Number of output bits requested (integer): 256 Customization String (string): "ikev2 kdf" Customization String (hex): 696b657632206b6466 Output (hex): 8226d67fdc4d2cc013a401461d21d6f17b4121f3a300972f6b163c8e4a4192be ~~ Test Case KMAC128-KDF-2 ~~ Description: IKEv2 KDF request multiple PRF output Key (hex): 000102030405060708090a0b0c0d0e0f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 Number of output bits requested (integer): 512 Customization String (string): "ikev2 kdf" Customization String (hex): 696b657632206b6466 Output (hex): ea9f5defe875dcdc9c1b4db30bb1950f21838601af2e1f8f41beefe18e7b779c 2a25ae188d6cafc6546574110c94d8b0a67740ed63ba5dfb07316b1473498156 ~~ Test Case KMAC128-KDF-3 ~~ Description: IKE SA key material ENCR=ENCR_AES_GCM_16 with 128-bit key PRF=PRF_KMAC_128 SK_d = 128 bits SK_a[i|r] = nil SK_e[i|r] = 160*2 bits SK_p[i|r] = 128*2 bits Key (hex): 000102030405060708090a0b0c0d0e0f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 dfdedddcdbdad9d8d7d6d5d4d3d2d1d0 Number of output bits requested (integer): 704 Customization String (string): "ikev2 kdf" Customization String (hex): 696b657632206b6466 Output (hex): 6be4bbda1483209cb64de61c306ebc8b0357ff661f419b298eb8f78deb6a47a4 5a5a1d16bc00e46926e04cd53d4d843d4d2526cf275c3422d08aab7c610ff88d 11a50de2e6c021dde966c18111d40c6e57a798e8ce13a007 ~~ Test Case KMAC128-KDF-4 ~~ Description: IKE SA key material ENCR=ENCR_AES_CBC with 128-bit key INTEG=AUTH_KMAC_128 PRF=PRF_KMAC_128 SK_d = 128 bits SK_a[i|r] = 128*2 bits SK_e[i|r] = 128*2 bits SK_p[i|r] = 128*2 bits Key (hex): 000102030405060708090a0b0c0d0e0f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 dfdedddcdbdad9d8d7d6d5d4d3d2d1d0 Number of output bits requested (integer): 896 Customization String (string): "ikev2 kdf" Customization String (hex): 696b657632206b6466 Output (hex): 3ef21c2736e603449ca86869be92ff6a4a116198a69364950456a0b3ee0fb63c 98e20830e703a8f1ee9a7b2c39ad19410b6e2b97026b408b706c4c393304710f 961f55d1e7fc8805ebb5c6190db0f8f2d47032e3f12115156fa5296d7afc6d1e cf6af577aeeaa289f0a2b73287637ff9 ~~ Test Case KMAC128-KDF-5 ~~ Description: ESP key material ENCR=ENCR_AES_CBC with 128-bit key INTEG=AUTH_KMAC_128 KEYMAT=(128*2) + (128*2) bits Key (hex): 000102030405060708090a0b0c0d0e0f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 Number of output bits requested (integer): 512 Customization String (string): "ikev2 kdf" Customization String (hex): 696b657632206b6466 Output (hex): ea9f5defe875dcdc9c1b4db30bb1950f21838601af2e1f8f41beefe18e7b779c 2a25ae188d6cafc6546574110c94d8b0a67740ed63ba5dfb07316b1473498156¶
~~ Test Case KMAC256-KDF-1 ~~ Description: IKEv2 KDF request single PRF output Key (hex): 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 Number of output bits requested (integer): 512 Customization String (string): "ikev2 kdf" Customization String (hex): 696b657632206b6466 Output (hex): cf0a2cca4eb61bf2f2d1c840e445f8f83da66c5a04603b67c4f5e5421ea7df56 28ffae929fbaa418af3fb1982873359d85e550e31f8d23893d3db1cf2652e353 ~~ Test Case KMAC256-KDF-2 ~~ Description: IKEv2 KDF request multiple PRF output Key (hex): 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 Number of output bits requested (integer): 1024 Customization String (string): "ikev2 kdf" Customization String (hex): 696b657632206b6466 Output (hex): 977a3b6d7ca5350b715330312375f5e291738dbd87504493b521164cd82ed09c 83f955d3a9475902809e20cf9217addb49126fff9e3bde68f7b7062ff336a69f aae8cb5b3486870031f9bc4df5bcda12384bfb096f67953c93c2eeb0a62a0353 728f8e2227c1f6c750207e75ccbecf0a25640f2d24795d4a83b3cf482721d249 ~~ Test Case KMAC256-KDF-3 ~~ Description: IKE SA key material ENCR=ENCR_AES_GCM_16 with 256-bit key PRF=PRF_KMAC_256 SK_d = 256 bits SK_a[i|r] = nil SK_e[i|r] = 288*2 bits SK_p[i|r] = 256*2 bits Key (hex): 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 dfdedddcdbdad9d8d7d6d5d4d3d2d1d0 Number of output bits requested (integer): 1344 Customization String (string): "ikev2 kdf" Customization String (hex): 696b657632206b6466 Output (hex): 67c1d3627a0249c0722646ae7904b376a41ee36bdd8beceed7d7a2651610fae6 cdd494f7e46b8a9ec531c9f8849960b98d938a021960b40bec88103d24a166a4 5d7c09fc52b8071ca129f29f3d0ce0b8e923424618c4e0b361e142efd154ebdd 65e344509c44b8ed082a8ec3d11aa32b0d9968013c9071d9a99d748710fcfb5a 974ff991216239cc639b2be413d08e7097225eb1c0eb642584eac86f7923a199 e59a008352f6cf70 ~~ Test Case KMAC256-KDF-4 ~~ Description: IKE SA key material ENCR=ENCR_AES_CBC with 256-bit key INTEG=AUTH_KMAC_256 PRF=PRF_KMAC_256 SK_d = 256 bits SK_a[i|r] = 256*2 bits SK_e[i|r] = 256*2 bits SK_p[i|r] = 256*2 bits Key (hex): 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 dfdedddcdbdad9d8d7d6d5d4d3d2d1d0 Number of output bits requested (integer): 1792 Customization String (string): "ikev2 kdf" Customization String (hex): 696b657632206b6466 Output (hex): 836772bd1139dc8e5fa303e4cff1d75ad3a9c699335a5bfba6de4900e0072cb1 6a66260202ee96c51d14e8b335f9a683d18d703770be23658d74942d15ac1393 f84f849081505f95e69a18123552d12497f59032d6fa5bf2b8c35bd788dc4f60 a1f47e3859163c8929a8cc11c2103f2507549d4e78ad5848eec92271522b5607 38bb30ed7a90070124e685f41929c750a8ccfc1d8fe4288e701e316ed0e25852 0609d157ef05d99efe3db9f9b3ce042c87b8e37dfe194ff4df4b4ff5a07aa56b e6bbc2470e5b6fc72177596064bb48c63e6730737aff6f6d32ed28d64dd37d3b ~~ Test Case KMAC256-KDF-5 ~~ Description: ESP key material ENCR=ENCR_AES_CBC with 256-bit key INTEG=AUTH_KMAC_256 KEYMAT=(256*2) + (256*2) bits Key (hex): 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 Number of output bits requested (integer): 1024 Customization String (string): "ikev2 kdf" Customization String (hex): 696b657632206b6466 Output (hex): 977a3b6d7ca5350b715330312375f5e291738dbd87504493b521164cd82ed09c 83f955d3a9475902809e20cf9217addb49126fff9e3bde68f7b7062ff336a69f aae8cb5b3486870031f9bc4df5bcda12384bfb096f67953c93c2eeb0a62a0353 728f8e2227c1f6c750207e75ccbecf0a25640f2d24795d4a83b3cf482721d249¶
These test cases correspond to use of KMAC as the integrity protection transform for an IKE SA. Note that, since different customization strings are used for integrity protection in IKEv2 and IPsec, different outputs are produced, so two sets of test vectors are supplied.¶
~~ Test Case KMAC128-IKEV2-INTEG-1 ~~ Key (hex): 000102030405060708090a0b0c0d0e0f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 Customization String (string): "ikev2 integ" Customization String (hex): 696b65763220696e746567 Output (hex): 4d75b6e6bdf3021df40241b9ecc083e8¶
~~ Test Case KMAC256-IKEV2-INTEG-1 ~~ Key (hex): 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 Customization String (string): "ikev2 integ" Customization String (hex): 696b65763220696e746567 Output (hex): d4e085d2434827192490ea96a205c24a8a471417e8d7bdbb33a76f7a2e9bbe54¶
These test cases correspond to use of KMAC as the integrity protection transform for an IPsec SA. Note that, since different customization strings are used for integrity protection in IKEv2 and IPsec, different outputs are produced, so two sets of test vectors are supplied.¶
~~ Test Case KMAC128-IPSEC-INTEG-1 ~~ Key (hex): 000102030405060708090a0b0c0d0e0f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 Customization String (string): "ipsec integ" Customization String (hex): 697073656320696e746567 Output (hex): cb53465b0191416d555424f155a48079¶
~~ Test Case KMAC256-IPSEC-INTEG-1 ~~ Key (hex): 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f Input (hex): fffefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0 Customization String (string): "ipsec integ" Customization String (hex): 697073656320696e746567 Output (hex): 2c890f94cb12e2b90fa9f8b3ea5ce53be91f1540619ae33dcc021083e9069e86¶