diff --git a/src/main/jwt_full/private/crypto/ecdsa.nim b/src/main/jwt_full/private/crypto/ecdsa.nim
index 13dc9cb..6f296e2 100644
--- a/src/main/jwt_full/private/crypto/ecdsa.nim
+++ b/src/main/jwt_full/private/crypto/ecdsa.nim
@@ -96,7 +96,7 @@ proc getEcHashCfg(alg: JwtAlgorithm): HashCfg =
     else: raise newException(ValueError,
       "Unsupported ECDSA signature algorithm '" & $alg & "'")
 
-  result = HASHES[hashAlg]
+  result = hashConfig(hashAlg)
 
 proc bearEcSign(
     message: string,
diff --git a/src/main/jwt_full/private/crypto/hash.nim b/src/main/jwt_full/private/crypto/hash.nim
index fc0062e..4ada3ea 100644
--- a/src/main/jwt_full/private/crypto/hash.nim
+++ b/src/main/jwt_full/private/crypto/hash.nim
@@ -33,11 +33,37 @@ let HASHES* = newTable[HashAlgorithm, HashCfg]([
     size: sha512Size)),
 ])
 
+proc hashConfig*(alg: HashAlgorithm): HashCfg =
+  case alg:
+    of SHA1: return HashCfg(
+      alg: SHA1,
+      vtable: addr sha1Vtable,
+      oid: HASH_OID_SHA1,
+      size: sha1Size)
+
+    of SHA256: return HashCfg(
+      alg: SHA256,
+      vtable: addr sha256Vtable,
+      oid: HASH_OID_SHA256,
+      size: sha256Size)
+
+    of SHA384: return HashCfg(
+      alg: SHA384,
+      vtable: addr sha384Vtable,
+      oid: HASH_OID_SHA384,
+      size: sha384Size)
+
+    of SHA512: return HashCfg(
+      alg: SHA512,
+      vtable: addr sha512Vtable,
+      oid: HASH_OID_SHA512,
+      size: sha512Size)
+
 proc hash*(data: string, alg: HashAlgorithm): string =
 
   var ctx: HashCompatContext
   var pCtx = cast[ptr ptr HashClass](addr ctx)
-  let hashCfg = HASHES[alg]
+  let hashCfg = hashConfig(alg)
   result = newString(hashCfg.size)
   hashCfg.vtable.init(pCtx)
   hashCfg.vtable.update(pCtx, unsafeAddr data[0], data.len)
diff --git a/src/main/jwt_full/private/crypto/rsa.nim b/src/main/jwt_full/private/crypto/rsa.nim
index d49053f..865cf47 100644
--- a/src/main/jwt_full/private/crypto/rsa.nim
+++ b/src/main/jwt_full/private/crypto/rsa.nim
@@ -133,7 +133,7 @@ proc getRsaHashCfg(alg: JwtAlgorithm): HashCfg =
     else: raise newException(ValueError,
       "Unsupported RSA signature algorithm '" & $alg & "'")
 
-  result = HASHES[hashAlg]
+  result = hashConfig(hashAlg)
 
 proc bearRsaSign(
     message: string,