diff --git a/packages/sdk/src/address.spec.ts b/packages/sdk/src/address.spec.ts
new file mode 100644
index 00000000..5f9b2cc6
--- /dev/null
+++ b/packages/sdk/src/address.spec.ts
@@ -0,0 +1,56 @@
+import { Encoding } from "@iov/encoding";
+
+import { decodeBech32Pubkey, isValidAddress, pubkeyToAddress } from "./address";
+import { PubKeyEd25519, PubKeySecp256k1 } from "./types";
+
+const { toBase64, fromHex } = Encoding;
+
+describe("address", () => {
+  describe("decodeBech32Pubkey", () => {
+    it("works", () => {
+      expect(
+        decodeBech32Pubkey("cosmospub1addwnpepqd8sgxq7aw348ydctp3n5ajufgxp395hksxjzc6565yfp56scupfqhlgyg5"),
+      ).toEqual({
+        type: "tendermint/PubKeySecp256k1",
+        value: "A08EGB7ro1ORuFhjOnZcSgwYlpe0DSFjVNUIkNNQxwKQ",
+      });
+    });
+  });
+
+  describe("isValidAddress", () => {
+    it("accepts valid addresses", () => {
+      expect(isValidAddress("cosmos1pkptre7fdkl6gfrzlesjjvhxhlc3r4gmmk8rs6")).toEqual(true);
+      expect(isValidAddress("cosmosvalcons10q82zkzzmaku5lazhsvxv7hsg4ntpuhdwadmss")).toEqual(true);
+      expect(isValidAddress("cosmosvaloper17mggn4znyeyg25wd7498qxl7r2jhgue8u4qjcq")).toEqual(true);
+    });
+
+    it("rejects invalid addresses", () => {
+      // Bad size
+      expect(isValidAddress("cosmos10q82zkzzmaku5lazhsvxv7hsg4ntpuhh8289f")).toEqual(false);
+      // Bad checksum
+      expect(isValidAddress("cosmos1pkptre7fdkl6gfrzlesjjvhxhlc3r4gmmk8rs7")).toEqual(false);
+      // Bad prefix
+      expect(isValidAddress("cosmot10q82zkzzmaku5lazhsvxv7hsg4ntpuhd8j5266")).toEqual(false);
+    });
+  });
+
+  describe("pubkeyToAddress", () => {
+    it("works for Secp256k1 compressed", () => {
+      const prefix = "cosmos";
+      const pubkey: PubKeySecp256k1 = {
+        type: "tendermint/PubKeySecp256k1",
+        value: "AtQaCqFnshaZQp6rIkvAPyzThvCvXSDO+9AzbxVErqJP",
+      };
+      expect(pubkeyToAddress(pubkey, prefix)).toEqual("cosmos1h806c7khnvmjlywdrkdgk2vrayy2mmvf9rxk2r");
+    });
+
+    it("works for Ed25519", () => {
+      const prefix = "cosmos";
+      const pubkey: PubKeyEd25519 = {
+        type: "tendermint/PubKeyEd25519",
+        value: toBase64(fromHex("12ee6f581fe55673a1e9e1382a0829e32075a0aa4763c968bc526e1852e78c95")),
+      };
+      expect(pubkeyToAddress(pubkey, prefix)).toEqual("cosmos1pfq05em6sfkls66ut4m2257p7qwlk448h8mysz");
+    });
+  });
+});
diff --git a/packages/sdk/src/address.ts b/packages/sdk/src/address.ts
new file mode 100644
index 00000000..13f13b7f
--- /dev/null
+++ b/packages/sdk/src/address.ts
@@ -0,0 +1,109 @@
+import { Ripemd160, Sha256 } from "@iov/crypto";
+import { Bech32, Encoding } from "@iov/encoding";
+import equal from "fast-deep-equal";
+
+import { Bech32PubKey, PubKey } from "./types";
+
+const { fromBase64, toBase64 } = Encoding;
+
+// TODO: make this much more configurable
+export type CosmosAddressBech32Prefix = "cosmos" | "cosmosvalcons" | "cosmosvaloper";
+export type CosmosPubkeyBech32Prefix = "cosmospub" | "cosmosvalconspub" | "cosmosvaloperpub";
+export type CosmosBech32Prefix = CosmosAddressBech32Prefix | CosmosPubkeyBech32Prefix;
+
+function isCosmosAddressBech32Prefix(prefix: string): prefix is CosmosAddressBech32Prefix {
+  return ["cosmos", "cosmosvalcons", "cosmosvaloper"].includes(prefix);
+}
+
+function isCosmosPubkeyBech32Prefix(prefix: string): prefix is CosmosPubkeyBech32Prefix {
+  return ["cosmospub", "cosmosvalconspub", "cosmosvaloperpub"].includes(prefix);
+}
+
+// As discussed in https://github.com/binance-chain/javascript-sdk/issues/163
+// Prefixes listed here: https://github.com/tendermint/tendermint/blob/d419fffe18531317c28c29a292ad7d253f6cafdf/docs/spec/blockchain/encoding.md#public-key-cryptography
+// Last bytes is varint-encoded length prefix
+const pubkeyAminoPrefixSecp256k1 = Encoding.fromHex("eb5ae98721");
+const pubkeyAminoPrefixEd25519 = Encoding.fromHex("1624de6420");
+const pubkeyAminoPrefixSr25519 = Encoding.fromHex("0dfb1005");
+const pubkeyAminoPrefixLength = pubkeyAminoPrefixSecp256k1.length;
+
+export function decodeBech32Pubkey(bech: Bech32PubKey): PubKey {
+  const { prefix, data } = Bech32.decode(bech);
+  if (!isCosmosPubkeyBech32Prefix(prefix)) {
+    throw new Error(`Invalid bech32 prefix. Must be one of cosmos, cosmosvalcons, or cosmosvaloper.`);
+  }
+
+  const aminoPrefix = data.slice(0, pubkeyAminoPrefixLength);
+  const rest = data.slice(pubkeyAminoPrefixLength);
+  if (equal(aminoPrefix, pubkeyAminoPrefixSecp256k1)) {
+    if (rest.length !== 33) {
+      throw new Error("Invalid rest data length. Expected 33 bytes (compressed secp256k1 pubkey).");
+    }
+    return {
+      type: "tendermint/PubKeySecp256k1",
+      value: toBase64(rest),
+    };
+  } else if (equal(aminoPrefix, pubkeyAminoPrefixEd25519)) {
+    if (rest.length !== 32) {
+      throw new Error("Invalid rest data length. Expected 32 bytes (Ed25519 pubkey).");
+    }
+    return {
+      type: "tendermint/PubKeyEd25519",
+      value: toBase64(rest),
+    };
+  } else if (equal(aminoPrefix, pubkeyAminoPrefixSr25519)) {
+    if (rest.length !== 32) {
+      throw new Error("Invalid rest data length. Expected 32 bytes (Sr25519 pubkey).");
+    }
+    return {
+      type: "tendermint/PubKeySr25519",
+      value: toBase64(rest),
+    };
+  } else {
+    throw new Error("Unsupported Pubkey type. Amino prefix: " + Encoding.toHex(aminoPrefix));
+  }
+}
+
+export function isValidAddress(address: string): boolean {
+  try {
+    const { prefix, data } = Bech32.decode(address);
+    if (!isCosmosAddressBech32Prefix(prefix)) {
+      return false;
+    }
+    return data.length === 20;
+  } catch {
+    return false;
+  }
+}
+
+// See https://github.com/tendermint/tendermint/blob/f2ada0a604b4c0763bda2f64fac53d506d3beca7/docs/spec/blockchain/encoding.md#public-key-cryptography
+// This assumes we already have a cosmos-compressed pubkey
+export function pubkeyToAddress(pubkey: PubKey, prefix: string): string {
+  const pubkeyBytes = fromBase64(pubkey.value);
+  switch (pubkey.type) {
+    case "tendermint/PubKeySecp256k1": {
+      if (pubkeyBytes.length !== 33) {
+        throw new Error(`Invalid Secp256k1 pubkey length (compressed): ${pubkeyBytes.length}`);
+      }
+      const hash1 = new Sha256(pubkeyBytes).digest();
+      const hash2 = new Ripemd160(hash1).digest();
+      return Bech32.encode(prefix, hash2);
+    }
+    case "tendermint/PubKeyEd25519": {
+      if (pubkeyBytes.length !== 32) {
+        throw new Error(`Invalid Ed25519 pubkey length: ${pubkeyBytes.length}`);
+      }
+      const hash = new Sha256(pubkeyBytes).digest();
+      return Bech32.encode(prefix, hash.slice(0, 20));
+    }
+    case "tendermint/PubKeySr25519": {
+      if (pubkeyBytes.length !== 32) {
+        throw new Error(`Invalid Sr25519 pubkey length: ${pubkeyBytes.length}`);
+      }
+      const hash = new Sha256(pubkeyBytes).digest();
+      return Bech32.encode(prefix, hash.slice(0, 20));
+    }
+    default:
+      throw new Error("Unrecognized public key algorithm");
+  }
+}
diff --git a/packages/sdk/src/restclient.spec.ts b/packages/sdk/src/restclient.spec.ts
index 41e9db67..a490139a 100644
--- a/packages/sdk/src/restclient.spec.ts
+++ b/packages/sdk/src/restclient.spec.ts
@@ -78,7 +78,8 @@ describe("RestClient", () => {
   describe("encodeTx", () => {
     it("works for cosmoshub example", async () => {
       pendingWithoutCosmos();
-      const tx: StdTx = data.tx.value;
+      // need to convince the compiler we have a valid string for pubkey type
+      const tx: StdTx = data.tx.value as StdTx;
       const client = new RestClient(httpUrl);
       expect(await client.encodeTx(tx)).toEqual(fromBase64(data.tx_data));
     });
diff --git a/packages/sdk/src/types.ts b/packages/sdk/src/types.ts
index 1404e90d..2aa16d64 100644
--- a/packages/sdk/src/types.ts
+++ b/packages/sdk/src/types.ts
@@ -100,19 +100,33 @@ export interface StdSignature {
   readonly signature: string;
 }
 
-export interface PubKey {
-  readonly type: string;
+// value field is base64-encoded in all cases
+export type PubKey = PubKeyEd25519 | PubKeySecp256k1 | PubKeySr25519;
+
+export interface PubKeySecp256k1 {
+  readonly type: "tendermint/PubKeySecp256k1";
+  // Note: this contains a Secp256k1 COMPRESSED pubkey - to encode from bcp/keycontrol land, you must compress it first
   readonly value: string;
 }
 
-// AccountPubKey is bech32-encoded amino-binary encoded PubKey interface. oof.
-export type AccountPubKey = string;
+export interface PubKeyEd25519 {
+  readonly type: "tendermint/PubKeyEd25519";
+  readonly value: string;
+}
+
+export interface PubKeySr25519 {
+  readonly type: "tendermint/PubKeySr25519";
+  readonly value: string;
+}
+
+// Bech32PubKey is bech32-encoded amino-binary encoded PubKey interface. oof.
+export type Bech32PubKey = string;
 
 export interface BaseAccount {
   /** Bech32 account address */
   readonly address: string;
   readonly coins: ReadonlyArray<Coin>;
-  readonly public_key: AccountPubKey;
+  readonly public_key: Bech32PubKey;
   readonly account_number: number;
   readonly sequence: number;
 }
diff --git a/packages/sdk/types/address.d.ts b/packages/sdk/types/address.d.ts
new file mode 100644
index 00000000..fbb34ec2
--- /dev/null
+++ b/packages/sdk/types/address.d.ts
@@ -0,0 +1,7 @@
+import { Bech32PubKey, PubKey } from "./types";
+export declare type CosmosAddressBech32Prefix = "cosmos" | "cosmosvalcons" | "cosmosvaloper";
+export declare type CosmosPubkeyBech32Prefix = "cosmospub" | "cosmosvalconspub" | "cosmosvaloperpub";
+export declare type CosmosBech32Prefix = CosmosAddressBech32Prefix | CosmosPubkeyBech32Prefix;
+export declare function decodeBech32Pubkey(bech: Bech32PubKey): PubKey;
+export declare function isValidAddress(address: string): boolean;
+export declare function pubkeyToAddress(pubkey: PubKey, prefix: string): string;
diff --git a/packages/sdk/types/types.d.ts b/packages/sdk/types/types.d.ts
index 962c80c0..4723c474 100644
--- a/packages/sdk/types/types.d.ts
+++ b/packages/sdk/types/types.d.ts
@@ -70,16 +70,25 @@ export interface StdSignature {
   readonly pub_key: PubKey;
   readonly signature: string;
 }
-export interface PubKey {
-  readonly type: string;
+export declare type PubKey = PubKeyEd25519 | PubKeySecp256k1 | PubKeySr25519;
+export interface PubKeySecp256k1 {
+  readonly type: "tendermint/PubKeySecp256k1";
   readonly value: string;
 }
-export declare type AccountPubKey = string;
+export interface PubKeyEd25519 {
+  readonly type: "tendermint/PubKeyEd25519";
+  readonly value: string;
+}
+export interface PubKeySr25519 {
+  readonly type: "tendermint/PubKeySr25519";
+  readonly value: string;
+}
+export declare type Bech32PubKey = string;
 export interface BaseAccount {
   /** Bech32 account address */
   readonly address: string;
   readonly coins: ReadonlyArray<Coin>;
-  readonly public_key: AccountPubKey;
+  readonly public_key: Bech32PubKey;
   readonly account_number: number;
   readonly sequence: number;
 }