diff --git a/abc/keys.nim b/abc/keys.nim
index a4f3f09..0db9404 100644
--- a/abc/keys.nim
+++ b/abc/keys.nim
@@ -6,9 +6,9 @@ type
   PublicKey* = distinct bls.PublicKey
   Signature* = distinct bls.Signature
 
-proc `==`*(a, b: PrivateKey): bool {.borrow.}
-proc `==`*(a, b: PublicKey): bool {.borrow.}
-proc `==`*(a, b: Signature): bool {.borrow.}
+func `==`*(a, b: PrivateKey): bool {.borrow.}
+func `==`*(a, b: PublicKey): bool {.borrow.}
+func `==`*(a, b: Signature): bool {.borrow.}
 
 proc random*(_: type PrivateKey): PrivateKey =
   var seed = newSeq[byte](64)
@@ -16,16 +16,16 @@ proc random*(_: type PrivateKey): PrivateKey =
   doAssert deriveMasterSecretKey(bls.SecretKey(result), seed)
   burnArray(seed)
 
-proc erase*(key: var PrivateKey) =
+func erase*(key: var PrivateKey) =
   burnMem(key)
 
-proc toPublicKey*(private: PrivateKey): PublicKey =
+func toPublicKey*(private: PrivateKey): PublicKey =
   doAssert publicFromSecret(bls.PublicKey(result), bls.SecretKey(private))
 
-proc sign*(key: PrivateKey, message: openArray[byte]): Signature =
+func sign*(key: PrivateKey, message: openArray[byte]): Signature =
   Signature(bls.SecretKey(key).sign(message))
 
-proc verify*(key: PublicKey,
+func verify*(key: PublicKey,
              message: openArray[byte],
              signature: Signature): bool =
   ## TODO: not safe w.r.t. rogue public-key attack. Needs implementation of