diff --git a/security/keymint/aidl/android/hardware/security/keymint/IKeyMintDevice.aidl b/security/keymint/aidl/android/hardware/security/keymint/IKeyMintDevice.aidl
index b9694e9..2caa4d5 100644
--- a/security/keymint/aidl/android/hardware/security/keymint/IKeyMintDevice.aidl
+++ b/security/keymint/aidl/android/hardware/security/keymint/IKeyMintDevice.aidl
@@ -336,6 +336,17 @@
      * Only Tag::KEY_SIZE is required to generate an 3DES key, and its value must be 168.  If
      * omitted, generateKey must return ErrorCode::UNSUPPORTED_KEY_SIZE.
      *
+     * == HMAC Keys ==
+     *
+     * Tag::KEY_SIZE must be provided to generate an HMAC key, and its value must be >= 64 and a
+     * multiple of 8.  All devices must support key sizes up to 512 bits, but StrongBox devices must
+     * not support key sizes larger than 512 bits.  If omitted or invalid, generateKey() must return
+     * ErrorCode::UNSUPPORTED_KEY_SIZE.
+     *
+     * Tag::MIN_MAC_LENGTH must be provided, and must be a multiple of 8 in the range 64 to 512
+     * bits (inclusive). If omitted, generateKey must return ErrorCode::MISSING_MIN_MAC_LENGTH; if
+     * invalid, generateKey must return ErrorCode::UNSUPPORTED_MIN_MAC_LENGTH.
+     *
      * @param keyParams Key generation parameters are defined as KeyMintDevice tag/value pairs,
      *        provided in params.  See above for detailed specifications of which tags are required
      *        for which types of keys.
@@ -661,19 +672,19 @@
      *   structure, because it cannot add the DigestInfo structure.  Instead, the IKeyMintDevice
      *   must construct 0x00 || 0x01 || PS || 0x00 || M, where M is the provided message and PS is a
      *   random padding string at least eight bytes in length.  The size of the RSA key has to be at
-     *   least 11 bytes larger than the message, otherwise begin() must return
+     *   least 11 bytes larger than the message, otherwise finish() must return
      *   ErrorCode::INVALID_INPUT_LENGTH.
      *
      * o PaddingMode::RSA_PKCS1_1_1_5_ENCRYPT padding does not require a digest.
      *
-     * o PaddingMode::RSA_PSS padding requires a digest, which must match one of the padding values
+     * o PaddingMode::RSA_PSS padding requires a digest, which must match one of the digest values
      *   in the key authorizations, and which may not be Digest::NONE.  begin() must return
      *   ErrorCode::INCOMPATIBLE_DIGEST if this is not the case.  In addition, the size of the RSA
-     *   key must be at least 2 + D bytes larger than the output size of the digest, where D is the
-     *   size of the digest, in bytes.  Otherwise begin() must return
-     *   ErrorCode::INCOMPATIBLE_DIGEST.  The salt size must be D.
+     *   key must be at least (D + S + 9) bits, where D is the size of the digest (in bits) and
+     *   S is the size of the salt (in bits).  The salt size S must equal D, so the RSA key must
+     *   be at least (2*D + 9) bits. Otherwise begin() must return ErrorCode::INCOMPATIBLE_DIGEST.
      *
-     * o PaddingMode::RSA_OAEP padding requires a digest, which must match one of the padding values
+     * o PaddingMode::RSA_OAEP padding requires a digest, which must match one of the digest values
      *   in the key authorizations, and which may not be Digest::NONE.  begin() must return
      *   ErrorCode::INCOMPATIBLE_DIGEST if this is not the case.  RSA_OAEP padding also requires an
      *   MGF1 digest, specified with Tag::RSA_OAEP_MGF_DIGEST, which must match one of the MGF1
@@ -683,9 +694,9 @@
      *
      * -- EC Keys --
      *
-     * Private key operations (KeyPurpose::SIGN) need authorization of digest and padding, which
-     * means that the key authorizations must contain the specified values.  If not, begin() must
-     * return ErrorCode::INCOMPATIBLE_DIGEST.
+     * Private key operations (KeyPurpose::SIGN) need authorization of digest, which means that the
+     * key authorizations must contain the specified values.  If not, begin() must return
+     * ErrorCode::INCOMPATIBLE_DIGEST.
      *
      * -- AES Keys --
      *
diff --git a/security/keymint/aidl/android/hardware/security/keymint/KeyPurpose.aidl b/security/keymint/aidl/android/hardware/security/keymint/KeyPurpose.aidl
index fd103ef..32e71a7 100644
--- a/security/keymint/aidl/android/hardware/security/keymint/KeyPurpose.aidl
+++ b/security/keymint/aidl/android/hardware/security/keymint/KeyPurpose.aidl
@@ -23,7 +23,7 @@
 @VintfStability
 @Backing(type="int")
 enum KeyPurpose {
-    /* Usable with RSA, 3DES and AES keys. */
+    /* Usable with 3DES and AES keys. */
     ENCRYPT = 0,
 
     /* Usable with RSA, 3DES and AES keys. */
@@ -32,7 +32,7 @@
     /* Usable with RSA, EC and HMAC keys. */
     SIGN = 2,
 
-    /* Usable with RSA, EC and HMAC keys. */
+    /* Usable with HMAC keys. */
     VERIFY = 3,
 
     /* 4 is reserved */
diff --git a/security/keymint/aidl/android/hardware/security/keymint/PaddingMode.aidl b/security/keymint/aidl/android/hardware/security/keymint/PaddingMode.aidl
index e71a9c9..6ff4b29 100644
--- a/security/keymint/aidl/android/hardware/security/keymint/PaddingMode.aidl
+++ b/security/keymint/aidl/android/hardware/security/keymint/PaddingMode.aidl
@@ -26,7 +26,7 @@
 @VintfStability
 @Backing(type="int")
 enum PaddingMode {
-    NONE = 1, /* deprecated */
+    NONE = 1,
     RSA_OAEP = 2,
     RSA_PSS = 3,
     RSA_PKCS1_1_5_ENCRYPT = 4,
diff --git a/security/keymint/aidl/android/hardware/security/keymint/Tag.aidl b/security/keymint/aidl/android/hardware/security/keymint/Tag.aidl
index 42dfad5..871a1ac 100644
--- a/security/keymint/aidl/android/hardware/security/keymint/Tag.aidl
+++ b/security/keymint/aidl/android/hardware/security/keymint/Tag.aidl
@@ -186,10 +186,16 @@
      * Tag::RSA_OAEP_MGF_DIGEST specifies the MGF1 digest algorithms that may be used with RSA
      * encryption/decryption with OAEP padding.  Possible values are defined by the Digest enum.
      *
-     * This tag is repeatable for key generation/import.  RSA cipher operations with OAEP padding
-     * must specify an MGF1 digest in the params argument of begin(). If this tag is missing or the
-     * specified digest is not in the MGF1 digests associated with the key then begin operation must
-     * fail with ErrorCode::INCOMPATIBLE_MGF_DIGEST.
+     * This tag is repeatable for key generation/import.
+     *
+     * If the caller specifies an MGF1 digest in the params argument of begin(), that digest must be
+     * present as an RSA_OAEP_MGF_DIGEST value in the key characteristics (or the begin() operation
+     * must fail with ErrorCode::INCOMPATIBLE_MGF_DIGEST).
+     *
+     * If the caller does not specify an MGF1 digest in the params argument of begin(), a default
+     * MGF1 digest of SHA1 is used.  If the key characteristics have any explicitly specified values
+     * for RSA_OAEP_MGF_DIGEST, then SHA1 must be included (or the begin() operation must fail with
+     * ErrorCode::INCOMPATIBLE_MGF_DIGEST).
      *
      * Must be hardware-enforced.
      */
diff --git a/security/sharedsecret/aidl/android/hardware/security/sharedsecret/SharedSecretParameters.aidl b/security/sharedsecret/aidl/android/hardware/security/sharedsecret/SharedSecretParameters.aidl
index 8144699..b72f0de 100644
--- a/security/sharedsecret/aidl/android/hardware/security/sharedsecret/SharedSecretParameters.aidl
+++ b/security/sharedsecret/aidl/android/hardware/security/sharedsecret/SharedSecretParameters.aidl
@@ -33,9 +33,9 @@
     byte[] seed;
 
     /**
-     * A 32-byte value which is guaranteed to be different each time
-     * getSharedSecretParameters() is called.  Probabilistic uniqueness (i.e. random) is acceptable,
-     * though a stronger uniqueness guarantee (e.g. counter) is recommended where possible.
+     * A 32-byte value which is guaranteed to be different each time getSharedSecretParameters() is
+     * called after a restart.  Probabilistic uniqueness (i.e. random) is acceptable, though a
+     * stronger uniqueness guarantee (e.g. counter) is recommended where possible.
      */
     byte[] nonce;
 }