diff --git a/draft-ietf-privacypass-auth-scheme.md b/draft-ietf-privacypass-auth-scheme.md
index 858ae954..d7b1f294 100644
--- a/draft-ietf-privacypass-auth-scheme.md
+++ b/draft-ietf-privacypass-auth-scheme.md
@@ -536,7 +536,7 @@ to overwhelm issuance servers. The limits here will vary based on the specific
 deployment, but clients SHOULD have some implementation-specific policy
 to minimize the number of tokens that can be retrieved by origins.
 
-## Choosing Between Multiple Challenges
+## Choosing Between Multiple Challenges {#choosing-between-multiple-challenges}
 
 A single response from an origin can include multiple token challenges.
 For example, a set of challenges could include different token types
@@ -852,6 +852,7 @@ configurations:
 3. TokenChallenge with an empty origin and redemption context
 4. TokenChallenge with an empty origin and non-empty redemption context
 5. TokenChallenge with a multiple origins and non-empty redemption context
+6. TokenChallenge for greasing
 
 These test vectors are below.
 
@@ -939,16 +940,32 @@ token_authenticator_input: 0002e01978182c469e5e026d66558ee1865686
 14f235e41ef7e2378e6f202688ababa2a775866b6ae0f98944910c8f48728d8a2
 735b9157762ddbf803f70e2e8ba3eca572f8982a9ca248a3056186322d93ca147
 266121ddeb5632c07f1f71cd2708
+
+// Test vector 6:
+//   token_type(0000), structure(random_bytes)
+token_type: 0000
+token_authenticator_input: 000058405ad31e286e874cb42d0ef9d50461ae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 ~~~
 
 ## HTTP Header Test Vectors
 
 This section includes test vectors the contents of the HTTP authentication
 headers. Each test vector consists of one or more challenges that comprise
-a WWW-Authenticate header. For each challenge, the token-type, token-key,
-max-age, and token-challenge parameters are listed. Each challenge also
-includes an unknown (not specified) parameter that implementations are meant
-to ignore.
+a WWW-Authenticate header, as defined in {(choosing-between-multiple-challenges}}.
+For each challenge, the token-type, token-key, max-age, and token-challenge
+parameters are listed. Each challenge also includes an unknown (not specified)
+parameter that implementations are meant to ignore.
 
 The parameters for each challenge are indexed by their position
 in the WWW-Authentication challenge list. For example, token-key-0 denotes
@@ -960,6 +977,9 @@ list of challenges is then listed at the end. Line folding is only
 used to fit the document formatting constraints and not supported
 in actual requests.
 
+The last challenge on this list include Basic authentication, as well as a
+greasing challenge. Both MUST be ignored by client implementation.
+
 ~~~
 token-type-0: 0x0002
 token-key-0: 30820152303d06092a864886f70d01010a3030a00d300b060960864
@@ -1027,4 +1047,30 @@ e="AAEADmlzc3Vlci5leGFtcGxlIIo-g6M9mABdLzC-9Bn6a_TNXGAF42sShbu0zNQPp
 LODAA5vcmlnaW4uZXhhbXBsZQ==", token-key="67H-0zgxA2HAjQx1dpaWcSluBem
 aF9eSbfwopT-r1In6wPgryoYkmmaPOlv6s3TJ",unknownChallengeAttribute="ig
 nore-me", max-age="10"
+
+token-type-0: 0x0000
+token-key-0: 856de3c710b892e7cca1ae5eb121af42ca8e779137a11224228c9b9
+9b0729bf84d5057d030000309b8f0d06ccffa17561f9eacd4c312e985a6bc60ffbea
+0610264dcb1726255313da81d665692686a1d8644f1516bf612cea009e6dff6d9a9a
+959fb538e1b5b2343c092992942382bdde22d5b324b1e4618ed21d7806286c2ce
+token-challenge-0: 0000acc3b25795c636fd9dd8b12982394abba8777d35978e8
+77fc8848892a217233045ac25a3d55c07c54efe6372973fee0073e77fc61bf19ab88
+0f20edf5d627502
+token-type-1: 0x0001
+token-key-1: ebb1fed338310361c08d0c7576969671296e05e99a17d7926dfc28a
+53fabd489fac0f82bca86249a668f3a5bfab374c9
+max-age-1: 10
+token-challenge-1: 0001000e6973737565722e6578616d706c65208a3e83a33d9
+8005d2f30bef419fa6bf4cd5c6005e36b1285bbb4ccd40fa4b383000e6f726967696
+e2e6578616d706c65
+
+WWW-Authenticate: Basic realm="grease", PrivateToken challenge="AACs
+w7JXlcY2_Z3YsSmCOUq7qHd9NZeOh3_IhIiSohcjMEWsJaPVXAfFTv5jcpc_7gBz53_G
+G_GauIDyDt9dYnUC",token-key="hW3jxxC4kufMoa5esSGvQsqOd5E3oRIkIoybmbB
+ym_hNUFfQMAADCbjw0GzP-hdWH56s1MMS6YWmvGD_vqBhAmTcsXJiVTE9qB1mVpJoah2
+GRPFRa_YSzqAJ5t_22ampWftTjhtbI0PAkpkpQjgr3eItWzJLHkYY7SHXgGKGws4=",
+PrivateToken challenge="AAEADmlzc3Vlci5leGFtcGxlIIo-g6M9mABdLzC-9Bn6
+a_TNXGAF42sShbu0zNQPpLODAA5vcmlnaW4uZXhhbXBsZQ==", token-key="67H-0z
+gxA2HAjQx1dpaWcSluBemaF9eSbfwopT-r1In6wPgryoYkmmaPOlv6s3TJ",unknownC
+hallengeAttribute="ignore-me", max-age="10"
 ~~~