https://www.proz.com/kudoz/spanish_to_english/law_general/65...

https://www.google.es/search?q="Oblea de seguridad"&rlz=1C1C...

https://assets.publishing.service.gov.uk/government/uploads/...

Discover the advantages and applications of ITW Security Division's Fasprotek™ Passprotek™ Fasver® printed security laminates for passport and ID documents. ITW Security Division is part of ITW Group. We offer Products for ID and Secure Document production, personalization, verification and protection.

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Note added at 1 hr (2018-07-14 16:19:03 GMT)
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Principales cambios en los certificados de nacimiento:

*Es obligatorio el registro de la firma del médico por ante el Registro Civil.
*Se deberán insertar la impresión dígito pulgar derecho de la madre e impresión plantal derecha del recién nacido.
*Se pegará la oblea de seguridad en el libro de partos y en el certificado.
*Las instituciones remitirán los certificados directamente al Registro Civil. No se entregarán a los progenitores.

http://www.noticiasurbanas.com.ar/noticias/el-registro-civil...

I don't think there's an exact translation. In English we talk about stamps and seals that have security features, such as holograms, chips and fibres.

Another solution would be 'embossed security seal'.

U.K. secure passport embeds advanced document security features
Those new security features include:

Using a “continuous sheet of paper” for the laminated personal details page, through to the page that is adjoined to the back cover. “This construction is designed to cause irreparable damage if tampered with, which would be obvious to any person who may need to check the document,” the passport office says.
Embedding into the passport a chip that contains the digital image of the passport holder.
On page three of the passport, a secondary image of the holder of the travel identity document. “When magnified you will see that this image is constructed from the letters and numbers that make up the passport holder’s surname and date of birth,” the passport office says.
That Shakespeare watermark. Not only does the secure passport include the three-dimensional portrait of the playwright and poet, but a “two dimensional watermark of a writer’s scroll, a quill and the corresponding page number.” Additionally, the passport’s personal details page includes a “three-dimensional watermark of the Gipsy Moth IV boat as well as the four floral motifs that represent the U.K—the rose for England, daffodil for Wales, thistle for Scotland, and shamrock for Northern Ireland.” (Gipsy Moth IV is a ketch on which a single British skipper sailed around the world via the route used by old-time clipper ships.)

https://www.secureidnews.com/news-item/new-u-k-secure-passpo...

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Note added at 1 hr (2018-07-14 16:33:23 GMT)
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According to the following reference, the label is stuck onto the certificate, so it might be safer to use 'security label'.

Cuando la documentación ingresa a la DNGU, además de la habitual firma autorizada del Responsable del área de Certificaciones, se coloca una oblea de seguridad, confeccionada en la Casa de la Moneda y provista por el Ministerio de Educación, que también cuenta con un código de barras. Con un lector óptico, se asocian los datos provenientes del código de barras de la etiqueta que pegó en el documento la Universidad, con el código del remito electrónico y el de la oblea que se coloca en la DNGU generando una identidad única para cada graduado y para cada documento certificado. Posteriormente, esta identidad se registrará en un archivo de consulta pública en la página web del Ministerio de Educación.

https://www.ucema.edu.ar/politica-academica/nuevos-diplomas