diff --git a/.prettierrc.json b/.prettierrc.json
new file mode 100644
index 0000000..bf357fb
--- /dev/null
+++ b/.prettierrc.json
@@ -0,0 +1,3 @@
+{
+  "trailingComma": "all"
+}
diff --git a/.vscode/settings.json b/.vscode/settings.json
index 521eda4..a08982f 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -1,7 +1,5 @@
 {
-    "deno.enableFormatter": true,
-    "editor.formatOnSave": true,
-    "editor.tabSize": 2,
-    "deno.enable": true,
-    "files.eol": "\n"
-}
\ No newline at end of file
+  "editor.tabSize": 2,
+  "deno.enable": true,
+  "files.eol": "\n",
+}
diff --git a/src/rsa/basic_encoding_rule.ts b/src/rsa/basic_encoding_rule.ts
index a2d9833..c2fda24 100644
--- a/src/rsa/basic_encoding_rule.ts
+++ b/src/rsa/basic_encoding_rule.ts
@@ -55,10 +55,7 @@ function ber_integer(bytes: Uint8Array, from: number, length: number): bigint {
 }
 
 function ber_oid(bytes: Uint8Array, from: number, length: number): string {
-  const id = [
-    (bytes[from] / 40) | 0,
-    (bytes[from] % 40),
-  ];
+  const id = [(bytes[from] / 40) | 0, bytes[from] % 40];
   let value = 0;
 
   for (const b of bytes.slice(from + 1, from + length)) {
@@ -125,7 +122,7 @@ function ber_next(
   }
 
   return {
-    totalLength: (ptr - from) + size,
+    totalLength: ptr - from + size,
     type,
     length: size,
     value,
diff --git a/src/rsa/import_key.ts b/src/rsa/import_key.ts
index a8078c2..10e60ab 100644
--- a/src/rsa/import_key.ts
+++ b/src/rsa/import_key.ts
@@ -94,6 +94,33 @@ function rsa_import_pem_private(key: string): RSAKeyParams {
   };
 }
 
+/**
+ * Import private key from Privacy-Enhanced Mail (PEM) format
+ * https://tools.ietf.org/html/rfc5208
+ *
+ * @param key PEM encoded key format
+ */
+function rsa_import_pem_private_pkcs8(key: string): RSAKeyParams {
+  const trimmedKey = key.substr(27, key.length - 57);
+  const parseWrappedKey = ber_simple(
+    ber_decode(base64_to_binary(trimmedKey)),
+  ) as [number, unknown, Uint8Array];
+
+  const parseKey = ber_simple(ber_decode(parseWrappedKey[2])) as bigint[];
+
+  return {
+    n: parseKey[1],
+    d: parseKey[3],
+    e: parseKey[2],
+    p: parseKey[4],
+    q: parseKey[5],
+    dp: parseKey[6],
+    dq: parseKey[7],
+    qi: parseKey[8],
+    length: get_key_size(parseKey[1]),
+  };
+}
+
 /**
  * Import public key from Privacy-Enhanced Mail (PEM) format
  * https://tools.ietf.org/html/rfc5208
@@ -124,6 +151,7 @@ function rsa_import_pem(key: string): RSAKeyParams {
 
   const maps: [string, (key: string) => RSAKeyParams][] = [
     ["-----BEGIN RSA PRIVATE KEY-----", rsa_import_pem_private],
+    ["-----BEGIN PRIVATE KEY-----", rsa_import_pem_private_pkcs8],
     ["-----BEGIN PUBLIC KEY-----", rsa_import_pem_public],
     ["-----BEGIN CERTIFICATE-----", rsa_import_pem_cert],
   ];
diff --git a/tests/rsa/rsa.import_key.test.ts b/tests/rsa/rsa.import_key.test.ts
index 7b11fbd..6c6a6e8 100644
--- a/tests/rsa/rsa.import_key.test.ts
+++ b/tests/rsa/rsa.import_key.test.ts
@@ -3,13 +3,12 @@ import { assertEquals } from "https://deno.land/std@0.63.0/testing/asserts.ts";
 
 Deno.test("RSA - Import JWK Public Key", () => {
   const jwk = {
-    "e": "AQAB",
-    "alg": "RS256",
-    "use": "sig",
-    "n":
-      "7NfiTQcshWgrEdKbHC2e1s92kK-YX7jS3JLFIBpT8f_j_b5y3dQdtFFS4vBoVNQkwep_34x_ihYlhA3QkwaTL2XMSiedjLnubFZBUjs7G0dgGIR3F8A06Bf5KT4g2x1dKVb0Lwwqg22XIfqaS88HdU5pDwcVmq4pVMaJQgUK-xFEC_sHdfqTV8Z0uBCr9Nik_7xz68FINDYyLhehnvwph9ui-8_WeDgU_h5xrG8H7oY28y2NCtBwXxIadB-K8pHxK2srM8wTCIivdyZS80P0jZMqyxPkt4fO33-GQWvelVmR0bS4Arb3Y4bXnoAMCEao3DTm0bgeNVz39274ippJSQ",
-    "kty": "RSA",
-    "kid": "0a7dc12664590c957ffaebf7b6718297b864ba91",
+    e: "AQAB",
+    alg: "RS256",
+    use: "sig",
+    n: "7NfiTQcshWgrEdKbHC2e1s92kK-YX7jS3JLFIBpT8f_j_b5y3dQdtFFS4vBoVNQkwep_34x_ihYlhA3QkwaTL2XMSiedjLnubFZBUjs7G0dgGIR3F8A06Bf5KT4g2x1dKVb0Lwwqg22XIfqaS88HdU5pDwcVmq4pVMaJQgUK-xFEC_sHdfqTV8Z0uBCr9Nik_7xz68FINDYyLhehnvwph9ui-8_WeDgU_h5xrG8H7oY28y2NCtBwXxIadB-K8pHxK2srM8wTCIivdyZS80P0jZMqyxPkt4fO33-GQWvelVmR0bS4Arb3Y4bXnoAMCEao3DTm0bgeNVz39274ippJSQ",
+    kty: "RSA",
+    kid: "0a7dc12664590c957ffaebf7b6718297b864ba91",
   };
 
   const key = RSA.importKey(jwk);
@@ -49,3 +48,46 @@ Deno.test("RSA - Import Certificate PEM", () => {
   );
   assertEquals(key.length, 256);
 });
+
+Deno.test("RSA - Import Private Key (PKCS8)", () => {
+  const raw = `-----BEGIN PRIVATE KEY-----
+  MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQCVZ6og4XGxLAHH
+  ZwHm27AtUMP6+8wFqllvup0Tr0V21YvxzPxWjav2+mLOIM8upa7pzvcpc5EiCH58
+  denmLJsygqo0r2B8WhzHY+rCIWJfV2YSZxjzpvSAHfzLJrDphXgqgnCNxEjRsuyC
+  YAiGLIMK0huY90A5MMMArgUzkx8kMd/fq/Gd9Xt5iI+F7NlylJ+arnJc306pgGHK
+  3NN2GBX1vnSuCB280SUXkZfTBeykyDZ6YrAq0XpnCNV9JyHqLQ4EmjEhc2yUo3aN
+  RyXNMBddZx3HCLFcxwZCVAp0tQkAd7ErsUD5P5DR8RIJ3frklSUUZB6EkDw8G7KL
+  WKVcNQ2FAgMBAAECggEABVqkmOQ4s2PzlgkDDdofxJFL+KhXMyPGlo+uNd32hA/v
+  4YTaTSLAv8t7c3jEW/RW4ezyDrj5bD9i2FnPEu8pyk6u7qTon67eBaeMapO7h1Wl
+  5DEazo5+3WwrBT+4ICI8QG+8vK6E+ojU23DkFU+D4a/OX+C1GzzmsWqgZ+z/inKL
+  aMwS6rsWROUlgA1x5zNSoqC3SJFllVXXew5UyANTsBjvQ5J2Mmb9g8CEaAOn+xMk
+  xNlwTlDot+09nFJ9vvAWirUkZdsYNnlY+zrDQoPT7Am5jtKTHmMI1KfWNfmznyji
+  RltdnWfd8Bg0H7VtwrhWMWGs8QkATUAE+fC3qS144QKBgQDNFLk8eMwK6koMoNmY
+  vsRAf1Y6Xdd+LUN+TJqkZiUEySaKy8NLi71IBbzK7zKqbYXDPUFCbNJFhOlluKOw
+  bsKPkwBjR0JfoXVzbUdE+2tM2YccswaJe7iinZxr0wHGXIvJL0HNVIzmNggS7+Zm
+  rEsdCyFXnTT/83o1wVW3E/lspQKBgQC6gBVyYCP7AxYHTSRDCgcpsTO7HyzuY92t
+  aYOhRJFC7HNbzJbVdVsfnbtQH/Epe8ySk91GyFZ1dSJrxetcLhHsS2TMrkYUmY4x
+  bJnqzJTh7cgWBP9DuWYvSJxPooSpFwbh2L12vQ2ADpwwoAZMLkAagaGlY9MZz821
+  XY+KkOLnYQKBgQCQ49lTTgzqkUirz2Cst+qznsNvDSnYbWZH7xs6lygET5E5cmiS
+  ETIzlkoiHgjvu91LaRWYNoYAs7yqL18Godo30aXufkP4iHwQht5ZcEAI1Y7NyfYO
+  YCi8SxpeW3/fgzcHdqnIxbmeVAI0TuW7GHMhG+H8oob1ZjGrlOJYLHaGOQKBgDLO
+  vgkAxAyYFKI8k8pnqvfivJMXtSfksPmTKzb99QzkWbEClXzlkcOVNvhnG04P2fV8
+  ruWfol4xYQU3UB02t89F4toYCCOIicJRMcVToqPCIaZOCjSrB3mOMHdJcRaXnVpd
+  r4/vhQQD9u0QS2bpmrEd66mg/lujzwi/ymEXg5lBAoGAacrPblD+G/DAmTUt3tZw
+  GLdIvw4BeDyCvzxkJx1Z04rMZH71EEyBDPMBByZNPtjpTuzgAZE71MiD3BVLxj/H
+  dqEjUVQSjuOUyiJKe5GiGF25Xhe3/1VawurCdHfrv6Xmze+lRDHZuEOcV1FrM+zn
+  KQXlkpPbL3lU2CpgGFFKlFU=
+  -----END PRIVATE KEY-----`;
+
+  const key = RSA.importKey(raw);
+  assertEquals(key.e, 65537n);
+  assertEquals(
+    key.n,
+    18860626341786571281488823024986320858450594409825894653370543036132043241142573896042059032222842653925236802058387508300831766517210547599910735316414515960981281788934868325895562621846910598716519620622800765932541992515497122274302135166053720433521886017494719475895327062855822141735315456613329660043977602681873027347568355824008701177948209784908095092287571982104446342906805480285143028837509076748632094733769028381835899214426100089454654381383340292544225149266603150745375542089871264998183586873913491071542891188124185517417658034185267204900711933432911892469528812455677450346478816563776340692357n,
+  );
+  assertEquals(
+    key.d,
+    675889233296421535959584534071325460876697008626327098961835826056666939623318583538247287416696388446697983317835135300723690022117970081796395234018582764098060974026823771341271141202058228435371968592820841644512299636165137501280011132877728106486853881053264668544941537620562475421678333757690909726581512579603702598150422421865490996288244127528474781858718770957987603681469839575489191876915053252047160475432784849252000744700939988583801783684487872676506769116621572018367654125765915215495461243190782913460732307866572233187464540482209385816659449697777403383908159076257721991916366849321145825505n,
+  );
+  assertEquals(key.length, 256);
+});