AndroidでアプリのSHA1,SHA256を取得するスニペット

GetSignature.kt

@Suppress("DEPRECATION")
@SuppressLint("PackageManagerGetSignatures")
fun getSignature(algorithm: String): String {
    fun byteArrayToReadableString(array: ByteArray, delimiter: String = ":"): String {
        return array.joinToString(delimiter) {
            var str = Integer.toHexString(it.toInt())
            str = (if (str.length == 1) "0$str" else str).replace("ff", "")
            if (str.isEmpty()) str = "FF"
            str.uppercase(Locale.getDefault())
        }
    }

    val signature = packageManager.getPackageInfo(
        packageName,
        PackageManager.GET_SIGNATURES
    ).signatures?.singleOrNull() ?: return "null"

    val md = MessageDigest.getInstance(algorithm)
    md.update(signature.toByteArray())
    return byteArrayToReadableString(md.digest())
}

// 利用例
println("SHA1 ${getSignature("SHA1")}")
println("SHA256 ${getSignature("SHA-256")}")