diff --git a/README.md b/README.md
index f6e1212ef..6f0286399 100644
--- a/README.md
+++ b/README.md
@@ -72,6 +72,30 @@ $ cardano-address key public --with-chain-code < acct.xsk | cardano-address key
 ```
 </details>
 
+<details>
+  <summary>How to generate a private policy key (<strong>policy.xsk</strong>), a public policy key (<strong>policy.vk</strong>) and its hash (<strong>policy.vkh</strong>)</summary>
+
+```console
+$ cardano-address key child 1855H/1815H/0H < root.xsk > policy.xsk
+policy_xsk1hr47zvxgzeeutgq50r965ygwxys86cwp8wdjqftlhan8mw6849pus6vc50dznjs5vkyjcz9usl6964u6nha88slrh8hyex74xnlfehcrkp80cp8wgzkqh22dzy7c48ekhhvvf2zz8hqakjwgfzgrjq5lx538et75
+
+$ cardano-address key child 1855H/1815H/0H < root.xsk | cardano-address key public --with-chain-code > policy.xvk
+policy_xvk1e9ngmlhcwhszwyuxwc7anwk6tvzwndldz7j262rvfpd049tq74mq8vzwlszwus9vpw556yfa320nd0wccj5yy0wpmdyusjys8ypf7dgaauf0m
+
+$ cardano-address key child 1855H/1815H/0H < root.xsk | cardano-address key public --without-chain-code > policy.vk
+policy_vk1e9ngmlhcwhszwyuxwc7anwk6tvzwndldz7j262rvfpd049tq74mq0ylkrs
+
+$ cardano-address key hash < policy.xvk
+policy_vkh1qpc9xly4lc7yt98gcf59kdcqcss6dda4u9g72e775yxpxeypamc
+$ cardano-address key hash < policy.vk
+policy_vkh1qpc9xly4lc7yt98gcf59kdcqcss6dda4u9g72e775yxpxeypamc
+$ cardano-address key hash --hex < policy.vk
+0070537c95fe3c4594e8c2685b3700c421a6b7b5e151e567dea10c13
+```
+
+> :information_source: The last segment in the path is the key index and can be incremented up to `2^31-1` to derive more keys.
+</details>
+
 
 <details>
   <summary>How to generate a payment verification key (<strong>addr.xvk</strong>)</summary>
diff --git a/command-line/lib/Command/Key/Child.hs b/command-line/lib/Command/Key/Child.hs
index 7ab6a37c1..f7b49034f 100644
--- a/command-line/lib/Command/Key/Child.hs
+++ b/command-line/lib/Command/Key/Child.hs
@@ -166,6 +166,9 @@ run Child{path} = do
               -- 2147485502 stands for 1854H
               if p == 2147485502 then
                   pure CIP5.acct_shared_xsk
+              -- 2147485503 stands for 1855H
+              else if p == 2147485503 then
+                  pure CIP5.policy_xsk
               else
                   pure CIP5.acct_xsk
         | hrp == CIP5.root_shared_xsk = pure CIP5.acct_shared_xsk
diff --git a/command-line/lib/Command/Key/Hash.hs b/command-line/lib/Command/Key/Hash.hs
index 792dd8cb4..a4528325f 100644
--- a/command-line/lib/Command/Key/Hash.hs
+++ b/command-line/lib/Command/Key/Hash.hs
@@ -71,12 +71,14 @@ run Hash{outputFormat} = do
         , ( CIP5.addr_shared_xvk , CIP5.addr_shared_vkh )
         , ( CIP5.stake_shared_vk , CIP5.stake_shared_vkh )
         , ( CIP5.stake_shared_xvk, CIP5.stake_shared_vkh )
+        , ( CIP5.policy_vk       , CIP5.policy_vkh  )
+        , ( CIP5.policy_xvk      , CIP5.policy_vkh  )
         ]
     allowedPrefixes = map fst prefixes
     prefixFor = fromJust . flip lookup prefixes
 
     guardBytes hrp bytes
-        | hrp `elem` [CIP5.addr_xvk, CIP5.stake_xvk, CIP5.addr_shared_xvk, CIP5.stake_shared_xvk] = do
+        | hrp `elem` [CIP5.addr_xvk, CIP5.stake_xvk, CIP5.addr_shared_xvk, CIP5.stake_shared_xvk, CIP5.policy_xvk] = do
             when (BS.length bytes /= 64) $
                 fail "data should be a 32-byte public key with a 32-byte chain-code appended"
 
diff --git a/command-line/lib/Command/Key/Inspect.hs b/command-line/lib/Command/Key/Inspect.hs
index 087b5eb85..1c23c7a22 100644
--- a/command-line/lib/Command/Key/Inspect.hs
+++ b/command-line/lib/Command/Key/Inspect.hs
@@ -67,6 +67,8 @@ run Inspect = do
         , CIP5.addr_xsk
         , CIP5.stake_xvk
         , CIP5.stake_xsk
+        , CIP5.policy_xvk
+        , CIP5.policy_xsk
         , CIP5.root_shared_xvk
         , CIP5.root_shared_xsk
         , CIP5.acct_shared_xvk
diff --git a/command-line/lib/Command/Key/Public.hs b/command-line/lib/Command/Key/Public.hs
index 20bbcf57e..d960bcd82 100644
--- a/command-line/lib/Command/Key/Public.hs
+++ b/command-line/lib/Command/Key/Public.hs
@@ -67,6 +67,7 @@ run Public{chainCode} = do
         , (CIP5.acct_shared_xsk, (CIP5.acct_shared_xvk, CIP5.acct_shared_vk) )
         , (CIP5.addr_shared_xsk, (CIP5.addr_shared_xvk, CIP5.addr_shared_vk) )
         , (CIP5.stake_shared_xsk, (CIP5.stake_shared_xvk, CIP5.stake_shared_vk) )
+        , (CIP5.policy_xsk, (CIP5.policy_xvk, CIP5.policy_vk) )
         ]
     allowedPrefixes = map fst prefixes
     getCC WithChainCode = fst
diff --git a/command-line/test/Command/Key/ChildSpec.hs b/command-line/test/Command/Key/ChildSpec.hs
index f97a01878..c7eaee0a0 100644
--- a/command-line/test/Command/Key/ChildSpec.hs
+++ b/command-line/test/Command/Key/ChildSpec.hs
@@ -22,6 +22,7 @@ spec = describeCmd [ "key", "child" ] $ do
     specChildValidPath "addr_shared_xsk" ["1854H/1815H/0H/0/0"]
     specChildValidPath "addr_shared_xsk" ["1854H/1815H/0H", "0/0"]
     specChildValidPath "addr_xsk" ["14H/42H"]
+    specChildValidPath "policy_xsk" ["1855H/1815H/0H"]
 
     specChildInvalidPath "from a parent root key" ["0H"]
     specChildInvalidPath "from a parent account key" ["1852H/1815H/0H", "0H"]
diff --git a/command-line/test/Command/Key/HashSpec.hs b/command-line/test/Command/Key/HashSpec.hs
index 4d7021037..d7b20bc34 100644
--- a/command-line/test/Command/Key/HashSpec.hs
+++ b/command-line/test/Command/Key/HashSpec.hs
@@ -26,6 +26,9 @@ spec = describeCmd [ "key", "hash" ] $ do
     specKeyPublic "shared" "addr_shared_vkh"   "1854H/1815H/0H/0/0" "--with-chain-code"
     specKeyPublic "shared" "stake_shared_vkh"  "1854H/1815H/0H/2/0" "--with-chain-code"
 
+    specKeyPublic "shelley" "policy_vkh"   "1855H/1815H/0H" "--with-chain-code"
+    specKeyPublic "shelley" "policy_vkh"   "1855H/1815H/0H" "--without-chain-code"
+
 specKeyNotPublic :: SpecWith ()
 specKeyNotPublic = it "fail if key isn't public" $ do
     (out, err) <- cli [ "recovery-phrase", "generate" ] ""
diff --git a/command-line/test/Command/Key/InspectSpec.hs b/command-line/test/Command/Key/InspectSpec.hs
index c0ef26fad..abf724cd7 100644
--- a/command-line/test/Command/Key/InspectSpec.hs
+++ b/command-line/test/Command/Key/InspectSpec.hs
@@ -44,11 +44,13 @@ spec = describeCmd [ "key", "inspect" ] $ do
     specInspectPrivate CIP5.acct_shared_xsk
     specInspectPrivate CIP5.addr_shared_xsk
     specInspectPrivate CIP5.stake_shared_xsk
+    specInspectPrivate CIP5.policy_xsk
 
     specInspectPublic CIP5.root_xvk
     specInspectPublic CIP5.acct_xvk
     specInspectPublic CIP5.addr_xvk
     specInspectPublic CIP5.stake_xvk
+    specInspectPublic CIP5.policy_xvk
     specInspectPublic CIP5.root_shared_xvk
     specInspectPublic CIP5.acct_shared_xvk
     specInspectPublic CIP5.addr_shared_xvk
diff --git a/core/lib/Cardano/Address/Derivation.hs b/core/lib/Cardano/Address/Derivation.hs
index e7f3552b8..faaa94950 100644
--- a/core/lib/Cardano/Address/Derivation.hs
+++ b/core/lib/Cardano/Address/Derivation.hs
@@ -324,7 +324,7 @@ credentialHashSize = hashDigestSize Blake2b_224
 -- are no constructors for these.
 --
 -- @since 1.0.0
-data Depth = RootK | AccountK | PaymentK | DelegationK | ScriptK
+data Depth = RootK | AccountK | PaymentK | DelegationK | ScriptK | PolicyK
 
 -- | A derivation index, with phantom-types to disambiguate derivation type.
 --
diff --git a/core/lib/Cardano/Address/Script.hs b/core/lib/Cardano/Address/Script.hs
index eca54f534..050871ff2 100644
--- a/core/lib/Cardano/Address/Script.hs
+++ b/core/lib/Cardano/Address/Script.hs
@@ -216,7 +216,7 @@ scriptHashFromBytes bytes
     | BS.length bytes /= credentialHashSize = Nothing
     | otherwise = Just $ ScriptHash bytes
 
-data KeyRole = Payment | Delegation
+data KeyRole = Payment | Delegation | Policy
     deriving (Generic, Show, Ord, Eq)
 instance NFData KeyRole
 
@@ -247,15 +247,20 @@ keyHashToText (KeyHash cred keyHash) = case cred of
         T.decodeUtf8 $ encode (EBech32 CIP5.addr_shared_vkh) keyHash
     Delegation ->
         T.decodeUtf8 $ encode (EBech32 CIP5.stake_shared_vkh) keyHash
+    Policy ->
+        T.decodeUtf8 $ encode (EBech32 CIP5.policy_vkh) keyHash
 
 -- | Construct a 'KeyHash' from 'Text'. It should be
 -- Bech32 encoded text with one of following hrp:
 -- - `addr_shared_vkh`
 -- - `stake_shared_vkh`
+-- - `policy_vkh`
 -- - `addr_shared_vk`
 -- - `stake_shared_vk`
 -- - `addr_shared_xvk`
 -- - `stake_shared_xvk`
+-- - `policy_vk`
+-- - `policy_xvk`
 -- Raw keys will be hashed on the fly, whereas hash that are directly
 -- provided will remain as such.
 --
@@ -272,10 +277,13 @@ keyHashFromText txt = do
     convertBytes hrp bytes
         | hrp == CIP5.addr_shared_vkh  = Just (Payment, bytes)
         | hrp == CIP5.stake_shared_vkh = Just (Delegation, bytes)
+        | hrp == CIP5.policy_vkh       = Just (Policy, bytes)
         | hrp == CIP5.addr_shared_vk   = Just (Payment, hashCredential bytes)
         | hrp == CIP5.addr_shared_xvk  = Just (Payment, hashCredential $ BS.take 32 bytes)
         | hrp == CIP5.stake_shared_vk  = Just (Delegation, hashCredential bytes)
         | hrp == CIP5.stake_shared_xvk = Just (Delegation, hashCredential $ BS.take 32 bytes)
+        | hrp == CIP5.policy_vk        = Just (Policy, hashCredential bytes)
+        | hrp == CIP5.policy_xvk       = Just (Policy, hashCredential $ BS.take 32 bytes)
         | otherwise                    = Nothing
 
 -- Validation level. Required level does basic check that will make sure the script
@@ -307,7 +315,7 @@ prettyErrKeyHashFromText = \case
     ErrKeyHashFromTextWrongPayload ->
         "Verification key hash must contain exactly 28 bytes."
     ErrKeyHashFromTextWrongHrp ->
-        "Invalid human-readable prefix: must be 'script_vkh'."
+        "Invalid human-readable prefix: must be 'X_vkh', 'X_vk', 'X_xvk' where X is 'addr_shared', 'stake_shared' or 'policy'."
     ErrKeyHashFromTextWrongDataPart ->
         "Verification key hash is Bech32-encoded but has an invalid data part."
 
@@ -534,7 +542,8 @@ prettyErrValidateScript = \case
         "All keys of a script must have the same role: either payment or delegation."
     Malformed ->
         "Parsing of the script failed. The script should be composed of nested \
-        \lists, the verification keys should be bech32-encoded with prefix 'script_vhk', \
+        \lists, the verification keys should be bech32-encoded with prefix \
+        \'X_vkh', 'X_vk', 'X_xvk' where X is 'addr_shared', 'stake_shared' or 'policy' and\
         \timelocks must use non-negative numbers as slots."
     NotRecommended EmptyList ->
         "The list inside a script is empty or only contains timelocks \
@@ -562,7 +571,7 @@ prettyErrValidateScriptTemplate = \case
     DuplicateXPubs ->
         "The cosigners in a script template must stand behind an unique extended public key."
     MissingCosignerXPub ->
-        "Each cosigner in a script template must have extended public key."
+        "Each cosigner in a script template must have an extended public key."
     NoCosignerInScript ->
         "The script of a template must have at least one cosigner defined."
     NoCosignerXPub ->
@@ -650,7 +659,7 @@ instance FromJSON (Script KeyHash) where
                     (Nothing, Just{}, Nothing)  -> parseAllOf v
                     (Nothing, Nothing, Just{})  -> parseAtLeast v
                     (Nothing, Nothing, Nothing) -> fail
-                        "Found object with no known key 'any', 'all' or 'some'"
+                        "Found object with unknown key. Expecting 'any', 'all' or 'some'"
                     (      _,       _,      _)  -> fail
                         "Found multiple keys 'any', 'all' and/or 'some' at the same level"
             String{} ->
@@ -722,7 +731,7 @@ instance FromJSON Cosigner where
                         fail "Cosigner number should be between '0' and '255'"
                 pure $ Cosigner num
             _ -> fail "Cosigner should be enumerated with number"
-        _ -> fail "Cosigner should be of form: cosigner#num"
+        _ -> fail "Cosigner should be of the form: cosigner#num"
 
 encodeXPub :: XPub -> Value
 encodeXPub = String . T.decodeUtf8 . encode EBase16 . xpubToBytes
@@ -762,7 +771,7 @@ instance FromJSON (Script Cosigner) where
                     (Nothing, Nothing, Just{}, Nothing)  -> parseAtLeast v
                     (Nothing, Nothing, Nothing, Just{})  -> parserCosigner v
                     (Nothing, Nothing, Nothing, Nothing) -> fail
-                        "Found object with no known key 'any', 'all', 'some' or 'cosigner'"
+                        "Found object with unknown key. Expecting 'any', 'all', 'some' or 'cosigner'"
                     (      _,       _,      _,       _)  -> fail
                         "Found multiple keys 'any', 'all', 'cosigner' and/or 'some' at the same level"
             _ ->
diff --git a/core/lib/Cardano/Address/Style/Shelley.hs b/core/lib/Cardano/Address/Style/Shelley.hs
index 520d260a2..02457fdfb 100644
--- a/core/lib/Cardano/Address/Style/Shelley.hs
+++ b/core/lib/Cardano/Address/Style/Shelley.hs
@@ -41,6 +41,7 @@ module Cardano.Address.Style.Shelley
     , deriveAddressPrivateKey
     , deriveDelegationPrivateKey
     , deriveAddressPublicKey
+    , derivePolicyPrivateKey
 
       -- * Addresses
       -- $addresses
@@ -310,6 +311,18 @@ deriveAccountPrivateKey
 deriveAccountPrivateKey =
     Internal.deriveAccountPrivateKey
 
+-- Re-export from 'Cardano.Address.Derivation' to have it documented specialized in Haddock.
+--
+-- | Derives a policy private key from the given root private key.
+--
+-- @since 3.9.0
+derivePolicyPrivateKey
+    :: Shelley 'RootK XPrv
+    -> Index 'Hardened 'PolicyK
+    -> Shelley 'PolicyK XPrv
+derivePolicyPrivateKey (Shelley rootXPrv) policyIx =
+    Shelley $ deriveAccountPrivateKeyShelley rootXPrv policyIx policyPurposeIndex
+
 -- Re-export from 'Cardano.Address.Derivation' to have it documented specialized in Haddock.
 --
 -- | Derives an address private key from the given account private key.
@@ -979,6 +992,17 @@ unsafeFromRight =
 purposeIndex :: Word32
 purposeIndex = 0x8000073c
 
+-- Policy purpose is a constant set to 1855' (or 0x8000073c) following the CIP-1855
+-- https://github.com/cardano-foundation/CIPs/tree/master/CIP-1855
+--
+-- It indicates that the subtree of this node is used according to this
+-- specification.
+--
+-- Hardened derivation is used at this level.
+policyPurposeIndex :: Word32
+policyPurposeIndex = 0x8000073f
+
+
 -- One master node (seed) can be used for unlimited number of independent
 -- cryptocoins such as Bitcoin, Litecoin or Namecoin. However, sharing the
 -- same space for various cryptocoins has some disadvantages.
diff --git a/core/lib/Cardano/Codec/Bech32/Prefixes.hs b/core/lib/Cardano/Codec/Bech32/Prefixes.hs
index f189901f7..a11924f93 100644
--- a/core/lib/Cardano/Codec/Bech32/Prefixes.hs
+++ b/core/lib/Cardano/Codec/Bech32/Prefixes.hs
@@ -57,6 +57,11 @@ module Cardano.Codec.Bech32.Prefixes
     , stake_shared_xvk
     , stake_shared_xsk
 
+      -- * Keys for 1855H
+    , policy_vk
+    , policy_xvk
+    , policy_vkh
+    , policy_xsk
     ) where
 
 import Codec.Binary.Bech32
@@ -194,3 +199,16 @@ addr_shared_vkh = [humanReadablePart|addr_shared_vkh|]
 
 stake_shared_vkh :: HumanReadablePart
 stake_shared_vkh = [humanReadablePart|stake_shared_vkh|]
+
+-- Policy
+policy_vk :: HumanReadablePart
+policy_vk = [humanReadablePart|policy_vk|]
+
+policy_xvk :: HumanReadablePart
+policy_xvk = [humanReadablePart|policy_xvk|]
+
+policy_vkh :: HumanReadablePart
+policy_vkh = [humanReadablePart|policy_vkh|]
+
+policy_xsk :: HumanReadablePart
+policy_xsk = [humanReadablePart|policy_xsk|]
diff --git a/core/test/Cardano/Address/ScriptSpec.hs b/core/test/Cardano/Address/ScriptSpec.hs
index f432579a1..d239aa84b 100644
--- a/core/test/Cardano/Address/ScriptSpec.hs
+++ b/core/test/Cardano/Address/ScriptSpec.hs
@@ -674,7 +674,7 @@ spec = do
                 `shouldBe` Left err
 
         it "Unknown keys" $ do
-            let err = "Error in $: Found object with no known key 'any', 'all' or 'some'"
+            let err = "Error in $: Found object with unknown key. Expecting 'any', 'all' or 'some'"
             Json.eitherDecode @(Script KeyHash) "{ \"patate\": {} }"
                 `shouldBe` Left err