diff --git a/crypto/src/jni-crypto/Cargo.toml b/crypto/src/jni-crypto/Cargo.toml
index 5cbf3b59..220015b4 100644
--- a/crypto/src/jni-crypto/Cargo.toml
+++ b/crypto/src/jni-crypto/Cargo.toml
@@ -12,6 +12,12 @@ curve25519-dalek = { version = "2.1.0", default-features = false }
 schnorrkel = { version = "0.9.1", features = ["preaudit_deprecated", "u64_backend"] }
 hex = "0.4.3"
 
+# Pinned transitive dependencies
+proc-macro2 = { version = "=1.0.81" }
+unicode-ident = { version = "=1.0.12" }
+quote = { version = "=1.0.36" }
+log = { version = "=0.4.21" }
+
 [dev-dependencies]
 hex-literal = "0.2.0"
-rand = { version = "0.7.3", features = ["wasm-bindgen"] }
\ No newline at end of file
+rand = { version = "0.7.3", features = ["wasm-bindgen"] }
diff --git a/rpc/rpc-api/src/main/java/com/strategyobject/substrateclient/rpc/api/AccountIdDecoder.java b/rpc/rpc-api/src/main/java/com/strategyobject/substrateclient/rpc/api/AccountIdDecoder.java
new file mode 100644
index 00000000..3a6dfd36
--- /dev/null
+++ b/rpc/rpc-api/src/main/java/com/strategyobject/substrateclient/rpc/api/AccountIdDecoder.java
@@ -0,0 +1,22 @@
+package com.strategyobject.substrateclient.rpc.api;
+
+import com.strategyobject.substrateclient.crypto.ss58.SS58Codec;
+import com.strategyobject.substrateclient.rpc.DecoderPair;
+import com.strategyobject.substrateclient.rpc.RpcDecoder;
+import com.strategyobject.substrateclient.rpc.annotation.AutoRegister;
+import com.strategyobject.substrateclient.transport.RpcObject;
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor
+@AutoRegister(types = AccountId.class)
+public class AccountIdDecoder implements RpcDecoder<AccountId> {
+
+    @Override
+    public AccountId decode(RpcObject value, DecoderPair<?>... decoders) {
+        if (value.isNull()) { return null; }
+        if (decoders != null && decoders.length > 0) throw new IllegalArgumentException();
+
+        return AccountId.fromBytes(SS58Codec.decode(value.asString()).getAddress());
+    }
+
+}