feat: add sncrypto client side packages

packages/sncrypto-common/src/AES-GCM/Aes256GcmEncrypted.ts

@@ -0,0 +1,17 @@
+import { Base64String } from '../Types/Base64String'
+import { HexString } from '../Types/HexString'
+
+/**
+ * @param iv initialization vector as a hex string
+ * @param tag authentication tag as a hex string
+ * @param ciphertext as a base64 string
+ * @param encoding that will be applied after decrypting
+ * @param aad additional authenticated data as a hex string
+ */
+export type Aes256GcmEncrypted<EncodingType> = {
+  iv: HexString
+  tag: HexString
+  ciphertext: Base64String
+  encoding: EncodingType
+  aad: HexString
+}

packages/sncrypto-common/src/AES-GCM/Aes256GcmInput.ts

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+import { HexString } from '../Types/HexString'
+import { Unencrypted } from '../Types/Unencrypted'
+
+/**
+ * @param unencrypted -- UTF-8 string or a `string` with `encoding`
+ * @param iv initialization vector as a hex string
+ * @param key encryption key as a hex string
+ * @param aad additional authenticated data as a hex string
+ */
+export type Aes256GcmInput<EncodingType> = {
+  unencrypted: Unencrypted<EncodingType>
+  iv: HexString
+  key: HexString
+  aad?: HexString
+}

packages/sncrypto-common/src/AES-GCM/CryptoAes256GcmInterface.ts

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+import { HexString } from '../Types/HexString'
+import { Aes256GcmEncrypted } from './Aes256GcmEncrypted'
+import { Aes256GcmInput } from './Aes256GcmInput'
+
+export interface CryptoAes256GcmInterface<EncodingType> {
+  /**
+   * Encrypts a string using AES-GCM.
+   * @param input
+   * @returns An object which can be run through aes256GcmDecrypt to retrieve the input text.
+   */
+  aes256GcmEncrypt(input: Aes256GcmInput<EncodingType>): Promise<Aes256GcmEncrypted<EncodingType>>
+
+  /**
+   * Decrypts a string using AES-GCM.
+   * @param encrypted
+   * @param key - encryption key as a hex string
+   * @returns A string encoded with encoding provided in the input
+   */
+  aes256GcmDecrypt(encrypted: Aes256GcmEncrypted<EncodingType>, key: HexString): Promise<string>
+}

packages/sncrypto-common/src/AES-GCM/index.ts

@@ -0,0 +1,3 @@
+export * from './Aes256GcmEncrypted'
+export * from './Aes256GcmInput'
+export * from './CryptoAes256GcmInterface'